litmus-rt.git - The LITMUS^RT kernel.

	Commit message (Expand)	Author	Age
*	[PATCH] sysctl: remove insert_at_head from register_sysctl	Eric W. Biederman	2007-02-14
*	[PATCH] sysctl: C99 convert coda ctl_tables and remove binary sysctls	Eric W. Biederman	2007-02-14
*	[PATCH] Mark struct super_operations const	Josef 'Jeff' Sipek	2007-02-12
*	[PATCH] mark struct inode_operations const 1	Arjan van de Ven	2007-02-12
*	[PATCH] seq_file conversion: coda	Alexey Dobriyan	2007-02-11
*	[PATCH] struct path: convert coda	Josef Sipek	2006-12-08
*	[PATCH] slab: remove kmem_cache_t	Christoph Lameter	2006-12-07
*	[PATCH] slab: remove SLAB_KERNEL	Christoph Lameter	2006-12-07
*	[PATCH] r/o bind mount prepwork: inc_nlink() helper	Dave Hansen	2006-10-01
*	[PATCH] r/o bind mounts: unlink: monitor i_nlink	Dave Hansen	2006-10-01
*	[PATCH] inode-diet: Eliminate i_blksize from the inode structure	Theodore Ts'o	2006-09-27
*	[PATCH] Really ignore kmem_cache_destroy return value	Alexey Dobriyan	2006-09-27
*	[PATCH] fs: Removing useless casts	Panagiotis Issaris	2006-09-27
*	[PATCH] Remove incorrect unlock_kernel from allocation failure path in coda_o...	Josh Triplett	2006-07-31
*	Remove obsolete #include <linux/config.h>	Jörn Engel	2006-06-30
*	Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/devfs-2.6	Linus Torvalds	2006-06-29
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\| *	[PATCH] devfs: Remove the devfs_fs_kernel.h file from the tree	Greg Kroah-Hartman	2006-06-26
\| *	[PATCH] devfs: Remove devfs_remove() function from the kernel tree	Greg Kroah-Hartman	2006-06-26
\| *	[PATCH] devfs: Remove devfs_mk_cdev() function from the kernel tree	Greg Kroah-Hartman	2006-06-26
\| *	[PATCH] devfs: Remove devfs_mk_dir() function from the kernel tree	Greg Kroah-Hartman	2006-06-26
* \|	[PATCH] mark address_space_operations const	Christoph Hellwig	2006-06-28
\|/
*	[PATCH] use list_add_tail() instead of list_add()	Akinobu Mita	2006-06-26
*	[PATCH] vfs: add lock owner argument to flush operation	Miklos Szeredi	2006-06-23
*	[PATCH] VFS: Permit filesystem to perform statfs with a known root dentry	David Howells	2006-06-23
*	[PATCH] VFS: Permit filesystem to override root dentry on mount	David Howells	2006-06-23
*	[PATCH] Make most file operations structs in fs/ const	Arjan van de Ven	2006-03-28
*	BUG_ON() Conversion in fs/coda/	Eric Sesterhenn	2006-03-24
*	[PATCH] cpuset memory spread: slab cache filesystems	Paul Jackson	2006-03-24
*	[PATCH] fs/coda/: proper prototypes	Adrian Bunk	2006-03-24
*	[PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem	Jes Sorensen	2006-01-09
*	[PATCH] shrink dentry struct	Eric Dumazet	2006-01-08
*	[PATCH] Driver Core: fix up all callers of class_device_create()	Greg Kroah-Hartman	2005-10-28
*	[PATCH] class: convert the remaining class_simple users in the kernel to usee...	gregkh@suse.de	2005-06-20
*	Linux-2.6.12-rc2v2.6.12-rc2	Linus Torvalds	2005-04-16

/* * SLUB: A slab allocator that limits cache line use instead of queuing * objects in per cpu and per node lists. * * The allocator synchronizes using per slab locks and only * uses a centralized lock to manage a pool of partial slabs. * * (C) 2007 SGI, Christoph Lameter */ #include <linux/mm.h> #include <linux/swap.h> /* struct reclaim_state */ #include <linux/module.h> #include <linux/bit_spinlock.h> #include <linux/interrupt.h> #include <linux/bitops.h> #include <linux/slab.h> #include <linux/proc_fs.h> #include <linux/seq_file.h> #include <linux/kmemcheck.h> #include <linux/cpu.h> #include <linux/cpuset.h> #include <linux/mempolicy.h> #include <linux/ctype.h> #include <linux/debugobjects.h> #include <linux/kallsyms.h> #include <linux/memory.h> #include <linux/math64.h> #include <linux/fault-inject.h> #include <trace/events/kmem.h> /* * Lock order: * 1. slab_lock(page) * 2. slab->list_lock * * The slab_lock protects operations on the object of a particular * slab and its metadata in the page struct. If the slab lock * has been taken then no allocations nor frees can be performed * on the objects in the slab nor can the slab be added or removed * from the partial or full lists since this would mean modifying * the page_struct of the slab. * * The list_lock protects the partial and full list on each node and * the partial slab counter. If taken then no new slabs may be added or * removed from the lists nor make the number of partial slabs be modified. * (Note that the total number of slabs is an atomic value that may be * modified without taking the list lock). * * The list_lock is a centralized lock and thus we avoid taking it as * much as possible. As long as SLUB does not have to handle partial * slabs, operations can continue without any centralized lock. F.e. * allocating a long series of objects that fill up slabs does not require * the list lock. * * The lock order is sometimes inverted when we are trying to get a slab * off a list. We take the list_lock and then look for a page on the list * to use. While we do that objects in the slabs may be freed. We can * only operate on the slab if we have also taken the slab_lock. So we use * a slab_trylock() on the slab. If trylock was successful then no frees * can occur anymore and we can use the slab for allocations etc. If the * slab_trylock() does not succeed then frees are in progress in the slab and * we must stay away from it for a while since we may cause a bouncing * cacheline if we try to acquire the lock. So go onto the next slab. * If all pages are busy then we may allocate a new slab instead of reusing * a partial slab. A new slab has noone operating on it and thus there is * no danger of cacheline contention. * * Interrupts are disabled during allocation and deallocation in order to * make the slab allocator safe to use in the context of an irq. In addition * interrupts are disabled to ensure that the processor does not change * while handling per_cpu slabs, due to kernel preemption. * * SLUB assigns one slab for allocation to each processor. * Allocations only occur from these slabs called cpu slabs. * * Slabs with free elements are kept on a partial list and during regular * operations no list for full slabs is used. If an object in a full slab is * freed then the slab will show up again on the partial lists. * We track full slabs for debugging purposes though because otherwise we * cannot scan all objects. * * Slabs are freed when they become empty. Teardown and setup is * minimal so we rely on the page allocators per cpu caches for * fast frees and allocs. * * Overloading of page flags that are otherwise used for LRU management. * * PageActive The slab is frozen and exempt from list processing. * This means that the slab is dedicated to a purpose * such as satisfying allocations for a specific * processor. Objects may be freed in the slab while * it is frozen but slab_free will then skip the usual * list operations. It is up to the processor holding * the slab to integrate the slab into the slab lists * when the slab is no longer needed. * * One use of this flag is to mark slabs that are * used for allocations. Then such a slab becomes a cpu * slab. The cpu slab may be equipped with an additional * freelist that allows lockless access to * free objects in addition to the regular freelist * that requires the slab lock. * * PageError Slab requires special handling due to debug * options set. This moves slab handling out of * the fast path and disables lockless freelists. */ #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \ SLAB_TRACE | SLAB_DEBUG_FREE) static inline int kmem_cache_debug(struct kmem_cache *s) { #ifdef CONFIG_SLUB_DEBUG return unlikely(s->flags & SLAB_DEBUG_FLAGS); #else return 0; #endif } /* * Issues still to be resolved: * * - Support PAGE_ALLOC_DEBUG. Should be easy to do. * * - Variable sizing of the per node arrays */ /* Enable to test recovery from slab corruption on boot */ #undef SLUB_RESILIENCY_TEST /* * Mininum number of partial slabs. These will be left on the partial * lists even if they are empty. kmem_cache_shrink may reclaim them. */ #define MIN_PARTIAL 5 /* * Maximum number of desirable partial slabs. * The existence of more partial slabs makes kmem_cache_shrink * sort the partial list by the number of objects in the. */ #define MAX_PARTIAL 10 #define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \ SLAB_POISON | SLAB_STORE_USER) /* * Debugging flags that require metadata to be stored in the slab. These get * disabled when slub_debug=O is used and a cache's min order increases with * metadata. */ #define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER) /* * Set of flags that will prevent slab merging */ #define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \ SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \ SLAB_FAILSLAB) #define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \ SLAB_CACHE_DMA | SLAB_NOTRACK) #define OO_SHIFT 16 #define OO_MASK ((1 << OO_SHIFT) - 1) #define MAX_OBJS_PER_PAGE 65535 /* since page.objects is u16 */ /* Internal SLUB flags */ #define __OBJECT_POISON 0x80000000UL /* Poison object */ static int kmem_size = sizeof(struct kmem_cache); #ifdef CONFIG_SMP static struct notifier_block slab_notifier; #endif static enum { DOWN, /* No slab functionality available */ PARTIAL, /* Kmem_cache_node works */ UP, /* Everything works but does not show up in sysfs */ SYSFS /* Sysfs up */ } slab_state = DOWN; /* A list of all slab caches on the system */ static DECLARE_RWSEM(slub_lock); static LIST_HEAD(slab_caches); /* * Tracking user of a slab. */ struct track { unsigned long addr; /* Called from address */ int cpu; /* Was running on cpu */ int pid; /* Pid context */ unsigned long when; /* When did the operation occur */ }; enum track_item { TRACK_ALLOC, TRACK_FREE }; #ifdef CONFIG_SYSFS static int sysfs_slab_add(struct kmem_cache *); static int sysfs_slab_alias(struct kmem_cache *, const char *); static void sysfs_slab_remove(struct kmem_cache *); #else static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; } static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p) { return 0; } static inline void sysfs_slab_remove(struct kmem_cache *s) { kfree(s->name); kfree(s); } #endif static inline void stat(struct kmem_cache *s, enum stat_item si) { #ifdef CONFIG_SLUB_STATS __this_cpu_inc(s->cpu_slab->stat[si]); #endif } /******************************************************************** * Core slab cache functions *******************************************************************/ int slab_is_available(void) { return slab_state >= UP; } static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node) { return s->node[node]; } /* Verify that a pointer has an address that is valid within a slab page */ static inline int check_valid_pointer(struct kmem_cache *s, struct page *page, const void *object) { void *base; if (!object) return 1; base = page_address(page); if (object < base || object >= base + page->objects * s->size || (object - base) % s->size) { return 0; } return 1; } static inline void *get_freepointer(struct kmem_cache *s, void *object) { return *(void **)(object + s->offset); } static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp) { *(void **)(object + s->offset) = fp; } /* Loop over all objects in a slab */ #define for_each_object(__p, __s, __addr, __objects) \ for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\ __p += (__s)->size) /* Scan freelist */ #define for_each_free_object(__p, __s, __free) \ for (__p = (__free); __p; __p = get_freepointer((__s), __p)) /* Determine object index from a given position */ static inline int slab_index(void *p, struct kmem_cache *s, void *addr) { return (p - addr) / s->size; } static inline struct kmem_cache_order_objects oo_make(int order, unsigned long size) { struct kmem_cache_order_objects x = { (order << OO_SHIFT) + (PAGE_SIZE << order) / size }; return x; } static inline int oo_order(struct kmem_cache_order_objects x) { return x.x >> OO_SHIFT; } static inline int oo_objects(struct kmem_cache_order_objects x) { return x.x & OO_MASK; } #ifdef CONFIG_SLUB_DEBUG /* * Debug settings: */ #ifdef CONFIG_SLUB_DEBUG_ON static int slub_debug = DEBUG_DEFAULT_FLAGS; #else static int slub_debug; #endif static char *slub_debug_slabs; static int disable_higher_order_debug; /* * Object debugging */ static void print_section(char *text, u8 *addr, unsigned int length) { int i, offset; int newline = 1; char ascii[17]; ascii[16] = 0; for (i = 0; i < length; i++) { if (newline) { printk(KERN_ERR "%8s 0x%p: ", text, addr + i); newline = 0; } printk(KERN_CONT " %02x", addr[i]); offset = i % 16; ascii[offset] = isgraph(addr[i]) ? addr[i] : '.'; if (offset == 15) { printk(KERN_CONT " %s\n", ascii); newline = 1; } } if (!newline) { i %= 16; while (i < 16) { printk(KERN_CONT " "); ascii[i] = ' '; i++; } printk(KERN_CONT " %s\n", ascii); } } static struct track *get_track(struct kmem_cache *s, void *object, enum track_item alloc) { struct track *p; if (s->offset) p = object + s->offset + sizeof(void *); else p = object + s->inuse; return p + alloc; } static void set_track(struct kmem_cache *s, void *object, enum track_item alloc, unsigned long addr) { struct track *p = get_track(s, object, alloc); if (addr) { p->addr = addr; p->cpu = smp_processor_id(); p->pid = current->pid; p->when = jiffies; } else memset(p, 0, sizeof(struct track)); } static void init_tracking(struct kmem_cache *s, void *object) { if (!(s->flags & SLAB_STORE_USER)) return; set_track(s, object, TRACK_FREE, 0UL); set_track(s, object, TRACK_ALLOC, 0UL); } static void print_track(const char *s, struct track *t) { if (!t->addr) return; printk(KERN_ERR "INFO: %s in %pS age=%lu cpu=%u pid=%d\n", s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid); } static void print_tracking(struct kmem_cache *s, void *object) { if (!(s->flags & SLAB_STORE_USER)) return; print_track("Allocated", get_track(s, object, TRACK_ALLOC)); print_track("Freed", get_track(s, object, TRACK_FREE)); } static void print_page_info(struct page *page) { printk(KERN_ERR "INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n", page, page->objects, page->inuse, page->freelist, page->flags); } static void slab_bug(struct kmem_cache *s, char *fmt, ...) { va_list args; char buf[100]; va_start(args, fmt); vsnprintf(buf, sizeof(buf), fmt, args); va_end(args); printk(KERN_ERR "========================================" "=====================================\n"); printk(KERN_ERR "BUG %s: %s\n", s->name, buf); printk(KERN_ERR "----------------------------------------" "-------------------------------------\n\n"); } static void slab_fix(struct kmem_cache *s, char *fmt, ...) { va_list args; char buf[100]; va_start(args, fmt); vsnprintf(buf, sizeof(buf), fmt, args); va_end(args); printk(KERN_ERR "FIX %s: %s\n", s->name, buf); } static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p) { unsigned int off; /* Offset of last byte */ u8 *addr = page_address(page); print_tracking(s, p); print_page_info(page); printk(KERN_ERR "INFO: Object 0x%p @offset=%tu fp=0x%p\n\n", p, p - addr, get_freepointer(s, p)); if (p > addr + 16) print_section("Bytes b4", p - 16, 16); print_section("Object", p, min_t(unsigned long, s->objsize, PAGE_SIZE)); if (s->flags & SLAB_RED_ZONE) print_section("Redzone", p + s->objsize, s->inuse - s->objsize); if (s->offset) off = s->offset + sizeof(void *); else off = s->inuse; if (s->flags & SLAB_STORE_USER) off += 2 * sizeof(struct track); if (off != s->size) /* Beginning of the filler is the free pointer */ print_section("Padding", p + off, s->size - off); dump_stack(); } static void object_err(struct kmem_cache *s, struct page *page, u8 *object, char *reason) { slab_bug(s, "%s", reason); print_trailer(s, page, object); } static void slab_err(struct kmem_cache *s, struct page *page, char *fmt, ...) { va_list args; char buf[100]; va_start(args, fmt); vsnprintf(buf, sizeof(buf), fmt, args); va_end(args); slab_bug(s, "%s", buf); print_page_info(page); dump_stack(); } static void init_object(struct kmem_cache *s, void *object, u8 val) { u8 *p = object; if (s->flags & __OBJECT_POISON) { memset(p, POISON_FREE, s->objsize - 1); p[s->objsize - 1] = POISON_END; } if (s->flags & SLAB_RED_ZONE) memset(p + s->objsize, val, s->inuse - s->objsize); } static u8 *check_bytes(u8 *start, unsigned int value, unsigned int bytes) { while (bytes) { if (*start != (u8)value) return start; start++; bytes--; } return NULL; } static void restore_bytes(struct kmem_cache *s, char *message, u8 data, void *from, void *to) { slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data); memset(from, data, to - from); } static int check_bytes_and_report(struct kmem_cache *s, struct page *page, u8 *object, char *what, u8 *start, unsigned int value, unsigned int bytes) { u8 *fault; u8 *end; fault = check_bytes(start, value, bytes); if (!fault) return 1; end = start + bytes; while (end > fault && end[-1] == value) end--; slab_bug(s, "%s overwritten", what); printk(KERN_ERR "INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n", fault, end - 1, fault[0], value); print_trailer(s, page, object); restore_bytes(s, what, value, fault, end); return 0; } /* * Object layout: * * object address * Bytes of the object to be managed. * If the freepointer may overlay the object then the free * pointer is the first word of the object. * * Poisoning uses 0x6b (POISON_FREE) and the last byte is * 0xa5 (POISON_END) * * object + s->objsize * Padding to reach word boundary. This is also used for Redzoning. * Padding is extended by another word if Redzoning is enabled and * objsize == inuse. * * We fill with 0xbb (RED_INACTIVE) for inactive objects and with * 0xcc (RED_ACTIVE) for objects in use. * * object + s->inuse * Meta data starts here. * * A. Free pointer (if we cannot overwrite object on free) * B. Tracking data for SLAB_STORE_USER * C. Padding to reach required alignment boundary or at mininum * one word if debugging is on to be able to detect writes * before the word boundary. * * Padding is done using 0x5a (POISON_INUSE) * * object + s->size * Nothing is used beyond s->size. * * If slabcaches are merged then the objsize and inuse boundaries are mostly * ignored. And therefore no slab options that rely on these boundaries * may be used with merged slabcaches. */ static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p) { unsigned long off = s->inuse; /* The end of info */ if (s->offset) /* Freepointer is placed after the object. */ off += sizeof(void *); if (s->flags & SLAB_STORE_USER) /* We also have user information there */ off += 2 * sizeof(struct track); if (s->size == off) return 1; return check_bytes_and_report(s, page, p, "Object padding", p + off, POISON_INUSE, s->size - off); } /* Check the pad bytes at the end of a slab page */ static int slab_pad_check(struct kmem_cache *s, struct page *page) { u8 *start; u8 *fault; u8 *end; int length; int remainder; if (!(s->flags & SLAB_POISON)) return 1; start = page_address(page); length = (PAGE_SIZE << compound_order(page)); end = start + length; remainder = length % s->size; if (!remainder) return 1; fault = check_bytes(end - remainder, POISON_INUSE, remainder); if (!fault) return 1; while (end > fault && end[-1] == POISON_INUSE) end--; slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1); print_section("Padding", end - remainder, remainder); restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end); return 0; } static int check_object(struct kmem_cache *s, struct page *page, void *object, u8 val) { u8 *p = object; u8 *endobject = object + s->objsize; if (s->flags & SLAB_RED_ZONE) { if (!check_bytes_and_report(s, page, object, "Redzone", endobject, val, s->inuse - s->objsize)) return 0; } else { if ((s->flags & SLAB_POISON) && s->objsize < s->inuse) { check_bytes_and_report(s, page, p, "Alignment padding", endobject, POISON_INUSE, s->inuse - s->objsize); } } if (s->flags & SLAB_POISON) { if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) && (!check_bytes_and_report(s, page, p, "Poison", p, POISON_FREE, s->objsize - 1) || !check_bytes_and_report(s, page, p, "Poison", p + s->objsize - 1, POISON_END, 1))) return 0; /* * check_pad_bytes cleans up on its own. */ check_pad_bytes(s, page, p); } if (!s->offset && val == SLUB_RED_ACTIVE) /* * Object and freepointer overlap. Cannot check * freepointer while object is allocated. */ return 1; /* Check free pointer validity */ if (!check_valid_pointer(s, page, get_freepointer(s, p))) { object_err(s, page, p, "Freepointer corrupt"); /* * No choice but to zap it and thus lose the remainder * of the free objects in this slab. May cause * another error because the object count is now wrong. */ set_freepointer(s, p, NULL); return 0; } return 1; } static int check_slab(struct kmem_cache *s, struct page *page) { int maxobj; VM_BUG_ON(!irqs_disabled()); if (!PageSlab(page)) { slab_err(s, page, "Not a valid slab page"); return 0; } maxobj = (PAGE_SIZE << compound_order(page)) / s->size; if (page->objects > maxobj) { slab_err(s, page, "objects %u > max %u", s->name, page->objects, maxobj); return 0; } if (page->inuse > page->objects) { slab_err(s, page, "inuse %u > max %u", s->name, page->inuse, page->objects); return 0; } /* Slab_pad_check fixes things up after itself */ slab_pad_check(s, page); return 1; } /* * Determine if a certain object on a page is on the freelist. Must hold the * slab lock to guarantee that the chains are in a consistent state. */ static int on_freelist(struct kmem_cache *s, struct page *page, void *search) { int nr = 0; void *fp = page->freelist; void *object = NULL; unsigned long max_objects; while (fp && nr <= page->objects) { if (fp == search) return 1; if (!check_valid_pointer(s, page, fp)) { if (object) { object_err(s, page, object, "Freechain corrupt"); set_freepointer(s, object, NULL); break; } else { slab_err(s, page, "Freepointer corrupt"); page->freelist = NULL; page->inuse = page->objects; slab_fix(s, "Freelist cleared"); return 0; } break; } object = fp; fp = get_freepointer(s, object); nr++; } max_objects = (PAGE_SIZE << compound_order(page)) / s->size; if (max_objects > MAX_OBJS_PER_PAGE) max_objects = MAX_OBJS_PER_PAGE; if (page->objects != max_objects) { slab_err(s, page, "Wrong number of objects. Found %d but " "should be %d", page->objects, max_objects); page->objects = max_objects; slab_fix(s, "Number of objects adjusted."); } if (page->inuse != page->objects - nr) { slab_err(s, page, "Wrong object count. Counter is %d but " "counted were %d", page->inuse, page->objects - nr); page->inuse = page->objects - nr; slab_fix(s, "Object count adjusted."); } return search == NULL; } static void trace(struct kmem_cache *s, struct page *page, void *object, int alloc) { if (s->flags & SLAB_TRACE) { printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n", s->name, alloc ? "alloc" : "free", object, page->inuse, page->freelist); if (!alloc) print_section("Object", (void *)object, s->objsize); dump_stack(); } } /* * Hooks for other subsystems that check memory allocations. In a typical * production configuration these hooks all should produce no code at all. */ static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags) { flags &= gfp_allowed_mask; lockdep_trace_alloc(flags); might_sleep_if(flags & __GFP_WAIT); return should_failslab(s->objsize, flags, s->flags); } static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, void *object) { flags &= gfp_allowed_mask; kmemcheck_slab_alloc(s, flags, object, s->objsize); kmemleak_alloc_recursive(object, s->objsize, 1, s->flags, flags); } static inline void slab_free_hook(struct kmem_cache *s, void *x) { kmemleak_free_recursive(x, s->flags); } static inline void slab_free_hook_irq(struct kmem_cache *s, void *object) { kmemcheck_slab_free(s, object, s->objsize); debug_check_no_locks_freed(object, s->objsize); if (!(s->flags & SLAB_DEBUG_OBJECTS)) debug_check_no_obj_freed(object, s->objsize); } /* * Tracking of fully allocated slabs for debugging purposes. */ static void add_full(struct kmem_cache_node *n, struct page *page) { spin_lock(&n->list_lock); list_add(&page->lru, &n->full); spin_unlock(&n->list_lock); } static void remove_full(struct kmem_cache *s, struct page *page) { struct kmem_cache_node *n; if (!(s->flags & SLAB_STORE_USER)) return; n = get_node(s, page_to_nid(page)); spin_lock(&n->list_lock); list_del(&page->lru); spin_unlock(&n->list_lock); } /* Tracking of the number of slabs for debugging purposes */ static inline unsigned long slabs_node(struct kmem_cache *s, int node) { struct kmem_cache_node *n = get_node(s, node); return atomic_long_read(&n->nr_slabs); } static inline unsigned long node_nr_slabs(struct kmem_cache_node *n) { return atomic_long_read(&n->nr_slabs); } static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects) { struct kmem_cache_node *n = get_node(s, node); /* * May be called early in order to allocate a slab for the * kmem_cache_node structure. Solve the chicken-egg * dilemma by deferring the increment of the count during * bootstrap (see early_kmem_cache_node_alloc). */ if (n) { atomic_long_inc(&n->nr_slabs); atomic_long_add(objects, &n->total_objects); } } static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects) { struct kmem_cache_node *n = get_node(s, node); atomic_long_dec(&n->nr_slabs); atomic_long_sub(objects, &n->total_objects); } /* Object debug checks for alloc/free paths */ static void setup_object_debug(struct kmem_cache *s, struct page *page, void *object) { if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON))) return; init_object(s, object, SLUB_RED_INACTIVE); init_tracking(s, object); } static noinline int alloc_debug_processing(struct kmem_cache *s, struct page *page, void *object, unsigned long addr) { if (!check_slab(s, page)) goto bad; if (!on_freelist(s, page, object)) { object_err(s, page, object, "Object already allocated"); goto bad; } if (!check_valid_pointer(s, page, object)) { object_err(s, page, object, "Freelist Pointer check fails"); goto bad; } if (!check_object(s, page, object, SLUB_RED_INACTIVE)) goto bad; /* Success perform special debug activities for allocs */ if (s->flags & SLAB_STORE_USER) set_track(s, object, TRACK_ALLOC, addr); trace(s, page, object, 1); init_object(s, object, SLUB_RED_ACTIVE); return 1; bad: if (PageSlab(page)) { /* * If this is a slab page then lets do the best we can * to avoid issues in the future. Marking all objects * as used avoids touching the remaining objects. */ slab_fix(s, "Marking all objects used"); page->inuse = page->objects; page->freelist = NULL; } return 0; } static noinline int free_debug_processing(struct kmem_cache *s, struct page *page, void *object, unsigned long addr) { if (!check_slab(s, page)) goto fail; if (!check_valid_pointer(s, page, object)) { slab_err(s, page, "Invalid object pointer 0x%p", object); goto fail; } if (on_freelist(s, page, object)) { object_err(s, page, object, "Object already free"); goto fail; } if (!check_object(s, page, object, SLUB_RED_ACTIVE)) return 0; if (unlikely(s != page->slab)) { if (!PageSlab(page)) { slab_err(s, page, "Attempt to free object(0x%p) " "outside of slab", object); } else if (!page->slab) { printk(KERN_ERR "SLUB <none>: no slab for object 0x%p.\n", object); dump_stack(); } else object_err(s, page, object, "page slab pointer corrupt."); goto fail; } /* Special debug activities for freeing objects */ if (!PageSlubFrozen(page) && !page->freelist) remove_full(s, page); if (s->flags & SLAB_STORE_USER) set_track(s, object, TRACK_FREE, addr); trace(s, page, object, 0); init_object(s, object, SLUB_RED_INACTIVE); return 1; fail: slab_fix(s, "Object at 0x%p not freed", object); return 0; } static int __init setup_slub_debug(char *str) { slub_debug = DEBUG_DEFAULT_FLAGS; if (*str++ != '=' || !*str) /* * No options specified. Switch on full debugging. */ goto out; if (*str == ',') /* * No options but restriction on slabs. This means full * debugging for slabs matching a pattern. */ goto check_slabs; if (tolower(*str) == 'o') { /* * Avoid enabling debugging on caches if its minimum order * would increase as a result. */ disable_higher_order_debug = 1; goto out; } slub_debug = 0; if (*str == '-') /* * Switch off all debugging measures. */ goto out; /* * Determine which debug features should be switched on */ for (; *str && *str != ','; str++) { switch (tolower(*str)) { case 'f': slub_debug |= SLAB_DEBUG_FREE; break; case 'z': slub_debug |= SLAB_RED_ZONE; break; case 'p': slub_debug |= SLAB_POISON; break; case 'u': slub_debug |= SLAB_STORE_USER; break; case 't': slub_debug |= SLAB_TRACE; break; case 'a': slub_debug |= SLAB_FAILSLAB; break; default: printk(KERN_ERR "slub_debug option '%c' " "unknown. skipped\n", *str); } } check_slabs: if (*str == ',') slub_debug_slabs = str + 1; out: return 1; } __setup("slub_debug", setup_slub_debug); static unsigned long kmem_cache_flags(unsigned long objsize, unsigned long flags, const char *name, void (*ctor)(void *)) { /* * Enable debugging if selected on the kernel commandline. */ if (slub_debug && (!slub_debug_slabs || !strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs)))) flags |= slub_debug; return flags; } #else static inline void setup_object_debug(struct kmem_cache *s, struct page *page, void *object) {} static inline int alloc_debug_processing(struct kmem_cache *s, struct page *page, void *object, unsigned long addr) { return 0; } static inline int free_debug_processing(struct kmem_cache *s, struct page *page, void *object, unsigned long addr) { return 0; } static inline int slab_pad_check(struct kmem_cache *s, struct page *page) { return 1; } static inline int check_object(struct kmem_cache *s, struct page *page, void *object, u8 val) { return 1; } static inline void add_full(struct kmem_cache_node *n, struct page *page) {} static inline unsigned long kmem_cache_flags(unsigned long objsize, unsigned long flags, const char *name, void (*ctor)(void *)) { return flags; } #define slub_debug 0 #define disable_higher_order_debug 0 static inline unsigned long slabs_node(struct kmem_cache *s, int node) { return 0; } static inline unsigned long node_nr_slabs(struct kmem_cache_node *n) { return 0; } static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects) {} static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects) {} static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags) { return 0; } static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, void *object) {} static inline void slab_free_hook(struct kmem_cache *s, void *x) {} static inline void slab_free_hook_irq(struct kmem_cache *s, void *object) {} #endif /* CONFIG_SLUB_DEBUG */ /* * Slab allocation and freeing */ static inline struct page *alloc_slab_page(gfp_t flags, int node, struct kmem_cache_order_objects oo) { int order = oo_order(oo); flags |= __GFP_NOTRACK; if (node == NUMA_NO_NODE) return alloc_pages(flags, order); else return alloc_pages_exact_node(node, flags, order); } static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) { struct page *page; struct kmem_cache_order_objects oo = s->oo; gfp_t alloc_gfp; flags |= s->allocflags; /* * Let the initial higher-order allocation fail under memory pressure * so we fall-back to the minimum order allocation. */ alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL; page = alloc_slab_page(alloc_gfp, node, oo); if (unlikely(!page)) { oo = s->min; /* * Allocation may have failed due to fragmentation. * Try a lower order alloc if possible */ page = alloc_slab_page(flags, node, oo); if (!page) return NULL; stat(s, ORDER_FALLBACK); } if (kmemcheck_enabled && !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) { int pages = 1 << oo_order(oo); kmemcheck_alloc_shadow(page, oo_order(oo), flags, node); /* * Objects from caches that have a constructor don't get * cleared when they're allocated, so we need to do it here. */ if (s->ctor) kmemcheck_mark_uninitialized_pages(page, pages); else kmemcheck_mark_unallocated_pages(page, pages); } page->objects = oo_objects(oo); mod_zone_page_state(page_zone(page), (s->flags & SLAB_RECLAIM_ACCOUNT) ? NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE, 1 << oo_order(oo)); return page; } static void setup_object(struct kmem_cache *s, struct page *page, void *object) { setup_object_debug(s, page, object); if (unlikely(s->ctor)) s->ctor(object); } static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node) { struct page *page; void *start; void *last; void *p; BUG_ON(flags & GFP_SLAB_BUG_MASK); page = allocate_slab(s, flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node); if (!page) goto out; inc_slabs_node(s, page_to_nid(page), page->objects); page->slab = s; page->flags |= 1 << PG_slab; start = page_address(page); if (unlikely(s->flags & SLAB_POISON)) memset(start, POISON_INUSE, PAGE_SIZE << compound_order(page)); last = start; for_each_object(p, s, start, page->objects) { setup_object(s, page, last); set_freepointer(s, last, p); last = p; } setup_object(s, page, last); set_freepointer(s, last, NULL); page->freelist = start; page->inuse = 0; out: return page; } static void __free_slab(struct kmem_cache *s, struct page *page) { int order = compound_order(page); int pages = 1 << order; if (kmem_cache_debug(s)) { void *p; slab_pad_check(s, page); for_each_object(p, s, page_address(page), page->objects) check_object(s, page, p, SLUB_RED_INACTIVE); } kmemcheck_free_shadow(page, compound_order(page)); mod_zone_page_state(page_zone(page), (s->flags & SLAB_RECLAIM_ACCOUNT) ? NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE, -pages); __ClearPageSlab(page); reset_page_mapcount(page); if (current->reclaim_state) current->reclaim_state->reclaimed_slab += pages; __free_pages(page, order); } static void rcu_free_slab(struct rcu_head *h) { struct page *page; page = container_of((struct list_head *)h, struct page, lru); __free_slab(page->slab, page); } static void free_slab(struct kmem_cache *s, struct page *page) { if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) { /* * RCU free overloads the RCU head over the LRU */ struct rcu_head *head = (void *)&page->lru; call_rcu(head, rcu_free_slab); } else __free_slab(s, page); } static void discard_slab(struct kmem_cache *s, struct page *page) { dec_slabs_node(s, page_to_nid(page), page->objects); free_slab(s, page); } /* * Per slab locking using the pagelock */ static __always_inline void slab_lock(struct page *page) { bit_spin_lock(PG_locked, &page->flags); } static __always_inline void slab_unlock(struct page *page) { __bit_spin_unlock(PG_locked, &page->flags); } static __always_inline int slab_trylock(struct page *page) { int rc = 1; rc = bit_spin_trylock(PG_locked, &page->flags); return rc; } /* * Management of partially allocated slabs */ static void add_partial(struct kmem_cache_node *n, struct page *page, int tail) { spin_lock(&n->list_lock); n->nr_partial++; if (tail) list_add_tail(&page->lru, &n->partial); else list_add(&page->lru, &n->partial); spin_unlock(&n->list_lock); } static inline void __remove_partial(struct kmem_cache_node *n, struct page *page) { list_del(&page->lru); n->nr_partial--; } static void remove_partial(struct kmem_cache *s, struct page *page) { struct kmem_cache_node *n = get_node(s, page_to_nid(page)); spin_lock(&n->list_lock); __remove_partial(n, page); spin_unlock(&n->list_lock); } /* * Lock slab and remove from the partial list. * * Must hold list_lock. */ static inline int lock_and_freeze_slab(struct kmem_cache_node *n, struct page *page) { if (slab_trylock(page)) { __remove_partial(n, page); __SetPageSlubFrozen(page); return 1; } return 0; } /* * Try to allocate a partial slab from a specific node. */ static struct page *get_partial_node(struct kmem_cache_node *n) { struct page *page; /* * Racy check. If we mistakenly see no partial slabs then we * just allocate an empty slab. If we mistakenly try to get a * partial slab and there is none available then get_partials() * will return NULL. */ if (!n || !n->nr_partial) return NULL; spin_lock(&n->list_lock); list_for_each_entry(page, &n->partial, lru) if (lock_and_freeze_slab(n, page)) goto out; page = NULL; out: spin_unlock(&n->list_lock); return page; } /* * Get a page from somewhere. Search in increasing NUMA distances. */ static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags) { #ifdef CONFIG_NUMA struct zonelist *zonelist; struct zoneref *z; struct zone *zone; enum zone_type high_zoneidx = gfp_zone(flags); struct page *page; /* * The defrag ratio allows a configuration of the tradeoffs between * inter node defragmentation and node local allocations. A lower * defrag_ratio increases the tendency to do local allocations * instead of attempting to obtain partial slabs from other nodes. * * If the defrag_ratio is set to 0 then kmalloc() always * returns node local objects. If the ratio is higher then kmalloc() * may return off node objects because partial slabs are obtained * from other nodes and filled up. * * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes * defrag_ratio = 1000) then every (well almost) allocation will * first attempt to defrag slab caches on other nodes. This means * scanning over all nodes to look for partial slabs which may be * expensive if we do it every time we are trying to find a slab * with available objects. */ if (!s->remote_node_defrag_ratio || get_cycles() % 1024 > s->remote_node_defrag_ratio) return NULL; get_mems_allowed(); zonelist = node_zonelist(slab_node(current->mempolicy), flags); for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) { struct kmem_cache_node *n; n = get_node(s, zone_to_nid(zone)); if (n && cpuset_zone_allowed_hardwall(zone, flags) && n->nr_partial > s->min_partial) { page = get_partial_node(n); if (page) { put_mems_allowed(); return page; } } } put_mems_allowed(); #endif return NULL; } /* * Get a partial page, lock it and return it. */ static struct page *get_partial(struct kmem_cache *s, gfp_t flags, int node) { struct page *page; int searchnode = (node == NUMA_NO_NODE) ? numa_node_id() : node; page = get_partial_node(get_node(s, searchnode)); if (page || node != -1) return page; return get_any_partial(s, flags); } /* * Move a page back to the lists. * * Must be called with the slab lock held. * * On exit the slab lock will have been dropped. */ static void unfreeze_slab(struct kmem_cache *s, struct page *page, int tail) __releases(bitlock) { struct kmem_cache_node *n = get_node(s, page_to_nid(page)); __ClearPageSlubFrozen(page); if (page->inuse) { if (page->freelist) { add_partial(n, page, tail); stat(s, tail ? DEACTIVATE_TO_TAIL : DEACTIVATE_TO_HEAD); } else { stat(s, DEACTIVATE_FULL); if (kmem_cache_debug(s) && (s->flags & SLAB_STORE_USER)) add_full(n, page); } slab_unlock(page); } else { stat(s, DEACTIVATE_EMPTY); if (n->nr_partial < s->min_partial) { /* * Adding an empty slab to the partial slabs in order * to avoid page allocator overhead. This slab needs * to come after the other slabs with objects in * so that the others get filled first. That way the * size of the partial list stays small. * * kmem_cache_shrink can reclaim any empty slabs from * the partial list. */ add_partial(n, page, 1); slab_unlock(page); } else { slab_unlock(page); stat(s, FREE_SLAB); discard_slab(s, page); } } } /* * Remove the cpu slab */ static void deactivate_slab(struct kmem_cache *s, struct kmem_cache_cpu *c) __releases(bitlock) { struct page *page = c->page; int tail = 1; if (page->freelist) stat(s, DEACTIVATE_REMOTE_FREES); /* * Merge cpu freelist into slab freelist. Typically we get here * because both freelists are empty. So this is unlikely * to occur. */ while (unlikely(c->freelist)) { void **object; tail = 0; /* Hot objects. Put the slab first */ /* Retrieve object from cpu_freelist */ object = c->freelist; c->freelist = get_freepointer(s, c->freelist); /* And put onto the regular freelist */ set_freepointer(s, object, page->freelist); page->freelist = object; page->inuse--; } c->page = NULL; unfreeze_slab(s, page, tail); } static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c) { stat(s, CPUSLAB_FLUSH); slab_lock(c->page); deactivate_slab(s, c); } /* * Flush cpu slab. * * Called from IPI handler with interrupts disabled. */ static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu) { struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu); if (likely(c && c->page)) flush_slab(s, c); } static void flush_cpu_slab(void *d) { struct kmem_cache *s = d; __flush_cpu_slab(s, smp_processor_id()); } static void flush_all(struct kmem_cache *s) { on_each_cpu(flush_cpu_slab, s, 1); } /* * Check if the objects in a per cpu structure fit numa * locality expectations. */ static inline int node_match(struct kmem_cache_cpu *c, int node) { #ifdef CONFIG_NUMA if (node != NUMA_NO_NODE && c->node != node) return 0; #endif return 1; } static int count_free(struct page *page) { return page->objects - page->inuse; } static unsigned long count_partial(struct kmem_cache_node *n, int (*get_count)(struct page *)) { unsigned long flags; unsigned long x = 0; struct page *page; spin_lock_irqsave(&n->list_lock, flags); list_for_each_entry(page, &n->partial, lru) x += get_count(page); spin_unlock_irqrestore(&n->list_lock, flags); return x; } static inline unsigned long node_nr_objs(struct kmem_cache_node *n) { #ifdef CONFIG_SLUB_DEBUG return atomic_long_read(&n->total_objects); #else return 0; #endif } static noinline void slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid) { int node; printk(KERN_WARNING "SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n", nid, gfpflags); printk(KERN_WARNING " cache: %s, object size: %d, buffer size: %d, " "default order: %d, min order: %d\n", s->name, s->objsize, s->size, oo_order(s->oo), oo_order(s->min)); if (oo_order(s->min) > get_order(s->objsize)) printk(KERN_WARNING " %s debugging increased min order, use " "slub_debug=O to disable.\n", s->name); for_each_online_node(node) { struct kmem_cache_node *n = get_node(s, node); unsigned long nr_slabs; unsigned long nr_objs; unsigned long nr_free; if (!n) continue; nr_free = count_partial(n, count_free); nr_slabs = node_nr_slabs(n); nr_objs = node_nr_objs(n); printk(KERN_WARNING " node %d: slabs: %ld, objs: %ld, free: %ld\n", node, nr_slabs, nr_objs, nr_free); } } /* * Slow path. The lockless freelist is empty or we need to perform * debugging duties. * * Interrupts are disabled. * * Processing is still very fast if new objects have been freed to the * regular freelist. In that case we simply take over the regular freelist * as the lockless freelist and zap the regular freelist. * * If that is not working then we fall back to the partial lists. We take the * first element of the freelist as the object to allocate now and move the * rest of the freelist to the lockless freelist. * * And if we were unable to get a new slab from the partial slab lists then * we need to allocate a new slab. This is the slowest path since it involves * a call to the page allocator and the setup of a new slab. */ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, unsigned long addr, struct kmem_cache_cpu *c) { void **object; struct page *new; /* We handle __GFP_ZERO in the caller */ gfpflags &= ~__GFP_ZERO; if (!c->page) goto new_slab; slab_lock(c->page); if (unlikely(!node_match(c, node))) goto another_slab; stat(s, ALLOC_REFILL); load_freelist: object = c->page->freelist; if (unlikely(!object)) goto another_slab; if (kmem_cache_debug(s)) goto debug; c->freelist = get_freepointer(s, object); c->page->inuse = c->page->objects; c->page->freelist = NULL; c->node = page_to_nid(c->page); unlock_out: slab_unlock(c->page); stat(s, ALLOC_SLOWPATH); return object; another_slab: deactivate_slab(s, c); new_slab: new = get_partial(s, gfpflags, node); if (new) { c->page = new; stat(s, ALLOC_FROM_PARTIAL); goto load_freelist; } gfpflags &= gfp_allowed_mask; if (gfpflags & __GFP_WAIT) local_irq_enable(); new = new_slab(s, gfpflags, node); if (gfpflags & __GFP_WAIT) local_irq_disable(); if (new) { c = __this_cpu_ptr(s->cpu_slab); stat(s, ALLOC_SLAB); if (c->page) flush_slab(s, c); slab_lock(new); __SetPageSlubFrozen(new); c->page = new; goto load_freelist; } if (!(gfpflags & __GFP_NOWARN) && printk_ratelimit()) slab_out_of_memory(s, gfpflags, node); return NULL; debug: if (!alloc_debug_processing(s, c->page, object, addr)) goto another_slab; c->page->inuse++; c->page->freelist = get_freepointer(s, object); c->node = NUMA_NO_NODE; goto unlock_out; } /* * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc) * have the fastpath folded into their functions. So no function call * overhead for requests that can be satisfied on the fastpath. * * The fastpath works by first checking if the lockless freelist can be used. * If not then __slab_alloc is called for slow processing. * * Otherwise we can simply pick the next object from the lockless free list. */ static __always_inline void *slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, unsigned long addr) { void **object; struct kmem_cache_cpu *c; unsigned long flags; if (slab_pre_alloc_hook(s, gfpflags)) return NULL; local_irq_save(flags); c = __this_cpu_ptr(s->cpu_slab); object = c->freelist; if (unlikely(!object || !node_match(c, node))) object = __slab_alloc(s, gfpflags, node, addr, c); else { c->freelist = get_freepointer(s, object); stat(s, ALLOC_FASTPATH); } local_irq_restore(flags); if (unlikely(gfpflags & __GFP_ZERO) && object) memset(object, 0, s->objsize); slab_post_alloc_hook(s, gfpflags, object); return object; } void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags) { void *ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, _RET_IP_); trace_kmem_cache_alloc(_RET_IP_, ret, s->objsize, s->size, gfpflags); return ret; } EXPORT_SYMBOL(kmem_cache_alloc); #ifdef CONFIG_TRACING void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size) { void *ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, _RET_IP_); trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags); return ret; } EXPORT_SYMBOL(kmem_cache_alloc_trace); void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order) { void *ret = kmalloc_order(size, flags, order); trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags); return ret; } EXPORT_SYMBOL(kmalloc_order_trace); #endif #ifdef CONFIG_NUMA void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node) { void *ret = slab_alloc(s, gfpflags, node, _RET_IP_); trace_kmem_cache_alloc_node(_RET_IP_, ret, s->objsize, s->size, gfpflags, node); return ret; } EXPORT_SYMBOL(kmem_cache_alloc_node); #ifdef CONFIG_TRACING void *kmem_cache_alloc_node_trace(struct kmem_cache *s, gfp_t gfpflags, int node, size_t size) { void *ret = slab_alloc(s, gfpflags, node, _RET_IP_); trace_kmalloc_node(_RET_IP_, ret, size, s->size, gfpflags, node); return ret; } EXPORT_SYMBOL(kmem_cache_alloc_node_trace); #endif #endif /* * Slow patch handling. This may still be called frequently since objects * have a longer lifetime than the cpu slabs in most processing loads. * * So we still attempt to reduce cache line usage. Just take the slab * lock and free the item. If there is no additional partial page * handling required then we can return immediately. */ static void __slab_free(struct kmem_cache *s, struct page *page, void *x, unsigned long addr) { void *prior; void **object = (void *)x; stat(s, FREE_SLOWPATH); slab_lock(page); if (kmem_cache_debug(s)) goto debug; checks_ok: prior = page->freelist; set_freepointer(s, object, prior); page->freelist = object; page->inuse--; if (unlikely(PageSlubFrozen(page))) { stat(s, FREE_FROZEN); goto out_unlock; } if (unlikely(!page->inuse)) goto slab_empty; /* * Objects left in the slab. If it was not on the partial list before * then add it. */ if (unlikely(!prior)) { add_partial(get_node(s, page_to_nid(page)), page, 1); stat(s, FREE_ADD_PARTIAL); } out_unlock: slab_unlock(page); return; slab_empty: if (prior) { /* * Slab still on the partial list. */ remove_partial(s, page); stat(s, FREE_REMOVE_PARTIAL); } slab_unlock(page); stat(s, FREE_SLAB); discard_slab(s, page); return; debug: if (!free_debug_processing(s, page, x, addr)) goto out_unlock; goto checks_ok; } /* * Fastpath with forced inlining to produce a kfree and kmem_cache_free that * can perform fastpath freeing without additional function calls. * * The fastpath is only possible if we are freeing to the current cpu slab * of this processor. This typically the case if we have just allocated * the item before. * * If fastpath is not possible then fall back to __slab_free where we deal * with all sorts of special processing. */ static __always_inline void slab_free(struct kmem_cache *s, struct page *page, void *x, unsigned long addr) { void **object = (void *)x; struct kmem_cache_cpu *c; unsigned long flags; slab_free_hook(s, x); local_irq_save(flags); c = __this_cpu_ptr(s->cpu_slab); slab_free_hook_irq(s, x); if (likely(page == c->page && c->node != NUMA_NO_NODE)) { set_freepointer(s, object, c->freelist); c->freelist = object; stat(s, FREE_FASTPATH); } else __slab_free(s, page, x, addr); local_irq_restore(flags); } void kmem_cache_free(struct kmem_cache *s, void *x) { struct page *page; page = virt_to_head_page(x); slab_free(s, page, x, _RET_IP_); trace_kmem_cache_free(_RET_IP_, x); } EXPORT_SYMBOL(kmem_cache_free); /* Figure out on which slab page the object resides */ static struct page *get_object_page(const void *x) { struct page *page = virt_to_head_page(x); if (!PageSlab(page)) return NULL; return page; } /* * Object placement in a slab is made very easy because we always start at * offset 0. If we tune the size of the object to the alignment then we can * get the required alignment by putting one properly sized object after * another. * * Notice that the allocation order determines the sizes of the per cpu * caches. Each processor has always one slab available for allocations. * Increasing the allocation order reduces the number of times that slabs * must be moved on and off the partial lists and is therefore a factor in * locking overhead. */ /* * Mininum / Maximum order of slab pages. This influences locking overhead * and slab fragmentation. A higher order reduces the number of partial slabs * and increases the number of allocations possible without having to * take the list_lock. */ static int slub_min_order; static int slub_max_order = PAGE_ALLOC_COSTLY_ORDER; static int slub_min_objects; /* * Merge control. If this is set then no merging of slab caches will occur. * (Could be removed. This was introduced to pacify the merge skeptics.) */ static int slub_nomerge; /* * Calculate the order of allocation given an slab object size. * * The order of allocation has significant impact on performance and other * system components. Generally order 0 allocations should be preferred since * order 0 does not cause fragmentation in the page allocator. Larger objects * be problematic to put into order 0 slabs because there may be too much * unused space left. We go to a higher order if more than 1/16th of the slab * would be wasted. * * In order to reach satisfactory performance we must ensure that a minimum * number of objects is in one slab. Otherwise we may generate too much * activity on the partial lists which requires taking the list_lock. This is * less a concern for large slabs though which are rarely used. * * slub_max_order specifies the order where we begin to stop considering the * number of objects in a slab as critical. If we reach slub_max_order then * we try to keep the page order as low as possible. So we accept more waste * of space in favor of a small page order. * * Higher order allocations also allow the placement of more objects in a * slab and thereby reduce object handling overhead. If the user has * requested a higher mininum order then we start with that one instead of * the smallest order which will fit the object. */ static inline int slab_order(int size, int min_objects, int max_order, int fract_leftover) { int order; int rem; int min_order = slub_min_order; if ((PAGE_SIZE << min_order) / size > MAX_OBJS_PER_PAGE) return get_order(size * MAX_OBJS_PER_PAGE) - 1; for (order = max(min_order, fls(min_objects * size - 1) - PAGE_SHIFT); order <= max_order; order++) { unsigned long slab_size = PAGE_SIZE << order; if (slab_size < min_objects * size) continue; rem = slab_size % size; if (rem <= slab_size / fract_leftover) break; } return order; } static inline int calculate_order(int size) { int order; int min_objects; int fraction; int max_objects; /* * Attempt to find best configuration for a slab. This * works by first attempting to generate a layout with * the best configuration and backing off gradually. * * First we reduce the acceptable waste in a slab. Then * we reduce the minimum objects required in a slab. */ min_objects = slub_min_objects; if (!min_objects) min_objects = 4 * (fls(nr_cpu_ids) + 1); max_objects = (PAGE_SIZE << slub_max_order)/size; min_objects = min(min_objects, max_objects); while (min_objects > 1) { fraction = 16; while (fraction >= 4) { order = slab_order(size, min_objects, slub_max_order, fraction); if (order <= slub_max_order) return order; fraction /= 2; } min_objects--; } /* * We were unable to place multiple objects in a slab. Now * lets see if we can place a single object there. */ order = slab_order(size, 1, slub_max_order, 1); if (order <= slub_max_order) return order; /* * Doh this slab cannot be placed using slub_max_order. */ order = slab_order(size, 1, MAX_ORDER, 1); if (order < MAX_ORDER) return order; return -ENOSYS; } /* * Figure out what the alignment of the objects will be. */ static unsigned long calculate_alignment(unsigned long flags, unsigned long align, unsigned long size) { /* * If the user wants hardware cache aligned objects then follow that * suggestion if the object is sufficiently large. * * The hardware cache alignment cannot override the specified * alignment though. If that is greater then use it. */ if (flags & SLAB_HWCACHE_ALIGN) { unsigned long ralign = cache_line_size(); while (size <= ralign / 2) ralign /= 2; align = max(align, ralign); } if (align < ARCH_SLAB_MINALIGN) align = ARCH_SLAB_MINALIGN; return ALIGN(align, sizeof(void *)); } static void init_kmem_cache_node(struct kmem_cache_node *n, struct kmem_cache *s) { n->nr_partial = 0; spin_lock_init(&n->list_lock); INIT_LIST_HEAD(&n->partial); #ifdef CONFIG_SLUB_DEBUG atomic_long_set(&n->nr_slabs, 0); atomic_long_set(&n->total_objects, 0); INIT_LIST_HEAD(&n->full); #endif } static inline int alloc_kmem_cache_cpus(struct kmem_cache *s) { BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE < SLUB_PAGE_SHIFT * sizeof(struct kmem_cache_cpu)); s->cpu_slab = alloc_percpu(struct kmem_cache_cpu); return s->cpu_slab != NULL; } static struct kmem_cache *kmem_cache_node; /* * No kmalloc_node yet so do it by hand. We know that this is the first * slab on the node for this slabcache. There are no concurrent accesses * possible. * * Note that this function only works on the kmalloc_node_cache * when allocating for the kmalloc_node_cache. This is used for bootstrapping * memory on a fresh node that has no slab structures yet. */ static void early_kmem_cache_node_alloc(int node) { struct page *page; struct kmem_cache_node *n; unsigned long flags; BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node)); page = new_slab(kmem_cache_node, GFP_NOWAIT, node); BUG_ON(!page); if (page_to_nid(page) != node) { printk(KERN_ERR "SLUB: Unable to allocate memory from " "node %d\n", node); printk(KERN_ERR "SLUB: Allocating a useless per node structure " "in order to be able to continue\n"); } n = page->freelist; BUG_ON(!n); page->freelist = get_freepointer(kmem_cache_node, n); page->inuse++; kmem_cache_node->node[node] = n; #ifdef CONFIG_SLUB_DEBUG init_object(kmem_cache_node, n, SLUB_RED_ACTIVE); init_tracking(kmem_cache_node, n); #endif init_kmem_cache_node(n, kmem_cache_node); inc_slabs_node(kmem_cache_node, node, page->objects); /* * lockdep requires consistent irq usage for each lock * so even though there cannot be a race this early in * the boot sequence, we still disable irqs. */ local_irq_save(flags); add_partial(n, page, 0); local_irq_restore(flags); } static void free_kmem_cache_nodes(struct kmem_cache *s) { int node; for_each_node_state(node, N_NORMAL_MEMORY) { struct kmem_cache_node *n = s->node[node]; if (n) kmem_cache_free(kmem_cache_node, n); s->node[node] = NULL; } } static int init_kmem_cache_nodes(struct kmem_cache *s) { int node; for_each_node_state(node, N_NORMAL_MEMORY) { struct kmem_cache_node *n; if (slab_state == DOWN) { early_kmem_cache_node_alloc(node); continue; } n = kmem_cache_alloc_node(kmem_cache_node, GFP_KERNEL, node); if (!n) { free_kmem_cache_nodes(s); return 0; } s->node[node] = n; init_kmem_cache_node(n, s); } return 1; } static void set_min_partial(struct kmem_cache *s, unsigned long min) { if (min < MIN_PARTIAL) min = MIN_PARTIAL; else if (min > MAX_PARTIAL) min = MAX_PARTIAL; s->min_partial = min; } /* * calculate_sizes() determines the order and the distribution of data within * a slab object. */ static int calculate_sizes(struct kmem_cache *s, int forced_order) { unsigned long flags = s->flags; unsigned long size = s->objsize; unsigned long align = s->align; int order; /* * Round up object size to the next word boundary. We can only * place the free pointer at word boundaries and this determines * the possible location of the free pointer. */ size = ALIGN(size, sizeof(void *)); #ifdef CONFIG_SLUB_DEBUG /* * Determine if we can poison the object itself. If the user of * the slab may touch the object after free or before allocation * then we should never poison the object itself. */ if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) && !s->ctor) s->flags |= __OBJECT_POISON; else s->flags &= ~__OBJECT_POISON; /* * If we are Redzoning then check if there is some space between the * end of the object and the free pointer. If not then add an * additional word to have some bytes to store Redzone information. */ if ((flags & SLAB_RED_ZONE) && size == s->objsize) size += sizeof(void *); #endif /* * With that we have determined the number of bytes in actual use * by the object. This is the potential offset to the free pointer. */ s->inuse = size; if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) || s->ctor)) { /* * Relocate free pointer after the object if it is not * permitted to overwrite the first word of the object on * kmem_cache_free. * * This is the case if we do RCU, have a constructor or * destructor or are poisoning the objects. */ s->offset = size; size += sizeof(void *); } #ifdef CONFIG_SLUB_DEBUG if (flags & SLAB_STORE_USER) /* * Need to store information about allocs and frees after * the object. */ size += 2 * sizeof(struct track); if (flags & SLAB_RED_ZONE) /* * Add some empty padding so that we can catch * overwrites from earlier objects rather than let * tracking information or the free pointer be * corrupted if a user writes before the start * of the object. */ size += sizeof(void *); #endif /* * Determine the alignment based on various parameters that the * user specified and the dynamic determination of cache line size * on bootup. */ align = calculate_alignment(flags, align, s->objsize); s->align = align; /* * SLUB stores one object immediately after another beginning from * offset 0. In order to align the objects we have to simply size * each object to conform to the alignment. */ size = ALIGN(size, align); s->size = size; if (forced_order >= 0) order = forced_order; else order = calculate_order(size); if (order < 0) return 0; s->allocflags = 0; if (order) s->allocflags |= __GFP_COMP; if (s->flags & SLAB_CACHE_DMA) s->allocflags |= SLUB_DMA; if (s->flags & SLAB_RECLAIM_ACCOUNT) s->allocflags |= __GFP_RECLAIMABLE; /* * Determine the number of objects per slab */ s->oo = oo_make(order, size); s->min = oo_make(get_order(size), size); if (oo_objects(s->oo) > oo_objects(s->max)) s->max = s->oo; return !!oo_objects(s->oo); } static int kmem_cache_open(struct kmem_cache *s, const char *name, size_t size, size_t align, unsigned long flags, void (*ctor)(void *)) { memset(s, 0, kmem_size); s->name = name; s->ctor = ctor; s->objsize = size; s->align = align; s->flags = kmem_cache_flags(size, flags, name, ctor); if (!calculate_sizes(s, -1)) goto error; if (disable_higher_order_debug) { /* * Disable debugging flags that store metadata if the min slab * order increased. */ if (get_order(s->size) > get_order(s->objsize)) { s->flags &= ~DEBUG_METADATA_FLAGS; s->offset = 0; if (!calculate_sizes(s, -1)) goto error; } } /* * The larger the object size is, the more pages we want on the partial * list to avoid pounding the page allocator excessively. */ set_min_partial(s, ilog2(s->size)); s->refcount = 1; #ifdef CONFIG_NUMA s->remote_node_defrag_ratio = 1000; #endif if (!init_kmem_cache_nodes(s)) goto error; if (alloc_kmem_cache_cpus(s)) return 1; free_kmem_cache_nodes(s); error: if (flags & SLAB_PANIC) panic("Cannot create slab %s size=%lu realsize=%u " "order=%u offset=%u flags=%lx\n", s->name, (unsigned long)size, s->size, oo_order(s->oo), s->offset, flags); return 0; } /* * Check if a given pointer is valid */ int kmem_ptr_validate(struct kmem_cache *s, const void *object) { struct page *page; if (!kern_ptr_validate(object, s->size)) return 0; page = get_object_page(object); if (!page || s != page->slab) /* No slab or wrong slab */ return 0; if (!check_valid_pointer(s, page, object)) return 0; /* * We could also check if the object is on the slabs freelist. * But this would be too expensive and it seems that the main * purpose of kmem_ptr_valid() is to check if the object belongs * to a certain slab. */ return 1; } EXPORT_SYMBOL(kmem_ptr_validate); /* * Determine the size of a slab object */ unsigned int kmem_cache_size(struct kmem_cache *s) { return s->objsize; } EXPORT_SYMBOL(kmem_cache_size); const char *kmem_cache_name(struct kmem_cache *s) { return s->name; } EXPORT_SYMBOL(kmem_cache_name); static void list_slab_objects(struct kmem_cache *s, struct page *page, const char *text) { #ifdef CONFIG_SLUB_DEBUG void *addr = page_address(page); void *p; unsigned long *map = kzalloc(BITS_TO_LONGS(page->objects) * sizeof(long), GFP_ATOMIC); if (!map) return; slab_err(s, page, "%s", text); slab_lock(page); for_each_free_object(p, s, page->freelist) set_bit(slab_index(p, s, addr), map); for_each_object(p, s, addr, page->objects) { if (!test_bit(slab_index(p, s, addr), map)) { printk(KERN_ERR "INFO: Object 0x%p @offset=%tu\n", p, p - addr); print_tracking(s, p); } } slab_unlock(page); kfree(map); #endif } /* * Attempt to free all partial slabs on a node. */ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n) { unsigned long flags; struct page *page, *h; spin_lock_irqsave(&n->list_lock, flags); list_for_each_entry_safe(page, h, &n->partial, lru) { if (!page->inuse) { __remove_partial(n, page); discard_slab(s, page); } else { list_slab_objects(s, page, "Objects remaining on kmem_cache_close()"); } } spin_unlock_irqrestore(&n->list_lock, flags); } /* * Release all resources used by a slab cache. */ static inline int kmem_cache_close(struct kmem_cache *s) { int node; flush_all(s); free_percpu(s->cpu_slab); /* Attempt to free all objects */ for_each_node_state(node, N_NORMAL_MEMORY) { struct kmem_cache_node *n = get_node(s, node); free_partial(s, n); if (n->nr_partial || slabs_node(s, node)) return 1; } free_kmem_cache_nodes(s); return 0; } /* * Close a cache and release the kmem_cache structure * (must be used for caches created using kmem_cache_create) */ void kmem_cache_destroy(struct kmem_cache *s) { down_write(&slub_lock); s->refcount--; if (!s->refcount) { list_del(&s->list); if (kmem_cache_close(s)) { printk(KERN_ERR "SLUB %s: %s called for cache that " "still has objects.\n", s->name, __func__); dump_stack(); } if (s->flags & SLAB_DESTROY_BY_RCU) rcu_barrier(); sysfs_slab_remove(s); } up_write(&slub_lock); } EXPORT_SYMBOL(kmem_cache_destroy); /******************************************************************** * Kmalloc subsystem *******************************************************************/ struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT]; EXPORT_SYMBOL(kmalloc_caches); static struct kmem_cache *kmem_cache; #ifdef CONFIG_ZONE_DMA static struct kmem_cache *kmalloc_dma_caches[SLUB_PAGE_SHIFT]; #endif static int __init setup_slub_min_order(char *str) { get_option(&str, &slub_min_order); return 1; } __setup("slub_min_order=", setup_slub_min_order); static int __init setup_slub_max_order(char *str) { get_option(&str, &slub_max_order); slub_max_order = min(slub_max_order, MAX_ORDER - 1); return 1; } __setup("slub_max_order=", setup_slub_max_order); static int __init setup_slub_min_objects(char *str) { get_option(&str, &slub_min_objects); return 1; } __setup("slub_min_objects=", setup_slub_min_objects); static int __init setup_slub_nomerge(char *str) { slub_nomerge = 1; return 1; } __setup("slub_nomerge", setup_slub_nomerge); static struct kmem_cache *__init create_kmalloc_cache(const char *name, int size, unsigned int flags) { struct kmem_cache *s; s = kmem_cache_alloc(kmem_cache, GFP_NOWAIT); /* * This function is called with IRQs disabled during early-boot on * single CPU so there's no need to take slub_lock here. */ if (!kmem_cache_open(s, name, size, ARCH_KMALLOC_MINALIGN, flags, NULL)) goto panic; list_add(&s->list, &slab_caches); return s; panic: panic("Creation of kmalloc slab %s size=%d failed.\n", name, size); return NULL; } /* * Conversion table for small slabs sizes / 8 to the index in the * kmalloc array. This is necessary for slabs < 192 since we have non power * of two cache sizes there. The size of larger slabs can be determined using * fls. */ static s8 size_index[24] = { 3, /* 8 */ 4, /* 16 */ 5, /* 24 */ 5, /* 32 */ 6, /* 40 */ 6, /* 48 */ 6, /* 56 */ 6, /* 64 */ 1, /* 72 */ 1, /* 80 */ 1, /* 88 */ 1, /* 96 */ 7, /* 104 */ 7, /* 112 */ 7, /* 120 */ 7, /* 128 */ 2, /* 136 */ 2, /* 144 */ 2, /* 152 */ 2, /* 160 */ 2, /* 168 */ 2, /* 176 */ 2, /* 184 */ 2 /* 192 */ }; static inline int size_index_elem(size_t bytes) { return (bytes - 1) / 8; } static struct kmem_cache *get_slab(size_t size, gfp_t flags) { int index; if (size <= 192) { if (!size) return ZERO_SIZE_PTR; index = size_index[size_index_elem(size)]; } else index = fls(size - 1); #ifdef CONFIG_ZONE_DMA if (unlikely((flags & SLUB_DMA))) return kmalloc_dma_caches[index]; #endif return kmalloc_caches[index]; } void *__kmalloc(size_t size, gfp_t flags) { struct kmem_cache *s; void *ret; if (unlikely(size > SLUB_MAX_SIZE)) return kmalloc_large(size, flags); s = get_slab(size, flags); if (unlikely(ZERO_OR_NULL_PTR(s))) return s; ret = slab_alloc(s, flags, NUMA_NO_NODE, _RET_IP_); trace_kmalloc(_RET_IP_, ret, size, s->size, flags); return ret; } EXPORT_SYMBOL(__kmalloc); #ifdef CONFIG_NUMA static void *kmalloc_large_node(size_t size, gfp_t flags, int node) { struct page *page; void *ptr = NULL; flags |= __GFP_COMP | __GFP_NOTRACK; page = alloc_pages_node(node, flags, get_order(size)); if (page) ptr = page_address(page); kmemleak_alloc(ptr, size, 1, flags); return ptr; } void *__kmalloc_node(size_t size, gfp_t flags, int node) { struct kmem_cache *s; void *ret; if (unlikely(size > SLUB_MAX_SIZE)) { ret = kmalloc_large_node(size, flags, node); trace_kmalloc_node(_RET_IP_, ret, size, PAGE_SIZE << get_order(size), flags, node); return ret; } s = get_slab(size, flags); if (unlikely(ZERO_OR_NULL_PTR(s))) return s; ret = slab_alloc(s, flags, node, _RET_IP_); trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node); return ret; } EXPORT_SYMBOL(__kmalloc_node); #endif size_t ksize(const void *object) { struct page *page; struct kmem_cache *s; if (unlikely(object == ZERO_SIZE_PTR)) return 0; page = virt_to_head_page(object); if (unlikely(!PageSlab(page))) { WARN_ON(!PageCompound(page)); return PAGE_SIZE << compound_order(page); } s = page->slab; #ifdef CONFIG_SLUB_DEBUG /* * Debugging requires use of the padding between object * and whatever may come after it. */ if (s->flags & (SLAB_RED_ZONE | SLAB_POISON)) return s->objsize; #endif /* * If we have the need to store the freelist pointer * back there or track user information then we can * only use the space before that information. */ if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER)) return s->inuse; /* * Else we can use all the padding etc for the allocation */ return s->size; } EXPORT_SYMBOL(ksize); void kfree(const void *x) { struct page *page; void *object = (void *)x; trace_kfree(_RET_IP_, x); if (unlikely(ZERO_OR_NULL_PTR(x))) return; page = virt_to_head_page(x); if (unlikely(!PageSlab(page))) { BUG_ON(!PageCompound(page)); kmemleak_free(x); put_page(page); return; } slab_free(page->slab, page, object, _RET_IP_); } EXPORT_SYMBOL(kfree); /* * kmem_cache_shrink removes empty slabs from the partial lists and sorts * the remaining slabs by the number of items in use. The slabs with the * most items in use come first. New allocations will then fill those up * and thus they can be removed from the partial lists. * * The slabs with the least items are placed last. This results in them * being allocated from last increasing the chance that the last objects * are freed in them. */ int kmem_cache_shrink(struct kmem_cache *s) { int node; int i; struct kmem_cache_node *n; struct page *page; struct page *t; int objects = oo_objects(s->max); struct list_head *slabs_by_inuse = kmalloc(sizeof(struct list_head) * objects, GFP_KERNEL); unsigned long flags; if (!slabs_by_inuse) return -ENOMEM; flush_all(s); for_each_node_state(node, N_NORMAL_MEMORY) { n = get_node(s, node); if (!n->nr_partial) continue; for (i = 0; i < objects; i++) INIT_LIST_HEAD(slabs_by_inuse + i); spin_lock_irqsave(&n->list_lock, flags); /* * Build lists indexed by the items in use in each slab. * * Note that concurrent frees may occur while we hold the * list_lock. page->inuse here is the upper limit. */ list_for_each_entry_safe(page, t, &n->partial, lru) { if (!page->inuse && slab_trylock(page)) { /* * Must hold slab lock here because slab_free * may have freed the last object and be * waiting to release the slab. */ __remove_partial(n, page); slab_unlock(page); discard_slab(s, page); } else { list_move(&page->lru, slabs_by_inuse + page->inuse); } } /* * Rebuild the partial list with the slabs filled up most * first and the least used slabs at the end. */ for (i = objects - 1; i >= 0; i--) list_splice(slabs_by_inuse + i, n->partial.prev); spin_unlock_irqrestore(&n->list_lock, flags); } kfree(slabs_by_inuse); return 0; } EXPORT_SYMBOL(kmem_cache_shrink); #if defined(CONFIG_MEMORY_HOTPLUG) static int slab_mem_going_offline_callback(void *arg) { struct kmem_cache *s; down_read(&slub_lock); list_for_each_entry(s, &slab_caches, list) kmem_cache_shrink(s); up_read(&slub_lock); return 0; } static void slab_mem_offline_callback(void *arg) { struct kmem_cache_node *n; struct kmem_cache *s; struct memory_notify *marg = arg; int offline_node; offline_node = marg->status_change_nid; /* * If the node still has available memory. we need kmem_cache_node * for it yet. */ if (offline_node < 0) return; down_read(&slub_lock); list_for_each_entry(s, &slab_caches, list) { n = get_node(s, offline_node); if (n) { /* * if n->nr_slabs > 0, slabs still exist on the node * that is going down. We were unable to free them, * and offline_pages() function shouldn't call this * callback. So, we must fail. */ BUG_ON(slabs_node(s, offline_node)); s->node[offline_node] = NULL; kmem_cache_free(kmem_cache_node, n); } } up_read(&slub_lock); } static int slab_mem_going_online_callback(void *arg) { struct kmem_cache_node *n; struct kmem_cache *s; struct memory_notify *marg = arg; int nid = marg->status_change_nid; int ret = 0; /* * If the node's memory is already available, then kmem_cache_node is * already created. Nothing to do. */ if (nid < 0) return 0; /* * We are bringing a node online. No memory is available yet. We must * allocate a kmem_cache_node structure in order to bring the node * online. */ down_read(&slub_lock); list_for_each_entry(s, &slab_caches, list) { /* * XXX: kmem_cache_alloc_node will fallback to other nodes * since memory is not yet available from the node that * is brought up. */ n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL); if (!n) { ret = -ENOMEM; goto out; } init_kmem_cache_node(n, s); s->node[nid] = n; } out: up_read(&slub_lock); return ret; } static int slab_memory_callback(struct notifier_block *self, unsigned long action, void *arg) { int ret = 0; switch (action) { case MEM_GOING_ONLINE: ret = slab_mem_going_online_callback(arg); break; case MEM_GOING_OFFLINE: ret = slab_mem_going_offline_callback(arg); break; case MEM_OFFLINE: case MEM_CANCEL_ONLINE: slab_mem_offline_callback(arg); break; case MEM_ONLINE: case MEM_CANCEL_OFFLINE: break; } if (ret) ret = notifier_from_errno(ret); else ret = NOTIFY_OK; return ret; } #endif /* CONFIG_MEMORY_HOTPLUG */ /******************************************************************** * Basic setup of slabs *******************************************************************/ /* * Used for early kmem_cache structures that were allocated using * the page allocator */ static void __init kmem_cache_bootstrap_fixup(struct kmem_cache *s) { int node; list_add(&s->list, &slab_caches); s->refcount = -1; for_each_node_state(node, N_NORMAL_MEMORY) { struct kmem_cache_node *n = get_node(s, node); struct page *p; if (n) { list_for_each_entry(p, &n->partial, lru) p->slab = s; #ifdef CONFIG_SLAB_DEBUG list_for_each_entry(p, &n->full, lru) p->slab = s; #endif } } } void __init kmem_cache_init(void) { int i; int caches = 0; struct kmem_cache *temp_kmem_cache; int order; struct kmem_cache *temp_kmem_cache_node; unsigned long kmalloc_size; kmem_size = offsetof(struct kmem_cache, node) + nr_node_ids * sizeof(struct kmem_cache_node *); /* Allocate two kmem_caches from the page allocator */ kmalloc_size = ALIGN(kmem_size, cache_line_size()); order = get_order(2 * kmalloc_size); kmem_cache = (void *)__get_free_pages(GFP_NOWAIT, order); /* * Must first have the slab cache available for the allocations of the * struct kmem_cache_node's. There is special bootstrap code in * kmem_cache_open for slab_state == DOWN. */ kmem_cache_node = (void *)kmem_cache + kmalloc_size; kmem_cache_open(kmem_cache_node, "kmem_cache_node", sizeof(struct kmem_cache_node), 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL); hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI); /* Able to allocate the per node structures */ slab_state = PARTIAL; temp_kmem_cache = kmem_cache; kmem_cache_open(kmem_cache, "kmem_cache", kmem_size, 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL); kmem_cache = kmem_cache_alloc(kmem_cache, GFP_NOWAIT); memcpy(kmem_cache, temp_kmem_cache, kmem_size); /* * Allocate kmem_cache_node properly from the kmem_cache slab. * kmem_cache_node is separately allocated so no need to * update any list pointers. */ temp_kmem_cache_node = kmem_cache_node; kmem_cache_node = kmem_cache_alloc(kmem_cache, GFP_NOWAIT); memcpy(kmem_cache_node, temp_kmem_cache_node, kmem_size); kmem_cache_bootstrap_fixup(kmem_cache_node); caches++; kmem_cache_bootstrap_fixup(kmem_cache); caches++; /* Free temporary boot structure */ free_pages((unsigned long)temp_kmem_cache, order); /* Now we can use the kmem_cache to allocate kmalloc slabs */ /* * Patch up the size_index table if we have strange large alignment * requirements for the kmalloc array. This is only the case for * MIPS it seems. The standard arches will not generate any code here. * * Largest permitted alignment is 256 bytes due to the way we * handle the index determination for the smaller caches. * * Make sure that nothing crazy happens if someone starts tinkering * around with ARCH_KMALLOC_MINALIGN */ BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 || (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1))); for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) { int elem = size_index_elem(i); if (elem >= ARRAY_SIZE(size_index)) break; size_index[elem] = KMALLOC_SHIFT_LOW; } if (KMALLOC_MIN_SIZE == 64) { /* * The 96 byte size cache is not used if the alignment * is 64 byte. */ for (i = 64 + 8; i <= 96; i += 8) size_index[size_index_elem(i)] = 7; } else if (KMALLOC_MIN_SIZE == 128) { /* * The 192 byte sized cache is not used if the alignment * is 128 byte. Redirect kmalloc to use the 256 byte cache * instead. */ for (i = 128 + 8; i <= 192; i += 8) size_index[size_index_elem(i)] = 8; } /* Caches that are not of the two-to-the-power-of size */ if (KMALLOC_MIN_SIZE <= 32) { kmalloc_caches[1] = create_kmalloc_cache("kmalloc-96", 96, 0); caches++; } if (KMALLOC_MIN_SIZE <= 64) { kmalloc_caches[2] = create_kmalloc_cache("kmalloc-192", 192, 0); caches++; } for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) { kmalloc_caches[i] = create_kmalloc_cache("kmalloc", 1 << i, 0); caches++; } slab_state = UP; /* Provide the correct kmalloc names now that the caches are up */ if (KMALLOC_MIN_SIZE <= 32) { kmalloc_caches[1]->name = kstrdup(kmalloc_caches[1]->name, GFP_NOWAIT); BUG_ON(!kmalloc_caches[1]->name); } if (KMALLOC_MIN_SIZE <= 64) { kmalloc_caches[2]->name = kstrdup(kmalloc_caches[2]->name, GFP_NOWAIT); BUG_ON(!kmalloc_caches[2]->name); } for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) { char *s = kasprintf(GFP_NOWAIT, "kmalloc-%d", 1 << i); BUG_ON(!s); kmalloc_caches[i]->name = s; } #ifdef CONFIG_SMP register_cpu_notifier(&slab_notifier); #endif #ifdef CONFIG_ZONE_DMA for (i = 0; i < SLUB_PAGE_SHIFT; i++) { struct kmem_cache *s = kmalloc_caches[i]; if (s && s->size) { char *name = kasprintf(GFP_NOWAIT, "dma-kmalloc-%d", s->objsize); BUG_ON(!name); kmalloc_dma_caches[i] = create_kmalloc_cache(name, s->objsize, SLAB_CACHE_DMA); } } #endif printk(KERN_INFO "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d," " CPUs=%d, Nodes=%d\n", caches, cache_line_size(), slub_min_order, slub_max_order, slub_min_objects, nr_cpu_ids, nr_node_ids); } void __init kmem_cache_init_late(void) { } /* * Find a mergeable slab cache */ static int slab_unmergeable(struct kmem_cache *s) { if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE)) return 1; if (s->ctor) return 1; /* * We may have set a slab to be unmergeable during bootstrap. */ if (s->refcount < 0) return 1; return 0; } static struct kmem_cache *find_mergeable(size_t size, size_t align, unsigned long flags, const char *name, void (*ctor)(void *)) { struct kmem_cache *s; if (slub_nomerge || (flags & SLUB_NEVER_MERGE)) return NULL; if (ctor) return NULL; size = ALIGN(size, sizeof(void *)); align = calculate_alignment(flags, align, size); size = ALIGN(size, align); flags = kmem_cache_flags(size, flags, name, NULL); list_for_each_entry(s, &slab_caches, list) { if (slab_unmergeable(s)) continue; if (size > s->size) continue; if ((flags & SLUB_MERGE_SAME) != (s->flags & SLUB_MERGE_SAME)) continue; /* * Check if alignment is compatible. * Courtesy of Adrian Drzewiecki */ if ((s->size & ~(align - 1)) != s->size) continue; if (s->size - size >= sizeof(void *)) continue; return s; } return NULL; } struct kmem_cache *kmem_cache_create(const char *name, size_t size, size_t align, unsigned long flags, void (*ctor)(void *)) { struct kmem_cache *s; char *n; if (WARN_ON(!name)) return NULL; down_write(&slub_lock); s = find_mergeable(size, align, flags, name, ctor); if (s) { s->refcount++; /* * Adjust the object sizes so that we clear * the complete object on kzalloc. */ s->objsize = max(s->objsize, (int)size); s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *))); if (sysfs_slab_alias(s, name)) { s->refcount--; goto err; } up_write(&slub_lock); return s; } n = kstrdup(name, GFP_KERNEL); if (!n) goto err; s = kmalloc(kmem_size, GFP_KERNEL); if (s) { if (kmem_cache_open(s, n, size, align, flags, ctor)) { list_add(&s->list, &slab_caches); if (sysfs_slab_add(s)) { list_del(&s->list); kfree(n); kfree(s); goto err; } up_write(&slub_lock); return s; } kfree(n); kfree(s); } err: up_write(&slub_lock); if (flags & SLAB_PANIC) panic("Cannot create slabcache %s\n", name); else s = NULL; return s; } EXPORT_SYMBOL(kmem_cache_create); #ifdef CONFIG_SMP /* * Use the cpu notifier to insure that the cpu slabs are flushed when * necessary. */ static int __cpuinit slab_cpuup_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) { long cpu = (long)hcpu; struct kmem_cache *s; unsigned long flags; switch (action) { case CPU_UP_CANCELED: case CPU_UP_CANCELED_FROZEN: case CPU_DEAD: case CPU_DEAD_FROZEN: down_read(&slub_lock); list_for_each_entry(s, &slab_caches, list) { local_irq_save(flags); __flush_cpu_slab(s, cpu); local_irq_restore(flags); } up_read(&slub_lock); break; default: break; } return NOTIFY_OK; } static struct notifier_block __cpuinitdata slab_notifier = { .notifier_call = slab_cpuup_callback }; #endif void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller) { struct kmem_cache *s; void *ret; if (unlikely(size > SLUB_MAX_SIZE)) return kmalloc_large(size, gfpflags); s = get_slab(size, gfpflags); if (unlikely(ZERO_OR_NULL_PTR(s))) return s; ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, caller); /* Honor the call site pointer we recieved. */ trace_kmalloc(caller, ret, size, s->size, gfpflags); return ret; } #ifdef CONFIG_NUMA void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags, int node, unsigned long caller) { struct kmem_cache *s; void *ret; if (unlikely(size > SLUB_MAX_SIZE)) { ret = kmalloc_large_node(size, gfpflags, node); trace_kmalloc_node(caller, ret, size, PAGE_SIZE << get_order(size), gfpflags, node); return ret; } s = get_slab(size, gfpflags); if (unlikely(ZERO_OR_NULL_PTR(s))) return s; ret = slab_alloc(s, gfpflags, node, caller); /* Honor the call site pointer we recieved. */ trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node); return ret; } #endif #ifdef CONFIG_SYSFS static int count_inuse(struct page *page) { return page->inuse; } static int count_total(struct page *page) { return page->objects; } #endif #ifdef CONFIG_SLUB_DEBUG static int validate_slab(struct kmem_cache *s, struct page *page, unsigned long *map) { void *p; void *addr = page_address(page); if (!check_slab(s, page) || !on_freelist(s, page, NULL)) return 0; /* Now we know that a valid freelist exists */ bitmap_zero(map, page->objects); for_each_free_object(p, s, page->freelist) { set_bit(slab_index(p, s, addr), map); if (!check_object(s, page, p, 0)) return 0; } for_each_object(p, s, addr, page->objects) if (!test_bit(slab_index(p, s, addr), map)) if (!check_object(s, page, p, 1)) return 0; return 1; } static void validate_slab_slab(struct kmem_cache *s, struct page *page, unsigned long *map) { if (slab_trylock(page)) { validate_slab(s, page, map); slab_unlock(page); } else printk(KERN_INFO "SLUB %s: Skipped busy slab 0x%p\n", s->name, page); } static int validate_slab_node(struct kmem_cache *s, struct kmem_cache_node *n, unsigned long *map) { unsigned long count = 0; struct page *page; unsigned long flags; spin_lock_irqsave(&n->list_lock, flags); list_for_each_entry(page, &n->partial, lru) { validate_slab_slab(s, page, map); count++; } if (count != n->nr_partial) printk(KERN_ERR "SLUB %s: %ld partial slabs counted but " "counter=%ld\n", s->name, count, n->nr_partial); if (!(s->flags & SLAB_STORE_USER)) goto out; list_for_each_entry(page, &n->full, lru) { validate_slab_slab(s, page, map); count++; } if (count != atomic_long_read(&n->nr_slabs)) printk(KERN_ERR "SLUB: %s %ld slabs counted but " "counter=%ld\n", s->name, count, atomic_long_read(&n->nr_slabs)); out: spin_unlock_irqrestore(&n->list_lock, flags); return count; } static long validate_slab_cache(struct kmem_cache *s) { int node; unsigned long count = 0; unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) * sizeof(unsigned long), GFP_KERNEL); if (!map) return -ENOMEM; flush_all(s); for_each_node_state(node, N_NORMAL_MEMORY) { struct kmem_cache_node *n = get_node(s, node); count += validate_slab_node(s, n, map); } kfree(map); return count; } /* * Generate lists of code addresses where slabcache objects are allocated * and freed. */ struct location { unsigned long count; unsigned long addr; long long sum_time; long min_time; long max_time; long min_pid; long max_pid; DECLARE_BITMAP(cpus, NR_CPUS); nodemask_t nodes; }; struct loc_track { unsigned long max; unsigned long count; struct location *loc; }; static void free_loc_track(struct loc_track *t) { if (t->max) free_pages((unsigned long)t->loc, get_order(sizeof(struct location) * t->max)); } static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags) { struct location *l; int order; order = get_order(sizeof(struct location) * max); l = (void *)__get_free_pages(flags, order); if (!l) return 0; if (t->count) { memcpy(l, t->loc, sizeof(struct location) * t->count); free_loc_track(t); } t->max = max; t->loc = l; return 1; } static int add_location(struct loc_track *t, struct kmem_cache *s, const struct track *track) { long start, end, pos; struct location *l; unsigned long caddr; unsigned long age = jiffies - track->when; start = -1; end = t->count; for ( ; ; ) { pos = start + (end - start + 1) / 2; /* * There is nothing at "end". If we end up there * we need to add something to before end. */ if (pos == end) break; caddr = t->loc[pos].addr; if (track->addr == caddr) { l = &t->loc[pos]; l->count++; if (track->when) { l->sum_time += age; if (age < l->min_time) l->min_time = age; if (age > l->max_time) l->max_time = age; if (track->pid < l->min_pid) l->min_pid = track->pid; if (track->pid > l->max_pid) l->max_pid = track->pid; cpumask_set_cpu(track->cpu, to_cpumask(l->cpus)); } node_set(page_to_nid(virt_to_page(track)), l->nodes); return 1; } if (track->addr < caddr) end = pos; else start = pos; } /* * Not found. Insert new tracking element. */ if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC)) return 0; l = t->loc + pos; if (pos < t->count) memmove(l + 1, l, (t->count - pos) * sizeof(struct location)); t->count++; l->count = 1; l->addr = track->addr; l->sum_time = age; l->min_time = age; l->max_time = age; l->min_pid = track->pid; l->max_pid = track->pid; cpumask_clear(to_cpumask(l->cpus)); cpumask_set_cpu(track->cpu, to_cpumask(l->cpus)); nodes_clear(l->nodes); node_set(page_to_nid(virt_to_page(track)), l->nodes); return 1; } static void process_slab(struct loc_track *t, struct kmem_cache *s, struct page *page, enum track_item alloc, unsigned long *map) { void *addr = page_address(page); void *p; bitmap_zero(map, page->objects); for_each_free_object(p, s, page->freelist) set_bit(slab_index(p, s, addr), map); for_each_object(p, s, addr, page->objects) if (!test_bit(slab_index(p, s, addr), map)) add_location(t, s, get_track(s, p, alloc)); } static int list_locations(struct kmem_cache *s, char *buf, enum track_item alloc) { int len = 0; unsigned long i; struct loc_track t = { 0, 0, NULL }; int node; unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) * sizeof(unsigned long), GFP_KERNEL); if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location), GFP_TEMPORARY)) { kfree(map); return sprintf(buf, "Out of memory\n"); } /* Push back cpu slabs */ flush_all(s); for_each_node_state(node, N_NORMAL_MEMORY) { struct kmem_cache_node *n = get_node(s, node); unsigned long flags; struct page *page; if (!atomic_long_read(&n->nr_slabs)) continue; spin_lock_irqsave(&n->list_lock, flags); list_for_each_entry(page, &n->partial, lru) process_slab(&t, s, page, alloc, map); list_for_each_entry(page, &n->full, lru) process_slab(&t, s, page, alloc, map); spin_unlock_irqrestore(&n->list_lock, flags); } for (i = 0; i < t.count; i++) { struct location *l = &t.loc[i]; if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100) break; len += sprintf(buf + len, "%7ld ", l->count); if (l->addr) len += sprint_symbol(buf + len, (unsigned long)l->addr); else len += sprintf(buf + len, "<not-available>"); if (l->sum_time != l->min_time) { len += sprintf(buf + len, " age=%ld/%ld/%ld", l->min_time, (long)div_u64(l->sum_time, l->count), l->max_time); } else len += sprintf(buf + len, " age=%ld", l->min_time); if (l->min_pid != l->max_pid) len += sprintf(buf + len, " pid=%ld-%ld", l->min_pid, l->max_pid); else len += sprintf(buf + len, " pid=%ld", l->min_pid); if (num_online_cpus() > 1 && !cpumask_empty(to_cpumask(l->cpus)) && len < PAGE_SIZE - 60) { len += sprintf(buf + len, " cpus="); len += cpulist_scnprintf(buf + len, PAGE_SIZE - len - 50, to_cpumask(l->cpus)); } if (nr_online_nodes > 1 && !nodes_empty(l->nodes) && len < PAGE_SIZE - 60) { len += sprintf(buf + len, " nodes="); len += nodelist_scnprintf(buf + len, PAGE_SIZE - len - 50, l->nodes); } len += sprintf(buf + len, "\n"); } free_loc_track(&t); kfree(map); if (!t.count) len += sprintf(buf, "No data\n"); return len; } #endif #ifdef SLUB_RESILIENCY_TEST static void resiliency_test(void) { u8 *p; BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || SLUB_PAGE_SHIFT < 10); printk(KERN_ERR "SLUB resiliency testing\n"); printk(KERN_ERR "-----------------------\n"); printk(KERN_ERR "A. Corruption after allocation\n"); p = kzalloc(16, GFP_KERNEL); p[16] = 0x12; printk(KERN_ERR "\n1. kmalloc-16: Clobber Redzone/next pointer" " 0x12->0x%p\n\n", p + 16); validate_slab_cache(kmalloc_caches[4]); /* Hmmm... The next two are dangerous */ p = kzalloc(32, GFP_KERNEL); p[32 + sizeof(void *)] = 0x34; printk(KERN_ERR "\n2. kmalloc-32: Clobber next pointer/next slab" " 0x34 -> -0x%p\n", p); printk(KERN_ERR "If allocated object is overwritten then not detectable\n\n"); validate_slab_cache(kmalloc_caches[5]); p = kzalloc(64, GFP_KERNEL); p += 64 + (get_cycles() & 0xff) * sizeof(void *); *p = 0x56; printk(KERN_ERR "\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n", p); printk(KERN_ERR "If allocated object is overwritten then not detectable\n\n"); validate_slab_cache(kmalloc_caches[6]); printk(KERN_ERR "\nB. Corruption after free\n"); p = kzalloc(128, GFP_KERNEL); kfree(p); *p = 0x78; printk(KERN_ERR "1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p); validate_slab_cache(kmalloc_caches[7]); p = kzalloc(256, GFP_KERNEL); kfree(p); p[50] = 0x9a; printk(KERN_ERR "\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p); validate_slab_cache(kmalloc_caches[8]); p = kzalloc(512, GFP_KERNEL); kfree(p); p[512] = 0xab; printk(KERN_ERR "\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p); validate_slab_cache(kmalloc_caches[9]); } #else #ifdef CONFIG_SYSFS static void resiliency_test(void) {}; #endif #endif #ifdef CONFIG_SYSFS enum slab_stat_type { SL_ALL, /* All slabs */ SL_PARTIAL, /* Only partially allocated slabs */ SL_CPU, /* Only slabs used for cpu caches */ SL_OBJECTS, /* Determine allocated objects not slabs */ SL_TOTAL /* Determine object capacity not slabs */ }; #define SO_ALL (1 << SL_ALL) #define SO_PARTIAL (1 << SL_PARTIAL) #define SO_CPU (1 << SL_CPU) #define SO_OBJECTS (1 << SL_OBJECTS) #define SO_TOTAL (1 << SL_TOTAL) static ssize_t show_slab_objects(struct kmem_cache *s, char *buf, unsigned long flags) { unsigned long total = 0; int node; int x; unsigned long *nodes; unsigned long *per_cpu; nodes = kzalloc(2 * sizeof(unsigned long) * nr_node_ids, GFP_KERNEL); if (!nodes) return -ENOMEM; per_cpu = nodes + nr_node_ids; if (flags & SO_CPU) { int cpu; for_each_possible_cpu(cpu) { struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu); if (!c || c->node < 0) continue; if (c->page) { if (flags & SO_TOTAL) x = c->page->objects; else if (flags & SO_OBJECTS) x = c->page->inuse; else x = 1; total += x; nodes[c->node] += x; } per_cpu[c->node]++; } } down_read(&slub_lock); #ifdef CONFIG_SLUB_DEBUG if (flags & SO_ALL) { for_each_node_state(node, N_NORMAL_MEMORY) { struct kmem_cache_node *n = get_node(s, node); if (flags & SO_TOTAL) x = atomic_long_read(&n->total_objects); else if (flags & SO_OBJECTS) x = atomic_long_read(&n->total_objects) - count_partial(n, count_free); else x = atomic_long_read(&n->nr_slabs); total += x; nodes[node] += x; } } else #endif if (flags & SO_PARTIAL) { for_each_node_state(node, N_NORMAL_MEMORY) { struct kmem_cache_node *n = get_node(s, node); if (flags & SO_TOTAL) x = count_partial(n, count_total); else if (flags & SO_OBJECTS) x = count_partial(n, count_inuse); else x = n->nr_partial; total += x; nodes[node] += x; } } x = sprintf(buf, "%lu", total); #ifdef CONFIG_NUMA for_each_node_state(node, N_NORMAL_MEMORY) if (nodes[node]) x += sprintf(buf + x, " N%d=%lu", node, nodes[node]); #endif up_read(&slub_lock); kfree(nodes); return x + sprintf(buf + x, "\n"); } #ifdef CONFIG_SLUB_DEBUG static int any_slab_objects(struct kmem_cache *s) { int node; for_each_online_node(node) { struct kmem_cache_node *n = get_node(s, node); if (!n) continue; if (atomic_long_read(&n->total_objects)) return 1; } return 0; } #endif #define to_slab_attr(n) container_of(n, struct slab_attribute, attr) #define to_slab(n) container_of(n, struct kmem_cache, kobj); struct slab_attribute { struct attribute attr; ssize_t (*show)(struct kmem_cache *s, char *buf); ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count); }; #define SLAB_ATTR_RO(_name) \ static struct slab_attribute _name##_attr = __ATTR_RO(_name) #define SLAB_ATTR(_name) \ static struct slab_attribute _name##_attr = \ __ATTR(_name, 0644, _name##_show, _name##_store) static ssize_t slab_size_show(struct kmem_cache *s, char *buf) { return sprintf(buf, "%d\n", s->size); } SLAB_ATTR_RO(slab_size); static ssize_t align_show(struct kmem_cache *s, char *buf) { return sprintf(buf, "%d\n", s->align); } SLAB_ATTR_RO(align); static ssize_t object_size_show(struct kmem_cache *s, char *buf) { return sprintf(buf, "%d\n", s->objsize); } SLAB_ATTR_RO(object_size); static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf) { return sprintf(buf, "%d\n", oo_objects(s->oo)); } SLAB_ATTR_RO(objs_per_slab); static ssize_t order_store(struct kmem_cache *s, const char *buf, size_t length) { unsigned long order; int err; err = strict_strtoul(buf, 10, &order); if (err) return err; if (order > slub_max_order || order < slub_min_order) return -EINVAL; calculate_sizes(s, order); return length; } static ssize_t order_show(struct kmem_cache *s, char *buf) { return sprintf(buf, "%d\n", oo_order(s->oo)); } SLAB_ATTR(order); static ssize_t min_partial_show(struct kmem_cache *s, char *buf) { return sprintf(buf, "%lu\n", s->min_partial); } static ssize_t min_partial_store(struct kmem_cache *s, const char *buf, size_t length) { unsigned long min; int err; err = strict_strtoul(buf, 10, &min); if (err) return err; set_min_partial(s, min); return length; } SLAB_ATTR(min_partial); static ssize_t ctor_show(struct kmem_cache *s, char *buf) { if (s->ctor) { int n = sprint_symbol(buf, (unsigned long)s->ctor); return n + sprintf(buf + n, "\n"); } return 0; } SLAB_ATTR_RO(ctor); static ssize_t aliases_show(struct kmem_cache *s, char *buf) { return sprintf(buf, "%d\n", s->refcount - 1); } SLAB_ATTR_RO(aliases); static ssize_t partial_show(struct kmem_cache *s, char *buf) { return show_slab_objects(s, buf, SO_PARTIAL); } SLAB_ATTR_RO(partial); static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf) { return show_slab_objects(s, buf, SO_CPU); } SLAB_ATTR_RO(cpu_slabs); static ssize_t objects_show(struct kmem_cache *s, char *buf) { return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS); } SLAB_ATTR_RO(objects); static ssize_t objects_partial_show(struct kmem_cache *s, char *buf) { return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS); } SLAB_ATTR_RO(objects_partial); static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf) { return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT)); } static ssize_t reclaim_account_store(struct kmem_cache *s, const char *buf, size_t length) { s->flags &= ~SLAB_RECLAIM_ACCOUNT; if (buf[0] == '1') s->flags |= SLAB_RECLAIM_ACCOUNT; return length; } SLAB_ATTR(reclaim_account); static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf) { return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN)); } SLAB_ATTR_RO(hwcache_align); #ifdef CONFIG_ZONE_DMA static ssize_t cache_dma_show(struct kmem_cache *s, char *buf) { return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA)); } SLAB_ATTR_RO(cache_dma); #endif static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf) { return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU)); } SLAB_ATTR_RO(destroy_by_rcu); #ifdef CONFIG_SLUB_DEBUG static ssize_t slabs_show(struct kmem_cache *s, char *buf) { return show_slab_objects(s, buf, SO_ALL); } SLAB_ATTR_RO(slabs); static ssize_t total_objects_show(struct kmem_cache *s, char *buf) { return show_slab_objects(s, buf, SO_ALL|SO_TOTAL); } SLAB_ATTR_RO(total_objects); static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf) { return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE)); } static ssize_t sanity_checks_store(struct kmem_cache *s, const char *buf, size_t length) { s->flags &= ~SLAB_DEBUG_FREE; if (buf[0] == '1') s->flags |= SLAB_DEBUG_FREE; return length; } SLAB_ATTR(sanity_checks); static ssize_t trace_show(struct kmem_cache *s, char *buf) { return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE)); } static ssize_t trace_store(struct kmem_cache *s, const char *buf, size_t length) { s->flags &= ~SLAB_TRACE; if (buf[0] == '1') s->flags |= SLAB_TRACE; return length; } SLAB_ATTR(trace); static ssize_t red_zone_show(struct kmem_cache *s, char *buf) { return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE)); } static ssize_t red_zone_store(struct kmem_cache *s, const char *buf, size_t length) { if (any_slab_objects(s)) return -EBUSY; s->flags &= ~SLAB_RED_ZONE; if (buf[0] == '1') s->flags |= SLAB_RED_ZONE; calculate_sizes(s, -1); return length; } SLAB_ATTR(red_zone); static ssize_t poison_show(struct kmem_cache *s, char *buf) { return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON)); } static ssize_t poison_store(struct kmem_cache *s, const char *buf, size_t length) { if (any_slab_objects(s)) return -EBUSY; s->flags &= ~SLAB_POISON; if (buf[0] == '1') s->flags |= SLAB_POISON; calculate_sizes(s, -1); return length; } SLAB_ATTR(poison); static ssize_t store_user_show(struct kmem_cache *s, char *buf) { return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER)); } static ssize_t store_user_store(struct kmem_cache *s, const char *buf, size_t length) { if (any_slab_objects(s)) return -EBUSY; s->flags &= ~SLAB_STORE_USER; if (buf[0] == '1') s->flags |= SLAB_STORE_USER; calculate_sizes(s, -1); return length; } SLAB_ATTR(store_user); static ssize_t validate_show(struct kmem_cache *s, char *buf) { return 0; } static ssize_t validate_store(struct kmem_cache *s, const char *buf, size_t length) { int ret = -EINVAL; if (buf[0] == '1') { ret = validate_slab_cache(s); if (ret >= 0) ret = length; } return ret; } SLAB_ATTR(validate); static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf) { if (!(s->flags & SLAB_STORE_USER)) return -ENOSYS; return list_locations(s, buf, TRACK_ALLOC); } SLAB_ATTR_RO(alloc_calls); static ssize_t free_calls_show(struct kmem_cache *s, char *buf) { if (!(s->flags & SLAB_STORE_USER)) return -ENOSYS; return list_locations(s, buf, TRACK_FREE); } SLAB_ATTR_RO(free_calls); #endif /* CONFIG_SLUB_DEBUG */ #ifdef CONFIG_FAILSLAB static ssize_t failslab_show(struct kmem_cache *s, char *buf) { return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB)); } static ssize_t failslab_store(struct kmem_cache *s, const char *buf, size_t length) { s->flags &= ~SLAB_FAILSLAB; if (buf[0] == '1') s->flags |= SLAB_FAILSLAB; return length; } SLAB_ATTR(failslab); #endif static ssize_t shrink_show(struct kmem_cache *s, char *buf) { return 0; } static ssize_t shrink_store(struct kmem_cache *s, const char *buf, size_t length) { if (buf[0] == '1') { int rc = kmem_cache_shrink(s); if (rc) return rc; } else return -EINVAL; return length; } SLAB_ATTR(shrink); #ifdef CONFIG_NUMA static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf) { return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10); } static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s, const char *buf, size_t length) { unsigned long ratio; int err; err = strict_strtoul(buf, 10, &ratio); if (err) return err; if (ratio <= 100) s->remote_node_defrag_ratio = ratio * 10; return length; } SLAB_ATTR(remote_node_defrag_ratio); #endif #ifdef CONFIG_SLUB_STATS static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si) { unsigned long sum = 0; int cpu; int len; int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL); if (!data) return -ENOMEM; for_each_online_cpu(cpu) { unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si]; data[cpu] = x; sum += x; } len = sprintf(buf, "%lu", sum); #ifdef CONFIG_SMP for_each_online_cpu(cpu) { if (data[cpu] && len < PAGE_SIZE - 20) len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]); } #endif kfree(data); return len + sprintf(buf + len, "\n"); } static void clear_stat(struct kmem_cache *s, enum stat_item si) { int cpu; for_each_online_cpu(cpu) per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0; } #define STAT_ATTR(si, text) \ static ssize_t text##_show(struct kmem_cache *s, char *buf) \ { \ return show_stat(s, buf, si); \ } \ static ssize_t text##_store(struct kmem_cache *s, \ const char *buf, size_t length) \ { \ if (buf[0] != '0') \ return -EINVAL; \ clear_stat(s, si); \ return length; \ } \ SLAB_ATTR(text); \ STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath); STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath); STAT_ATTR(FREE_FASTPATH, free_fastpath); STAT_ATTR(FREE_SLOWPATH, free_slowpath); STAT_ATTR(FREE_FROZEN, free_frozen); STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial); STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial); STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial); STAT_ATTR(ALLOC_SLAB, alloc_slab); STAT_ATTR(ALLOC_REFILL, alloc_refill); STAT_ATTR(FREE_SLAB, free_slab); STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush); STAT_ATTR(DEACTIVATE_FULL, deactivate_full); STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty); STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head); STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail); STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees); STAT_ATTR(ORDER_FALLBACK, order_fallback); #endif static struct attribute *slab_attrs[] = { &slab_size_attr.attr, &object_size_attr.attr, &objs_per_slab_attr.attr, &order_attr.attr, &min_partial_attr.attr, &objects_attr.attr, &objects_partial_attr.attr, &partial_attr.attr, &cpu_slabs_attr.attr, &ctor_attr.attr, &aliases_attr.attr, &align_attr.attr, &hwcache_align_attr.attr, &reclaim_account_attr.attr, &destroy_by_rcu_attr.attr, &shrink_attr.attr, #ifdef CONFIG_SLUB_DEBUG &total_objects_attr.attr, &slabs_attr.attr, &sanity_checks_attr.attr, &trace_attr.attr, &red_zone_attr.attr, &poison_attr.attr, &store_user_attr.attr, &validate_attr.attr, &alloc_calls_attr.attr, &free_calls_attr.attr, #endif #ifdef CONFIG_ZONE_DMA &cache_dma_attr.attr, #endif #ifdef CONFIG_NUMA &remote_node_defrag_ratio_attr.attr, #endif #ifdef CONFIG_SLUB_STATS &alloc_fastpath_attr.attr, &alloc_slowpath_attr.attr, &free_fastpath_attr.attr, &free_slowpath_attr.attr, &free_frozen_attr.attr, &free_add_partial_attr.attr, &free_remove_partial_attr.attr, &alloc_from_partial_attr.attr, &alloc_slab_attr.attr, &alloc_refill_attr.attr, &free_slab_attr.attr, &cpuslab_flush_attr.attr, &deactivate_full_attr.attr, &deactivate_empty_attr.attr, &deactivate_to_head_attr.attr, &deactivate_to_tail_attr.attr, &deactivate_remote_frees_attr.attr, &order_fallback_attr.attr, #endif #ifdef CONFIG_FAILSLAB &failslab_attr.attr, #endif NULL }; static struct attribute_group slab_attr_group = { .attrs = slab_attrs, }; static ssize_t slab_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) { struct slab_attribute *attribute; struct kmem_cache *s; int err; attribute = to_slab_attr(attr); s = to_slab(kobj); if (!attribute->show) return -EIO; err = attribute->show(s, buf); return err; } static ssize_t slab_attr_store(struct kobject *kobj, struct attribute *attr, const char *buf, size_t len) { struct slab_attribute *attribute; struct kmem_cache *s; int err; attribute = to_slab_attr(attr); s = to_slab(kobj); if (!attribute->store) return -EIO; err = attribute->store(s, buf, len); return err; } static void kmem_cache_release(struct kobject *kobj) { struct kmem_cache *s = to_slab(kobj); kfree(s->name); kfree(s); } static const struct sysfs_ops slab_sysfs_ops = { .show = slab_attr_show, .store = slab_attr_store, }; static struct kobj_type slab_ktype = { .sysfs_ops = &slab_sysfs_ops, .release = kmem_cache_release }; static int uevent_filter(struct kset *kset, struct kobject *kobj) { struct kobj_type *ktype = get_ktype(kobj); if (ktype == &slab_ktype) return 1; return 0; } static const struct kset_uevent_ops slab_uevent_ops = { .filter = uevent_filter, }; static struct kset *slab_kset; #define ID_STR_LENGTH 64 /* Create a unique string id for a slab cache: * * Format :[flags-]size */ static char *create_unique_id(struct kmem_cache *s) { char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL); char *p = name; BUG_ON(!name); *p++ = ':'; /* * First flags affecting slabcache operations. We will only * get here for aliasable slabs so we do not need to support * too many flags. The flags here must cover all flags that * are matched during merging to guarantee that the id is * unique. */ if (s->flags & SLAB_CACHE_DMA) *p++ = 'd'; if (s->flags & SLAB_RECLAIM_ACCOUNT) *p++ = 'a'; if (s->flags & SLAB_DEBUG_FREE) *p++ = 'F'; if (!(s->flags & SLAB_NOTRACK)) *p++ = 't'; if (p != name + 1) *p++ = '-'; p += sprintf(p, "%07d", s->size); BUG_ON(p > name + ID_STR_LENGTH - 1); return name; } static int sysfs_slab_add(struct kmem_cache *s) { int err; const char *name; int unmergeable; if (slab_state < SYSFS) /* Defer until later */ return 0; unmergeable = slab_unmergeable(s); if (unmergeable) { /* * Slabcache can never be merged so we can use the name proper. * This is typically the case for debug situations. In that * case we can catch duplicate names easily. */ sysfs_remove_link(&slab_kset->kobj, s->name); name = s->name; } else { /* * Create a unique name for the slab as a target * for the symlinks. */ name = create_unique_id(s); } s->kobj.kset = slab_kset; err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, name); if (err) { kobject_put(&s->kobj); return err; } err = sysfs_create_group(&s->kobj, &slab_attr_group); if (err) { kobject_del(&s->kobj); kobject_put(&s->kobj); return err; } kobject_uevent(&s->kobj, KOBJ_ADD); if (!unmergeable) { /* Setup first alias */ sysfs_slab_alias(s, s->name); kfree(name); } return 0; } static void sysfs_slab_remove(struct kmem_cache *s) { if (slab_state < SYSFS) /* * Sysfs has not been setup yet so no need to remove the * cache from sysfs. */ return; kobject_uevent(&s->kobj, KOBJ_REMOVE); kobject_del(&s->kobj); kobject_put(&s->kobj); } /* * Need to buffer aliases during bootup until sysfs becomes * available lest we lose that information. */ struct saved_alias { struct kmem_cache *s; const char *name; struct saved_alias *next; }; static struct saved_alias *alias_list; static int sysfs_slab_alias(struct kmem_cache *s, const char *name) { struct saved_alias *al; if (slab_state == SYSFS) { /* * If we have a leftover link then remove it. */ sysfs_remove_link(&slab_kset->kobj, name); return sysfs_create_link(&slab_kset->kobj, &s->kobj, name); } al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL); if (!al) return -ENOMEM; al->s = s; al->name = name; al->next = alias_list; alias_list = al; return 0; } static int __init slab_sysfs_init(void) { struct kmem_cache *s; int err; down_write(&slub_lock); slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj); if (!slab_kset) { up_write(&slub_lock); printk(KERN_ERR "Cannot register slab subsystem.\n"); return -ENOSYS; } slab_state = SYSFS; list_for_each_entry(s, &slab_caches, list) { err = sysfs_slab_add(s); if (err) printk(KERN_ERR "SLUB: Unable to add boot slab %s" " to sysfs\n", s->name); } while (alias_list) { struct saved_alias *al = alias_list; alias_list = alias_list->next; err = sysfs_slab_alias(al->s, al->name); if (err) printk(KERN_ERR "SLUB: Unable to add boot slab alias" " %s to sysfs\n", s->name); kfree(al); } up_write(&slub_lock); resiliency_test(); return 0; } __initcall(slab_sysfs_init); #endif /* CONFIG_SYSFS */ /* * The /proc/slabinfo ABI */ #ifdef CONFIG_SLABINFO static void print_slabinfo_header(struct seq_file *m) { seq_puts(m, "slabinfo - version: 2.1\n"); seq_puts(m, "# name <active_objs> <num_objs> <objsize> " "<objperslab> <pagesperslab>"); seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>"); seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>"); seq_putc(m, '\n'); } static void *s_start(struct seq_file *m, loff_t *pos) { loff_t n = *pos; down_read(&slub_lock); if (!n) print_slabinfo_header(m); return seq_list_start(&slab_caches, *pos); } static void *s_next(struct seq_file *m, void *p, loff_t *pos) { return seq_list_next(p, &slab_caches, pos); } static void s_stop(struct seq_file *m, void *p) { up_read(&slub_lock); } static int s_show(struct seq_file *m, void *p) { unsigned long nr_partials = 0; unsigned long nr_slabs = 0; unsigned long nr_inuse = 0; unsigned long nr_objs = 0; unsigned long nr_free = 0; struct kmem_cache *s; int node; s = list_entry(p, struct kmem_cache, list); for_each_online_node(node) { struct kmem_cache_node *n = get_node(s, node); if (!n) continue; nr_partials += n->nr_partial; nr_slabs += atomic_long_read(&n->nr_slabs); nr_objs += atomic_long_read(&n->total_objects); nr_free += count_partial(n, count_free); } nr_inuse = nr_objs - nr_free; seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", s->name, nr_inuse, nr_objs, s->size, oo_objects(s->oo), (1 << oo_order(s->oo))); seq_printf(m, " : tunables %4u %4u %4u", 0, 0, 0); seq_printf(m, " : slabdata %6lu %6lu %6lu", nr_slabs, nr_slabs, 0UL); seq_putc(m, '\n'); return 0; } static const struct seq_operations slabinfo_op = { .start = s_start, .next = s_next, .stop = s_stop, .show = s_show, }; static int slabinfo_open(struct inode *inode, struct file *file) { return seq_open(file, &slabinfo_op); } static const struct file_operations proc_slabinfo_operations = { .open = slabinfo_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release, }; static int __init slab_proc_init(void) { proc_create("slabinfo", S_IRUGO, NULL, &proc_slabinfo_operations); return 0; } module_init(slab_proc_init); #endif /* CONFIG_SLABINFO */