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

diff options

Diffstat (limited to 'block/blktrace.c')

-rw-r--r--

1 files changed, 45 insertions, 12 deletions


diff --git a/block/blktrace.c b/block/blktrace.c index 135593c8e45b..562ca7cbf858 100644 --- a/block/blktrace.c +++ b/block/blktrace.c
@@ -22,30 +22,61 @@
22	#include <linux/init.h>	22	#include <linux/init.h>
23	#include <linux/mutex.h>	23	#include <linux/mutex.h>
24	#include <linux/debugfs.h>	24	#include <linux/debugfs.h>
		25	#include <linux/time.h>
25	#include <asm/uaccess.h>	26	#include <asm/uaccess.h>
26		27
27	static DEFINE_PER_CPU(unsigned long long, blk_trace_cpu_offset) = { 0, };	28	static DEFINE_PER_CPU(unsigned long long, blk_trace_cpu_offset) = { 0, };
28	static unsigned int blktrace_seq __read_mostly = 1;	29	static unsigned int blktrace_seq __read_mostly = 1;
29		30
30	/*	31	/*
		32	* Send out a notify message.
		33	*/
		34	static inline unsigned int trace_note(struct blk_trace *bt,
		35	pid_t pid, int action,
		36	const void *data, size_t len)
		37	{
		38	struct blk_io_trace *t;
		39	int cpu = smp_processor_id();
		40
		41	t = relay_reserve(bt->rchan, sizeof(*t) + len);
		42	if (t == NULL)
		43	return 0;
		44
		45	t->magic = BLK_IO_TRACE_MAGIC \| BLK_IO_TRACE_VERSION;
		46	t->time = sched_clock() - per_cpu(blk_trace_cpu_offset, cpu);
		47	t->device = bt->dev;
		48	t->action = action;
		49	t->pid = pid;
		50	t->cpu = cpu;
		51	t->pdu_len = len;
		52	memcpy((void ) t + sizeof(t), data, len);
		53	return blktrace_seq;
		54	}
		55
		56	/*
31	* Send out a notify for this process, if we haven't done so since a trace	57	* Send out a notify for this process, if we haven't done so since a trace
32	* started	58	* started
33	*/	59	*/
34	static void trace_note_tsk(struct blk_trace bt, struct task_struct tsk)	60	static void trace_note_tsk(struct blk_trace bt, struct task_struct tsk)
35	{	61	{
36	struct blk_io_trace *t;	62	tsk->btrace_seq = trace_note(bt, tsk->pid,
		63	BLK_TN_PROCESS,
		64	tsk->comm, sizeof(tsk->comm));
		65	}
37		66
38	t = relay_reserve(bt->rchan, sizeof(*t) + sizeof(tsk->comm));	67	static void trace_note_time(struct blk_trace *bt)
39	if (t) {	68	{
40	t->magic = BLK_IO_TRACE_MAGIC \| BLK_IO_TRACE_VERSION;	69	struct timespec now;
41	t->device = bt->dev;	70	unsigned long flags;
42	t->action = BLK_TC_ACT(BLK_TC_NOTIFY);	71	u32 words[2];
43	t->pid = tsk->pid;	72
44	t->cpu = smp_processor_id();	73	getnstimeofday(&now);
45	t->pdu_len = sizeof(tsk->comm);	74	words[0] = now.tv_sec;
46	memcpy((void ) t + sizeof(t), tsk->comm, t->pdu_len);	75	words[1] = now.tv_nsec;
47	tsk->btrace_seq = blktrace_seq;	76
48	}	77	local_irq_save(flags);
		78	trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
		79	local_irq_restore(flags);
49	}	80	}
50		81
51	static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,	82	static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
@@ -394,6 +425,8 @@ static int blk_trace_startstop(request_queue_t *q, int start)
394	blktrace_seq++;	425	blktrace_seq++;
395	smp_mb();	426	smp_mb();
396	bt->trace_state = Blktrace_running;	427	bt->trace_state = Blktrace_running;
		428
		429	trace_note_time(bt);
397	ret = 0;	430	ret = 0;
398	}	431	}
399	} else {	432	} else {

/* * Generic hugetlb support. * (C) William Irwin, April 2004 */ #include <linux/list.h> #include <linux/init.h> #include <linux/module.h> #include <linux/mm.h> #include <linux/seq_file.h> #include <linux/sysctl.h> #include <linux/highmem.h> #include <linux/mmu_notifier.h> #include <linux/nodemask.h> #include <linux/pagemap.h> #include <linux/mempolicy.h> #include <linux/cpuset.h> #include <linux/mutex.h> #include <linux/bootmem.h> #include <linux/sysfs.h> #include <linux/slab.h> #include <linux/rmap.h> #include <linux/swap.h> #include <linux/swapops.h> #include <asm/page.h> #include <asm/pgtable.h> #include <asm/io.h> #include <linux/hugetlb.h> #include <linux/node.h> #include "internal.h" const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; static gfp_t htlb_alloc_mask = GFP_HIGHUSER; unsigned long hugepages_treat_as_movable; static int max_hstate; unsigned int default_hstate_idx; struct hstate hstates[HUGE_MAX_HSTATE]; __initdata LIST_HEAD(huge_boot_pages); /* for command line parsing */ static struct hstate * __initdata parsed_hstate; static unsigned long __initdata default_hstate_max_huge_pages; static unsigned long __initdata default_hstate_size; #define for_each_hstate(h) \ for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++) /* * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages */ static DEFINE_SPINLOCK(hugetlb_lock); /* * Region tracking -- allows tracking of reservations and instantiated pages * across the pages in a mapping. * * The region data structures are protected by a combination of the mmap_sem * and the hugetlb_instantion_mutex. To access or modify a region the caller * must either hold the mmap_sem for write, or the mmap_sem for read and * the hugetlb_instantiation mutex: * * down_write(&mm->mmap_sem); * or * down_read(&mm->mmap_sem); * mutex_lock(&hugetlb_instantiation_mutex); */ struct file_region { struct list_head link; long from; long to; }; static long region_add(struct list_head *head, long f, long t) { struct file_region *rg, *nrg, *trg; /* Locate the region we are either in or before. */ list_for_each_entry(rg, head, link) if (f <= rg->to) break; /* Round our left edge to the current segment if it encloses us. */ if (f > rg->from) f = rg->from; /* Check for and consume any regions we now overlap with. */ nrg = rg; list_for_each_entry_safe(rg, trg, rg->link.prev, link) { if (&rg->link == head) break; if (rg->from > t) break; /* If this area reaches higher then extend our area to * include it completely. If this is not the first area * which we intend to reuse, free it. */ if (rg->to > t) t = rg->to; if (rg != nrg) { list_del(&rg->link); kfree(rg); } } nrg->from = f; nrg->to = t; return 0; } static long region_chg(struct list_head *head, long f, long t) { struct file_region *rg, *nrg; long chg = 0; /* Locate the region we are before or in. */ list_for_each_entry(rg, head, link) if (f <= rg->to) break; /* If we are below the current region then a new region is required. * Subtle, allocate a new region at the position but make it zero * size such that we can guarantee to record the reservation. */ if (&rg->link == head || t < rg->from) { nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); if (!nrg) return -ENOMEM; nrg->from = f; nrg->to = f; INIT_LIST_HEAD(&nrg->link); list_add(&nrg->link, rg->link.prev); return t - f; } /* Round our left edge to the current segment if it encloses us. */ if (f > rg->from) f = rg->from; chg = t - f; /* Check for and consume any regions we now overlap with. */ list_for_each_entry(rg, rg->link.prev, link) { if (&rg->link == head) break; if (rg->from > t) return chg; /* We overlap with this area, if it extends further than * us then we must extend ourselves. Account for its * existing reservation. */ if (rg->to > t) { chg += rg->to - t; t = rg->to; } chg -= rg->to - rg->from; } return chg; } static long region_truncate(struct list_head *head, long end) { struct file_region *rg, *trg; long chg = 0; /* Locate the region we are either in or before. */ list_for_each_entry(rg, head, link) if (end <= rg->to) break; if (&rg->link == head) return 0; /* If we are in the middle of a region then adjust it. */ if (end > rg->from) { chg = rg->to - end; rg->to = end; rg = list_entry(rg->link.next, typeof(*rg), link); } /* Drop any remaining regions. */ list_for_each_entry_safe(rg, trg, rg->link.prev, link) { if (&rg->link == head) break; chg += rg->to - rg->from; list_del(&rg->link); kfree(rg); } return chg; } static long region_count(struct list_head *head, long f, long t) { struct file_region *rg; long chg = 0; /* Locate each segment we overlap with, and count that overlap. */ list_for_each_entry(rg, head, link) { int seg_from; int seg_to; if (rg->to <= f) continue; if (rg->from >= t) break; seg_from = max(rg->from, f); seg_to = min(rg->to, t); chg += seg_to - seg_from; } return chg; } /* * Convert the address within this vma to the page offset within * the mapping, in pagecache page units; huge pages here. */ static pgoff_t vma_hugecache_offset(struct hstate *h, struct vm_area_struct *vma, unsigned long address) { return ((address - vma->vm_start) >> huge_page_shift(h)) + (vma->vm_pgoff >> huge_page_order(h)); } pgoff_t linear_hugepage_index(struct vm_area_struct *vma, unsigned long address) { return vma_hugecache_offset(hstate_vma(vma), vma, address); } /* * Return the size of the pages allocated when backing a VMA. In the majority * cases this will be same size as used by the page table entries. */ unsigned long vma_kernel_pagesize(struct vm_area_struct *vma) { struct hstate *hstate; if (!is_vm_hugetlb_page(vma)) return PAGE_SIZE; hstate = hstate_vma(vma); return 1UL << (hstate->order + PAGE_SHIFT); } EXPORT_SYMBOL_GPL(vma_kernel_pagesize); /* * Return the page size being used by the MMU to back a VMA. In the majority * of cases, the page size used by the kernel matches the MMU size. On * architectures where it differs, an architecture-specific version of this * function is required. */ #ifndef vma_mmu_pagesize unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) { return vma_kernel_pagesize(vma); } #endif /* * Flags for MAP_PRIVATE reservations. These are stored in the bottom * bits of the reservation map pointer, which are always clear due to * alignment. */ #define HPAGE_RESV_OWNER (1UL << 0) #define HPAGE_RESV_UNMAPPED (1UL << 1) #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED) /* * These helpers are used to track how many pages are reserved for * faults in a MAP_PRIVATE mapping. Only the process that called mmap() * is guaranteed to have their future faults succeed. * * With the exception of reset_vma_resv_huge_pages() which is called at fork(), * the reserve counters are updated with the hugetlb_lock held. It is safe * to reset the VMA at fork() time as it is not in use yet and there is no * chance of the global counters getting corrupted as a result of the values. * * The private mapping reservation is represented in a subtly different * manner to a shared mapping. A shared mapping has a region map associated * with the underlying file, this region map represents the backing file * pages which have ever had a reservation assigned which this persists even * after the page is instantiated. A private mapping has a region map * associated with the original mmap which is attached to all VMAs which * reference it, this region map represents those offsets which have consumed * reservation ie. where pages have been instantiated. */ static unsigned long get_vma_private_data(struct vm_area_struct *vma) { return (unsigned long)vma->vm_private_data; } static void set_vma_private_data(struct vm_area_struct *vma, unsigned long value) { vma->vm_private_data = (void *)value; } struct resv_map { struct kref refs; struct list_head regions; }; static struct resv_map *resv_map_alloc(void) { struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL); if (!resv_map) return NULL; kref_init(&resv_map->refs); INIT_LIST_HEAD(&resv_map->regions); return resv_map; } static void resv_map_release(struct kref *ref) { struct resv_map *resv_map = container_of(ref, struct resv_map, refs); /* Clear out any active regions before we release the map. */ region_truncate(&resv_map->regions, 0); kfree(resv_map); } static struct resv_map *vma_resv_map(struct vm_area_struct *vma) { VM_BUG_ON(!is_vm_hugetlb_page(vma)); if (!(vma->vm_flags & VM_MAYSHARE)) return (struct resv_map *)(get_vma_private_data(vma) & ~HPAGE_RESV_MASK); return NULL; } static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map) { VM_BUG_ON(!is_vm_hugetlb_page(vma)); VM_BUG_ON(vma->vm_flags & VM_MAYSHARE); set_vma_private_data(vma, (get_vma_private_data(vma) & HPAGE_RESV_MASK) | (unsigned long)map); } static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags) { VM_BUG_ON(!is_vm_hugetlb_page(vma)); VM_BUG_ON(vma->vm_flags & VM_MAYSHARE); set_vma_private_data(vma, get_vma_private_data(vma) | flags); } static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) { VM_BUG_ON(!is_vm_hugetlb_page(vma)); return (get_vma_private_data(vma) & flag) != 0; } /* Decrement the reserved pages in the hugepage pool by one */ static void decrement_hugepage_resv_vma(struct hstate *h, struct vm_area_struct *vma) { if (vma->vm_flags & VM_NORESERVE) return; if (vma->vm_flags & VM_MAYSHARE) { /* Shared mappings always use reserves */ h->resv_huge_pages--; } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { /* * Only the process that called mmap() has reserves for * private mappings. */ h->resv_huge_pages--; } } /* Reset counters to 0 and clear all HPAGE_RESV_* flags */ void reset_vma_resv_huge_pages(struct vm_area_struct *vma) { VM_BUG_ON(!is_vm_hugetlb_page(vma)); if (!(vma->vm_flags & VM_MAYSHARE)) vma->vm_private_data = (void *)0; } /* Returns true if the VMA has associated reserve pages */ static int vma_has_reserves(struct vm_area_struct *vma) { if (vma->vm_flags & VM_MAYSHARE) return 1; if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) return 1; return 0; } static void copy_gigantic_page(struct page *dst, struct page *src) { int i; struct hstate *h = page_hstate(src); struct page *dst_base = dst; struct page *src_base = src; for (i = 0; i < pages_per_huge_page(h); ) { cond_resched(); copy_highpage(dst, src); i++; dst = mem_map_next(dst, dst_base, i); src = mem_map_next(src, src_base, i); } } void copy_huge_page(struct page *dst, struct page *src) { int i; struct hstate *h = page_hstate(src); if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) { copy_gigantic_page(dst, src); return; } might_sleep(); for (i = 0; i < pages_per_huge_page(h); i++) { cond_resched(); copy_highpage(dst + i, src + i); } } static void enqueue_huge_page(struct hstate *h, struct page *page) { int nid = page_to_nid(page); list_add(&page->lru, &h->hugepage_freelists[nid]); h->free_huge_pages++; h->free_huge_pages_node[nid]++; } static struct page *dequeue_huge_page_node(struct hstate *h, int nid) { struct page *page; if (list_empty(&h->hugepage_freelists[nid])) return NULL; page = list_entry(h->hugepage_freelists[nid].next, struct page, lru); list_del(&page->lru); set_page_refcounted(page); h->free_huge_pages--; h->free_huge_pages_node[nid]--; return page; } static struct page *dequeue_huge_page_vma(struct hstate *h, struct vm_area_struct *vma, unsigned long address, int avoid_reserve) { struct page *page = NULL; struct mempolicy *mpol; nodemask_t *nodemask; struct zonelist *zonelist; struct zone *zone; struct zoneref *z; get_mems_allowed(); zonelist = huge_zonelist(vma, address, htlb_alloc_mask, &mpol, &nodemask); /* * A child process with MAP_PRIVATE mappings created by their parent * have no page reserves. This check ensures that reservations are * not "stolen". The child may still get SIGKILLed */ if (!vma_has_reserves(vma) && h->free_huge_pages - h->resv_huge_pages == 0) goto err; /* If reserves cannot be used, ensure enough pages are in the pool */ if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0) goto err; for_each_zone_zonelist_nodemask(zone, z, zonelist, MAX_NR_ZONES - 1, nodemask) { if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask)) { page = dequeue_huge_page_node(h, zone_to_nid(zone)); if (page) { if (!avoid_reserve) decrement_hugepage_resv_vma(h, vma); break; } } } err: mpol_cond_put(mpol); put_mems_allowed(); return page; } static void update_and_free_page(struct hstate *h, struct page *page) { int i; VM_BUG_ON(h->order >= MAX_ORDER); h->nr_huge_pages--; h->nr_huge_pages_node[page_to_nid(page)]--; for (i = 0; i < pages_per_huge_page(h); i++) { page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced | 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved | 1 << PG_private | 1<< PG_writeback); } set_compound_page_dtor(page, NULL); set_page_refcounted(page); arch_release_hugepage(page); __free_pages(page, huge_page_order(h)); } struct hstate *size_to_hstate(unsigned long size) { struct hstate *h; for_each_hstate(h) { if (huge_page_size(h) == size) return h; } return NULL; } static void free_huge_page(struct page *page) { /* * Can't pass hstate in here because it is called from the * compound page destructor. */ struct hstate *h = page_hstate(page); int nid = page_to_nid(page); struct address_space *mapping; mapping = (struct address_space *) page_private(page); set_page_private(page, 0); page->mapping = NULL; BUG_ON(page_count(page)); BUG_ON(page_mapcount(page)); INIT_LIST_HEAD(&page->lru); spin_lock(&hugetlb_lock); if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) { update_and_free_page(h, page); h->surplus_huge_pages--; h->surplus_huge_pages_node[nid]--; } else { enqueue_huge_page(h, page); } spin_unlock(&hugetlb_lock); if (mapping) hugetlb_put_quota(mapping, 1); } static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) { set_compound_page_dtor(page, free_huge_page); spin_lock(&hugetlb_lock); h->nr_huge_pages++; h->nr_huge_pages_node[nid]++; spin_unlock(&hugetlb_lock); put_page(page); /* free it into the hugepage allocator */ } static void prep_compound_gigantic_page(struct page *page, unsigned long order) { int i; int nr_pages = 1 << order; struct page *p = page + 1; /* we rely on prep_new_huge_page to set the destructor */ set_compound_order(page, order); __SetPageHead(page); for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { __SetPageTail(p); p->first_page = page; } } int PageHuge(struct page *page) { compound_page_dtor *dtor; if (!PageCompound(page)) return 0; page = compound_head(page); dtor = get_compound_page_dtor(page); return dtor == free_huge_page; } EXPORT_SYMBOL_GPL(PageHuge); static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid) { struct page *page; if (h->order >= MAX_ORDER) return NULL; page = alloc_pages_exact_node(nid, htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE| __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h)); if (page) { if (arch_prepare_hugepage(page)) { __free_pages(page, huge_page_order(h)); return NULL; } prep_new_huge_page(h, page, nid); } return page; } /* * common helper functions for hstate_next_node_to_{alloc|free}. * We may have allocated or freed a huge page based on a different * nodes_allowed previously, so h->next_node_to_{alloc|free} might * be outside of *nodes_allowed. Ensure that we use an allowed * node for alloc or free. */ static int next_node_allowed(int nid, nodemask_t *nodes_allowed) { nid = next_node(nid, *nodes_allowed); if (nid == MAX_NUMNODES) nid = first_node(*nodes_allowed); VM_BUG_ON(nid >= MAX_NUMNODES); return nid; } static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed) { if (!node_isset(nid, *nodes_allowed)) nid = next_node_allowed(nid, nodes_allowed); return nid; } /* * returns the previously saved node ["this node"] from which to * allocate a persistent huge page for the pool and advance the * next node from which to allocate, handling wrap at end of node * mask. */ static int hstate_next_node_to_alloc(struct hstate *h, nodemask_t *nodes_allowed) { int nid; VM_BUG_ON(!nodes_allowed); nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed); h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed); return nid; } static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed) { struct page *page; int start_nid; int next_nid; int ret = 0; start_nid = hstate_next_node_to_alloc(h, nodes_allowed); next_nid = start_nid; do { page = alloc_fresh_huge_page_node(h, next_nid); if (page) { ret = 1; break; } next_nid = hstate_next_node_to_alloc(h, nodes_allowed); } while (next_nid != start_nid); if (ret) count_vm_event(HTLB_BUDDY_PGALLOC); else count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); return ret; } /* * helper for free_pool_huge_page() - return the previously saved * node ["this node"] from which to free a huge page. Advance the * next node id whether or not we find a free huge page to free so * that the next attempt to free addresses the next node. */ static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed) { int nid; VM_BUG_ON(!nodes_allowed); nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed); h->next_nid_to_free = next_node_allowed(nid, nodes_allowed); return nid; } /* * Free huge page from pool from next node to free. * Attempt to keep persistent huge pages more or less * balanced over allowed nodes. * Called with hugetlb_lock locked. */ static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, bool acct_surplus) { int start_nid; int next_nid; int ret = 0; start_nid = hstate_next_node_to_free(h, nodes_allowed); next_nid = start_nid; do { /* * If we're returning unused surplus pages, only examine * nodes with surplus pages. */ if ((!acct_surplus || h->surplus_huge_pages_node[next_nid]) && !list_empty(&h->hugepage_freelists[next_nid])) { struct page *page = list_entry(h->hugepage_freelists[next_nid].next, struct page, lru); list_del(&page->lru); h->free_huge_pages--; h->free_huge_pages_node[next_nid]--; if (acct_surplus) { h->surplus_huge_pages--; h->surplus_huge_pages_node[next_nid]--; } update_and_free_page(h, page); ret = 1; break; } next_nid = hstate_next_node_to_free(h, nodes_allowed); } while (next_nid != start_nid); return ret; } static struct page *alloc_buddy_huge_page(struct hstate *h, int nid) { struct page *page; unsigned int r_nid; if (h->order >= MAX_ORDER) return NULL; /* * Assume we will successfully allocate the surplus page to * prevent racing processes from causing the surplus to exceed * overcommit * * This however introduces a different race, where a process B * tries to grow the static hugepage pool while alloc_pages() is * called by process A. B will only examine the per-node * counters in determining if surplus huge pages can be * converted to normal huge pages in adjust_pool_surplus(). A * won't be able to increment the per-node counter, until the * lock is dropped by B, but B doesn't drop hugetlb_lock until * no more huge pages can be converted from surplus to normal * state (and doesn't try to convert again). Thus, we have a * case where a surplus huge page exists, the pool is grown, and * the surplus huge page still exists after, even though it * should just have been converted to a normal huge page. This * does not leak memory, though, as the hugepage will be freed * once it is out of use. It also does not allow the counters to * go out of whack in adjust_pool_surplus() as we don't modify * the node values until we've gotten the hugepage and only the * per-node value is checked there. */ spin_lock(&hugetlb_lock); if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { spin_unlock(&hugetlb_lock); return NULL; } else { h->nr_huge_pages++; h->surplus_huge_pages++; } spin_unlock(&hugetlb_lock); if (nid == NUMA_NO_NODE) page = alloc_pages(htlb_alloc_mask|__GFP_COMP| __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h)); else page = alloc_pages_exact_node(nid, htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE| __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h)); if (page && arch_prepare_hugepage(page)) { __free_pages(page, huge_page_order(h)); return NULL; } spin_lock(&hugetlb_lock); if (page) { r_nid = page_to_nid(page); set_compound_page_dtor(page, free_huge_page); /* * We incremented the global counters already */ h->nr_huge_pages_node[r_nid]++; h->surplus_huge_pages_node[r_nid]++; __count_vm_event(HTLB_BUDDY_PGALLOC); } else { h->nr_huge_pages--; h->surplus_huge_pages--; __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); } spin_unlock(&hugetlb_lock); return page; } /* * This allocation function is useful in the context where vma is irrelevant. * E.g. soft-offlining uses this function because it only cares physical * address of error page. */ struct page *alloc_huge_page_node(struct hstate *h, int nid) { struct page *page; spin_lock(&hugetlb_lock); page = dequeue_huge_page_node(h, nid); spin_unlock(&hugetlb_lock); if (!page) page = alloc_buddy_huge_page(h, nid); return page; } /* * Increase the hugetlb pool such that it can accommodate a reservation * of size 'delta'. */ static int gather_surplus_pages(struct hstate *h, int delta) { struct list_head surplus_list; struct page *page, *tmp; int ret, i; int needed, allocated; needed = (h->resv_huge_pages + delta) - h->free_huge_pages; if (needed <= 0) { h->resv_huge_pages += delta; return 0; } allocated = 0; INIT_LIST_HEAD(&surplus_list); ret = -ENOMEM; retry: spin_unlock(&hugetlb_lock); for (i = 0; i < needed; i++) { page = alloc_buddy_huge_page(h, NUMA_NO_NODE); if (!page) /* * We were not able to allocate enough pages to * satisfy the entire reservation so we free what * we've allocated so far. */ goto free; list_add(&page->lru, &surplus_list); } allocated += needed; /* * After retaking hugetlb_lock, we need to recalculate 'needed' * because either resv_huge_pages or free_huge_pages may have changed. */ spin_lock(&hugetlb_lock); needed = (h->resv_huge_pages + delta) - (h->free_huge_pages + allocated); if (needed > 0) goto retry; /* * The surplus_list now contains _at_least_ the number of extra pages * needed to accommodate the reservation. Add the appropriate number * of pages to the hugetlb pool and free the extras back to the buddy * allocator. Commit the entire reservation here to prevent another * process from stealing the pages as they are added to the pool but * before they are reserved. */ needed += allocated; h->resv_huge_pages += delta; ret = 0; spin_unlock(&hugetlb_lock); /* Free the needed pages to the hugetlb pool */ list_for_each_entry_safe(page, tmp, &surplus_list, lru) { if ((--needed) < 0) break; list_del(&page->lru); /* * This page is now managed by the hugetlb allocator and has * no users -- drop the buddy allocator's reference. */ put_page_testzero(page); VM_BUG_ON(page_count(page)); enqueue_huge_page(h, page); } /* Free unnecessary surplus pages to the buddy allocator */ free: if (!list_empty(&surplus_list)) { list_for_each_entry_safe(page, tmp, &surplus_list, lru) { list_del(&page->lru); put_page(page); } } spin_lock(&hugetlb_lock); return ret; } /* * When releasing a hugetlb pool reservation, any surplus pages that were * allocated to satisfy the reservation must be explicitly freed if they were * never used. * Called with hugetlb_lock held. */ static void return_unused_surplus_pages(struct hstate *h, unsigned long unused_resv_pages) { unsigned long nr_pages; /* Uncommit the reservation */ h->resv_huge_pages -= unused_resv_pages; /* Cannot return gigantic pages currently */ if (h->order >= MAX_ORDER) return; nr_pages = min(unused_resv_pages, h->surplus_huge_pages); /* * We want to release as many surplus pages as possible, spread * evenly across all nodes with memory. Iterate across these nodes * until we can no longer free unreserved surplus pages. This occurs * when the nodes with surplus pages have no free pages. * free_pool_huge_page() will balance the the freed pages across the * on-line nodes with memory and will handle the hstate accounting. */ while (nr_pages--) { if (!free_pool_huge_page(h, &node_states[N_HIGH_MEMORY], 1)) break; } } /* * Determine if the huge page at addr within the vma has an associated * reservation. Where it does not we will need to logically increase * reservation and actually increase quota before an allocation can occur. * Where any new reservation would be required the reservation change is * prepared, but not committed. Once the page has been quota'd allocated * an instantiated the change should be committed via vma_commit_reservation. * No action is required on failure. */ static long vma_needs_reservation(struct hstate *h, struct vm_area_struct *vma, unsigned long addr) { struct address_space *mapping = vma->vm_file->f_mapping; struct inode *inode = mapping->host; if (vma->vm_flags & VM_MAYSHARE) { pgoff_t idx = vma_hugecache_offset(h, vma, addr); return region_chg(&inode->i_mapping->private_list, idx, idx + 1); } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { return 1; } else { long err; pgoff_t idx = vma_hugecache_offset(h, vma, addr); struct resv_map *reservations = vma_resv_map(vma); err = region_chg(&reservations->regions, idx, idx + 1); if (err < 0) return err; return 0; } } static void vma_commit_reservation(struct hstate *h, struct vm_area_struct *vma, unsigned long addr) { struct address_space *mapping = vma->vm_file->f_mapping; struct inode *inode = mapping->host; if (vma->vm_flags & VM_MAYSHARE) { pgoff_t idx = vma_hugecache_offset(h, vma, addr); region_add(&inode->i_mapping->private_list, idx, idx + 1); } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { pgoff_t idx = vma_hugecache_offset(h, vma, addr); struct resv_map *reservations = vma_resv_map(vma); /* Mark this page used in the map. */ region_add(&reservations->regions, idx, idx + 1); } } static struct page *alloc_huge_page(struct vm_area_struct *vma, unsigned long addr, int avoid_reserve) { struct hstate *h = hstate_vma(vma); struct page *page; struct address_space *mapping = vma->vm_file->f_mapping; struct inode *inode = mapping->host; long chg; /* * Processes that did not create the mapping will have no reserves and * will not have accounted against quota. Check that the quota can be * made before satisfying the allocation * MAP_NORESERVE mappings may also need pages and quota allocated * if no reserve mapping overlaps. */ chg = vma_needs_reservation(h, vma, addr); if (chg < 0) return ERR_PTR(-VM_FAULT_OOM); if (chg) if (hugetlb_get_quota(inode->i_mapping, chg)) return ERR_PTR(-VM_FAULT_SIGBUS); spin_lock(&hugetlb_lock); page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve); spin_unlock(&hugetlb_lock); if (!page) { page = alloc_buddy_huge_page(h, NUMA_NO_NODE); if (!page) { hugetlb_put_quota(inode->i_mapping, chg); return ERR_PTR(-VM_FAULT_SIGBUS); } } set_page_private(page, (unsigned long) mapping); vma_commit_reservation(h, vma, addr); return page; } int __weak alloc_bootmem_huge_page(struct hstate *h) { struct huge_bootmem_page *m; int nr_nodes = nodes_weight(node_states[N_HIGH_MEMORY]); while (nr_nodes) { void *addr; addr = __alloc_bootmem_node_nopanic( NODE_DATA(hstate_next_node_to_alloc(h, &node_states[N_HIGH_MEMORY])), huge_page_size(h), huge_page_size(h), 0); if (addr) { /* * Use the beginning of the huge page to store the * huge_bootmem_page struct (until gather_bootmem * puts them into the mem_map). */ m = addr; goto found; } nr_nodes--; } return 0; found: BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1)); /* Put them into a private list first because mem_map is not up yet */ list_add(&m->list, &huge_boot_pages); m->hstate = h; return 1; } static void prep_compound_huge_page(struct page *page, int order) { if (unlikely(order > (MAX_ORDER - 1))) prep_compound_gigantic_page(page, order); else prep_compound_page(page, order); } /* Put bootmem huge pages into the standard lists after mem_map is up */ static void __init gather_bootmem_prealloc(void) { struct huge_bootmem_page *m; list_for_each_entry(m, &huge_boot_pages, list) { struct page *page = virt_to_page(m); struct hstate *h = m->hstate; __ClearPageReserved(page); WARN_ON(page_count(page) != 1); prep_compound_huge_page(page, h->order); prep_new_huge_page(h, page, page_to_nid(page)); } } static void __init hugetlb_hstate_alloc_pages(struct hstate *h) { unsigned long i; for (i = 0; i < h->max_huge_pages; ++i) { if (h->order >= MAX_ORDER) { if (!alloc_bootmem_huge_page(h)) break; } else if (!alloc_fresh_huge_page(h, &node_states[N_HIGH_MEMORY])) break; } h->max_huge_pages = i; } static void __init hugetlb_init_hstates(void) { struct hstate *h; for_each_hstate(h) { /* oversize hugepages were init'ed in early boot */ if (h->order < MAX_ORDER) hugetlb_hstate_alloc_pages(h); } } static char * __init memfmt(char *buf, unsigned long n) { if (n >= (1UL << 30)) sprintf(buf, "%lu GB", n >> 30); else if (n >= (1UL << 20)) sprintf(buf, "%lu MB", n >> 20); else sprintf(buf, "%lu KB", n >> 10); return buf; } static void __init report_hugepages(void) { struct hstate *h; for_each_hstate(h) { char buf[32]; printk(KERN_INFO "HugeTLB registered %s page size, " "pre-allocated %ld pages\n", memfmt(buf, huge_page_size(h)), h->free_huge_pages); } } #ifdef CONFIG_HIGHMEM static void try_to_free_low(struct hstate *h, unsigned long count, nodemask_t *nodes_allowed) { int i; if (h->order >= MAX_ORDER) return; for_each_node_mask(i, *nodes_allowed) { struct page *page, *next; struct list_head *freel = &h->hugepage_freelists[i]; list_for_each_entry_safe(page, next, freel, lru) { if (count >= h->nr_huge_pages) return; if (PageHighMem(page)) continue; list_del(&page->lru); update_and_free_page(h, page); h->free_huge_pages--; h->free_huge_pages_node[page_to_nid(page)]--; } } } #else static inline void try_to_free_low(struct hstate *h, unsigned long count, nodemask_t *nodes_allowed) { } #endif /* * Increment or decrement surplus_huge_pages. Keep node-specific counters * balanced by operating on them in a round-robin fashion. * Returns 1 if an adjustment was made. */ static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed, int delta) { int start_nid, next_nid; int ret = 0; VM_BUG_ON(delta != -1 && delta != 1); if (delta < 0) start_nid = hstate_next_node_to_alloc(h, nodes_allowed); else start_nid = hstate_next_node_to_free(h, nodes_allowed); next_nid = start_nid; do { int nid = next_nid; if (delta < 0) { /* * To shrink on this node, there must be a surplus page */ if (!h->surplus_huge_pages_node[nid]) { next_nid = hstate_next_node_to_alloc(h, nodes_allowed); continue; } } if (delta > 0) { /* * Surplus cannot exceed the total number of pages */ if (h->surplus_huge_pages_node[nid] >= h->nr_huge_pages_node[nid]) { next_nid = hstate_next_node_to_free(h, nodes_allowed); continue; } } h->surplus_huge_pages += delta; h->surplus_huge_pages_node[nid] += delta; ret = 1; break; } while (next_nid != start_nid); return ret; } #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages) static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count, nodemask_t *nodes_allowed) { unsigned long min_count, ret; if (h->order >= MAX_ORDER) return h->max_huge_pages; /* * Increase the pool size * First take pages out of surplus state. Then make up the * remaining difference by allocating fresh huge pages. * * We might race with alloc_buddy_huge_page() here and be unable * to convert a surplus huge page to a normal huge page. That is * not critical, though, it just means the overall size of the * pool might be one hugepage larger than it needs to be, but * within all the constraints specified by the sysctls. */ spin_lock(&hugetlb_lock); while (h->surplus_huge_pages && count > persistent_huge_pages(h)) { if (!adjust_pool_surplus(h, nodes_allowed, -1)) break; } while (count > persistent_huge_pages(h)) { /* * If this allocation races such that we no longer need the * page, free_huge_page will handle it by freeing the page * and reducing the surplus. */ spin_unlock(&hugetlb_lock); ret = alloc_fresh_huge_page(h, nodes_allowed); spin_lock(&hugetlb_lock); if (!ret) goto out; /* Bail for signals. Probably ctrl-c from user */ if (signal_pending(current)) goto out; } /* * Decrease the pool size * First return free pages to the buddy allocator (being careful * to keep enough around to satisfy reservations). Then place * pages into surplus state as needed so the pool will shrink * to the desired size as pages become free. * * By placing pages into the surplus state independent of the * overcommit value, we are allowing the surplus pool size to * exceed overcommit. There are few sane options here. Since * alloc_buddy_huge_page() is checking the global counter, * though, we'll note that we're not allowed to exceed surplus * and won't grow the pool anywhere else. Not until one of the * sysctls are changed, or the surplus pages go out of use. */ min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages; min_count = max(count, min_count); try_to_free_low(h, min_count, nodes_allowed); while (min_count < persistent_huge_pages(h)) { if (!free_pool_huge_page(h, nodes_allowed, 0)) break; } while (count < persistent_huge_pages(h)) { if (!adjust_pool_surplus(h, nodes_allowed, 1)) break; } out: ret = persistent_huge_pages(h); spin_unlock(&hugetlb_lock); return ret; } #define HSTATE_ATTR_RO(_name) \ static struct kobj_attribute _name##_attr = __ATTR_RO(_name) #define HSTATE_ATTR(_name) \ static struct kobj_attribute _name##_attr = \ __ATTR(_name, 0644, _name##_show, _name##_store) static struct kobject *hugepages_kobj; static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp); static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp) { int i; for (i = 0; i < HUGE_MAX_HSTATE; i++) if (hstate_kobjs[i] == kobj) { if (nidp) *nidp = NUMA_NO_NODE; return &hstates[i]; } return kobj_to_node_hstate(kobj, nidp); } static ssize_t nr_hugepages_show_common(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { struct hstate *h; unsigned long nr_huge_pages; int nid; h = kobj_to_hstate(kobj, &nid); if (nid == NUMA_NO_NODE) nr_huge_pages = h->nr_huge_pages; else nr_huge_pages = h->nr_huge_pages_node[nid]; return sprintf(buf, "%lu\n", nr_huge_pages); } static ssize_t nr_hugepages_store_common(bool obey_mempolicy, struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t len) { int err; int nid; unsigned long count; struct hstate *h; NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY); err = strict_strtoul(buf, 10, &count); if (err) goto out; h = kobj_to_hstate(kobj, &nid); if (h->order >= MAX_ORDER) { err = -EINVAL; goto out; } if (nid == NUMA_NO_NODE) { /* * global hstate attribute */ if (!(obey_mempolicy && init_nodemask_of_mempolicy(nodes_allowed))) { NODEMASK_FREE(nodes_allowed); nodes_allowed = &node_states[N_HIGH_MEMORY]; } } else if (nodes_allowed) { /* * per node hstate attribute: adjust count to global, * but restrict alloc/free to the specified node. */ count += h->nr_huge_pages - h->nr_huge_pages_node[nid]; init_nodemask_of_node(nodes_allowed, nid); } else nodes_allowed = &node_states[N_HIGH_MEMORY]; h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed); if (nodes_allowed != &node_states[N_HIGH_MEMORY]) NODEMASK_FREE(nodes_allowed); return len; out: NODEMASK_FREE(nodes_allowed); return err; } static ssize_t nr_hugepages_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { return nr_hugepages_show_common(kobj, attr, buf); } static ssize_t nr_hugepages_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t len) { return nr_hugepages_store_common(false, kobj, attr, buf, len); } HSTATE_ATTR(nr_hugepages); #ifdef CONFIG_NUMA /* * hstate attribute for optionally mempolicy-based constraint on persistent * huge page alloc/free. */ static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { return nr_hugepages_show_common(kobj, attr, buf); } static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t len) { return nr_hugepages_store_common(true, kobj, attr, buf, len); } HSTATE_ATTR(nr_hugepages_mempolicy); #endif static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { struct hstate *h = kobj_to_hstate(kobj, NULL); return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages); } static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { int err; unsigned long input; struct hstate *h = kobj_to_hstate(kobj, NULL); if (h->order >= MAX_ORDER) return -EINVAL; err = strict_strtoul(buf, 10, &input); if (err) return err; spin_lock(&hugetlb_lock); h->nr_overcommit_huge_pages = input; spin_unlock(&hugetlb_lock); return count; } HSTATE_ATTR(nr_overcommit_hugepages); static ssize_t free_hugepages_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { struct hstate *h; unsigned long free_huge_pages; int nid; h = kobj_to_hstate(kobj, &nid); if (nid == NUMA_NO_NODE) free_huge_pages = h->free_huge_pages; else free_huge_pages = h->free_huge_pages_node[nid]; return sprintf(buf, "%lu\n", free_huge_pages); } HSTATE_ATTR_RO(free_hugepages); static ssize_t resv_hugepages_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { struct hstate *h = kobj_to_hstate(kobj, NULL); return sprintf(buf, "%lu\n", h->resv_huge_pages); } HSTATE_ATTR_RO(resv_hugepages); static ssize_t surplus_hugepages_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { struct hstate *h; unsigned long surplus_huge_pages; int nid; h = kobj_to_hstate(kobj, &nid); if (nid == NUMA_NO_NODE) surplus_huge_pages = h->surplus_huge_pages; else surplus_huge_pages = h->surplus_huge_pages_node[nid]; return sprintf(buf, "%lu\n", surplus_huge_pages); } HSTATE_ATTR_RO(surplus_hugepages); static struct attribute *hstate_attrs[] = { &nr_hugepages_attr.attr, &nr_overcommit_hugepages_attr.attr, &free_hugepages_attr.attr, &resv_hugepages_attr.attr, &surplus_hugepages_attr.attr, #ifdef CONFIG_NUMA &nr_hugepages_mempolicy_attr.attr, #endif NULL, }; static struct attribute_group hstate_attr_group = { .attrs = hstate_attrs, }; static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent, struct kobject **hstate_kobjs, struct attribute_group *hstate_attr_group) { int retval; int hi = h - hstates; hstate_kobjs[hi] = kobject_create_and_add(h->name, parent); if (!hstate_kobjs[hi]) return -ENOMEM; retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group); if (retval) kobject_put(hstate_kobjs[hi]); return retval; } static void __init hugetlb_sysfs_init(void) { struct hstate *h; int err; hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj); if (!hugepages_kobj) return; for_each_hstate(h) { err = hugetlb_sysfs_add_hstate(h, hugepages_kobj, hstate_kobjs, &hstate_attr_group); if (err) printk(KERN_ERR "Hugetlb: Unable to add hstate %s", h->name); } } #ifdef CONFIG_NUMA /* * node_hstate/s - associate per node hstate attributes, via their kobjects, * with node sysdevs in node_devices[] using a parallel array. The array * index of a node sysdev or _hstate == node id. * This is here to avoid any static dependency of the node sysdev driver, in * the base kernel, on the hugetlb module. */ struct node_hstate { struct kobject *hugepages_kobj; struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; }; struct node_hstate node_hstates[MAX_NUMNODES]; /* * A subset of global hstate attributes for node sysdevs */ static struct attribute *per_node_hstate_attrs[] = { &nr_hugepages_attr.attr, &free_hugepages_attr.attr, &surplus_hugepages_attr.attr, NULL, }; static struct attribute_group per_node_hstate_attr_group = { .attrs = per_node_hstate_attrs, }; /* * kobj_to_node_hstate - lookup global hstate for node sysdev hstate attr kobj. * Returns node id via non-NULL nidp. */ static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) { int nid; for (nid = 0; nid < nr_node_ids; nid++) { struct node_hstate *nhs = &node_hstates[nid]; int i; for (i = 0; i < HUGE_MAX_HSTATE; i++) if (nhs->hstate_kobjs[i] == kobj) { if (nidp) *nidp = nid; return &hstates[i]; } } BUG(); return NULL; } /* * Unregister hstate attributes from a single node sysdev. * No-op if no hstate attributes attached. */ void hugetlb_unregister_node(struct node *node) { struct hstate *h; struct node_hstate *nhs = &node_hstates[node->sysdev.id]; if (!nhs->hugepages_kobj) return; /* no hstate attributes */ for_each_hstate(h) if (nhs->hstate_kobjs[h - hstates]) { kobject_put(nhs->hstate_kobjs[h - hstates]); nhs->hstate_kobjs[h - hstates] = NULL; } kobject_put(nhs->hugepages_kobj); nhs->hugepages_kobj = NULL; } /* * hugetlb module exit: unregister hstate attributes from node sysdevs * that have them. */ static void hugetlb_unregister_all_nodes(void) { int nid; /* * disable node sysdev registrations. */ register_hugetlbfs_with_node(NULL, NULL); /* * remove hstate attributes from any nodes that have them. */ for (nid = 0; nid < nr_node_ids; nid++) hugetlb_unregister_node(&node_devices[nid]); } /* * Register hstate attributes for a single node sysdev. * No-op if attributes already registered. */ void hugetlb_register_node(struct node *node) { struct hstate *h; struct node_hstate *nhs = &node_hstates[node->sysdev.id]; int err; if (nhs->hugepages_kobj) return; /* already allocated */ nhs->hugepages_kobj = kobject_create_and_add("hugepages", &node->sysdev.kobj); if (!nhs->hugepages_kobj) return; for_each_hstate(h) { err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj, nhs->hstate_kobjs, &per_node_hstate_attr_group); if (err) { printk(KERN_ERR "Hugetlb: Unable to add hstate %s" " for node %d\n", h->name, node->sysdev.id); hugetlb_unregister_node(node); break; } } } /* * hugetlb init time: register hstate attributes for all registered node * sysdevs of nodes that have memory. All on-line nodes should have * registered their associated sysdev by this time. */ static void hugetlb_register_all_nodes(void) { int nid; for_each_node_state(nid, N_HIGH_MEMORY) { struct node *node = &node_devices[nid]; if (node->sysdev.id == nid) hugetlb_register_node(node); } /* * Let the node sysdev driver know we're here so it can * [un]register hstate attributes on node hotplug. */ register_hugetlbfs_with_node(hugetlb_register_node, hugetlb_unregister_node); } #else /* !CONFIG_NUMA */ static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) { BUG(); if (nidp) *nidp = -1; return NULL; } static void hugetlb_unregister_all_nodes(void) { } static void hugetlb_register_all_nodes(void) { } #endif static void __exit hugetlb_exit(void) { struct hstate *h; hugetlb_unregister_all_nodes(); for_each_hstate(h) { kobject_put(hstate_kobjs[h - hstates]); } kobject_put(hugepages_kobj); } module_exit(hugetlb_exit); static int __init hugetlb_init(void) { /* Some platform decide whether they support huge pages at boot * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when * there is no such support */ if (HPAGE_SHIFT == 0) return 0; if (!size_to_hstate(default_hstate_size)) { default_hstate_size = HPAGE_SIZE; if (!size_to_hstate(default_hstate_size)) hugetlb_add_hstate(HUGETLB_PAGE_ORDER); } default_hstate_idx = size_to_hstate(default_hstate_size) - hstates; if (default_hstate_max_huge_pages) default_hstate.max_huge_pages = default_hstate_max_huge_pages; hugetlb_init_hstates(); gather_bootmem_prealloc(); report_hugepages(); hugetlb_sysfs_init(); hugetlb_register_all_nodes(); return 0; } module_init(hugetlb_init); /* Should be called on processing a hugepagesz=... option */ void __init hugetlb_add_hstate(unsigned order) { struct hstate *h; unsigned long i; if (size_to_hstate(PAGE_SIZE << order)) { printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n"); return; } BUG_ON(max_hstate >= HUGE_MAX_HSTATE); BUG_ON(order == 0); h = &hstates[max_hstate++]; h->order = order; h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1); h->nr_huge_pages = 0; h->free_huge_pages = 0; for (i = 0; i < MAX_NUMNODES; ++i) INIT_LIST_HEAD(&h->hugepage_freelists[i]); h->next_nid_to_alloc = first_node(node_states[N_HIGH_MEMORY]); h->next_nid_to_free = first_node(node_states[N_HIGH_MEMORY]); snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", huge_page_size(h)/1024); parsed_hstate = h; } static int __init hugetlb_nrpages_setup(char *s) { unsigned long *mhp; static unsigned long *last_mhp; /* * !max_hstate means we haven't parsed a hugepagesz= parameter yet, * so this hugepages= parameter goes to the "default hstate". */ if (!max_hstate) mhp = &default_hstate_max_huge_pages; else mhp = &parsed_hstate->max_huge_pages; if (mhp == last_mhp) { printk(KERN_WARNING "hugepages= specified twice without " "interleaving hugepagesz=, ignoring\n"); return 1; } if (sscanf(s, "%lu", mhp) <= 0) *mhp = 0; /* * Global state is always initialized later in hugetlb_init. * But we need to allocate >= MAX_ORDER hstates here early to still * use the bootmem allocator. */ if (max_hstate && parsed_hstate->order >= MAX_ORDER) hugetlb_hstate_alloc_pages(parsed_hstate); last_mhp = mhp; return 1; } __setup("hugepages=", hugetlb_nrpages_setup); static int __init hugetlb_default_setup(char *s) { default_hstate_size = memparse(s, &s); return 1; } __setup("default_hugepagesz=", hugetlb_default_setup); static unsigned int cpuset_mems_nr(unsigned int *array) { int node; unsigned int nr = 0; for_each_node_mask(node, cpuset_current_mems_allowed) nr += array[node]; return nr; } #ifdef CONFIG_SYSCTL static int hugetlb_sysctl_handler_common(bool obey_mempolicy, struct ctl_table *table, int write, void __user *buffer, size_t *length, loff_t *ppos) { struct hstate *h = &default_hstate; unsigned long tmp; int ret; tmp = h->max_huge_pages; if (write && h->order >= MAX_ORDER) return -EINVAL; table->data = &tmp; table->maxlen = sizeof(unsigned long); ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); if (ret) goto out; if (write) { NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY); if (!(obey_mempolicy && init_nodemask_of_mempolicy(nodes_allowed))) { NODEMASK_FREE(nodes_allowed); nodes_allowed = &node_states[N_HIGH_MEMORY]; } h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed); if (nodes_allowed != &node_states[N_HIGH_MEMORY]) NODEMASK_FREE(nodes_allowed); } out: return ret; } int hugetlb_sysctl_handler(struct ctl_table *table, int write, void __user *buffer, size_t *length, loff_t *ppos) { return hugetlb_sysctl_handler_common(false, table, write, buffer, length, ppos); } #ifdef CONFIG_NUMA int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write, void __user *buffer, size_t *length, loff_t *ppos) { return hugetlb_sysctl_handler_common(true, table, write, buffer, length, ppos); } #endif /* CONFIG_NUMA */ int hugetlb_treat_movable_handler(struct ctl_table *table, int write, void __user *buffer, size_t *length, loff_t *ppos) { proc_dointvec(table, write, buffer, length, ppos); if (hugepages_treat_as_movable) htlb_alloc_mask = GFP_HIGHUSER_MOVABLE; else htlb_alloc_mask = GFP_HIGHUSER; return 0; } int hugetlb_overcommit_handler(struct ctl_table *table, int write, void __user *buffer, size_t *length, loff_t *ppos) { struct hstate *h = &default_hstate; unsigned long tmp; int ret; tmp = h->nr_overcommit_huge_pages; if (write && h->order >= MAX_ORDER) return -EINVAL; table->data = &tmp; table->maxlen = sizeof(unsigned long); ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); if (ret) goto out; if (write) { spin_lock(&hugetlb_lock); h->nr_overcommit_huge_pages = tmp; spin_unlock(&hugetlb_lock); } out: return ret; } #endif /* CONFIG_SYSCTL */ void hugetlb_report_meminfo(struct seq_file *m) { struct hstate *h = &default_hstate; seq_printf(m, "HugePages_Total: %5lu\n" "HugePages_Free: %5lu\n" "HugePages_Rsvd: %5lu\n" "HugePages_Surp: %5lu\n" "Hugepagesize: %8lu kB\n", h->nr_huge_pages, h->free_huge_pages, h->resv_huge_pages, h->surplus_huge_pages, 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); } int hugetlb_report_node_meminfo(int nid, char *buf) { struct hstate *h = &default_hstate; return sprintf(buf, "Node %d HugePages_Total: %5u\n" "Node %d HugePages_Free: %5u\n" "Node %d HugePages_Surp: %5u\n", nid, h->nr_huge_pages_node[nid], nid, h->free_huge_pages_node[nid], nid, h->surplus_huge_pages_node[nid]); } /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ unsigned long hugetlb_total_pages(void) { struct hstate *h = &default_hstate; return h->nr_huge_pages * pages_per_huge_page(h); } static int hugetlb_acct_memory(struct hstate *h, long delta) { int ret = -ENOMEM; spin_lock(&hugetlb_lock); /* * When cpuset is configured, it breaks the strict hugetlb page * reservation as the accounting is done on a global variable. Such * reservation is completely rubbish in the presence of cpuset because * the reservation is not checked against page availability for the * current cpuset. Application can still potentially OOM'ed by kernel * with lack of free htlb page in cpuset that the task is in. * Attempt to enforce strict accounting with cpuset is almost * impossible (or too ugly) because cpuset is too fluid that * task or memory node can be dynamically moved between cpusets. * * The change of semantics for shared hugetlb mapping with cpuset is * undesirable. However, in order to preserve some of the semantics, * we fall back to check against current free page availability as * a best attempt and hopefully to minimize the impact of changing * semantics that cpuset has. */ if (delta > 0) { if (gather_surplus_pages(h, delta) < 0) goto out; if (delta > cpuset_mems_nr(h->free_huge_pages_node)) { return_unused_surplus_pages(h, delta); goto out; } } ret = 0; if (delta < 0) return_unused_surplus_pages(h, (unsigned long) -delta); out: spin_unlock(&hugetlb_lock); return ret; } static void hugetlb_vm_op_open(struct vm_area_struct *vma) { struct resv_map *reservations = vma_resv_map(vma); /* * This new VMA should share its siblings reservation map if present. * The VMA will only ever have a valid reservation map pointer where * it is being copied for another still existing VMA. As that VMA * has a reference to the reservation map it cannot disappear until * after this open call completes. It is therefore safe to take a * new reference here without additional locking. */ if (reservations) kref_get(&reservations->refs); } static void hugetlb_vm_op_close(struct vm_area_struct *vma) { struct hstate *h = hstate_vma(vma); struct resv_map *reservations = vma_resv_map(vma); unsigned long reserve; unsigned long start; unsigned long end; if (reservations) { start = vma_hugecache_offset(h, vma, vma->vm_start); end = vma_hugecache_offset(h, vma, vma->vm_end); reserve = (end - start) - region_count(&reservations->regions, start, end); kref_put(&reservations->refs, resv_map_release); if (reserve) { hugetlb_acct_memory(h, -reserve); hugetlb_put_quota(vma->vm_file->f_mapping, reserve); } } } /* * We cannot handle pagefaults against hugetlb pages at all. They cause * handle_mm_fault() to try to instantiate regular-sized pages in the * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get * this far. */ static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) { BUG(); return 0; } const struct vm_operations_struct hugetlb_vm_ops = { .fault = hugetlb_vm_op_fault, .open = hugetlb_vm_op_open, .close = hugetlb_vm_op_close, }; static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, int writable) { pte_t entry; if (writable) { entry = pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); } else { entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot)); } entry = pte_mkyoung(entry); entry = pte_mkhuge(entry); return entry; } static void set_huge_ptep_writable(struct vm_area_struct *vma, unsigned long address, pte_t *ptep) { pte_t entry; entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep))); if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) { update_mmu_cache(vma, address, ptep); } } int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, struct vm_area_struct *vma) { pte_t *src_pte, *dst_pte, entry; struct page *ptepage; unsigned long addr; int cow; struct hstate *h = hstate_vma(vma); unsigned long sz = huge_page_size(h); cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { src_pte = huge_pte_offset(src, addr); if (!src_pte) continue; dst_pte = huge_pte_alloc(dst, addr, sz); if (!dst_pte) goto nomem; /* If the pagetables are shared don't copy or take references */ if (dst_pte == src_pte) continue; spin_lock(&dst->page_table_lock); spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING); if (!huge_pte_none(huge_ptep_get(src_pte))) { if (cow) huge_ptep_set_wrprotect(src, addr, src_pte); entry = huge_ptep_get(src_pte); ptepage = pte_page(entry); get_page(ptepage); page_dup_rmap(ptepage); set_huge_pte_at(dst, addr, dst_pte, entry); } spin_unlock(&src->page_table_lock); spin_unlock(&dst->page_table_lock); } return 0; nomem: return -ENOMEM; } static int is_hugetlb_entry_migration(pte_t pte) { swp_entry_t swp; if (huge_pte_none(pte) || pte_present(pte)) return 0; swp = pte_to_swp_entry(pte); if (non_swap_entry(swp) && is_migration_entry(swp)) { return 1; } else return 0; } static int is_hugetlb_entry_hwpoisoned(pte_t pte) { swp_entry_t swp; if (huge_pte_none(pte) || pte_present(pte)) return 0; swp = pte_to_swp_entry(pte); if (non_swap_entry(swp) && is_hwpoison_entry(swp)) { return 1; } else return 0; } void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, unsigned long end, struct page *ref_page) { struct mm_struct *mm = vma->vm_mm; unsigned long address; pte_t *ptep; pte_t pte; struct page *page; struct page *tmp; struct hstate *h = hstate_vma(vma); unsigned long sz = huge_page_size(h); /* * A page gathering list, protected by per file i_mmap_mutex. The * lock is used to avoid list corruption from multiple unmapping * of the same page since we are using page->lru. */ LIST_HEAD(page_list); WARN_ON(!is_vm_hugetlb_page(vma)); BUG_ON(start & ~huge_page_mask(h)); BUG_ON(end & ~huge_page_mask(h)); mmu_notifier_invalidate_range_start(mm, start, end); spin_lock(&mm->page_table_lock); for (address = start; address < end; address += sz) { ptep = huge_pte_offset(mm, address); if (!ptep) continue; if (huge_pmd_unshare(mm, &address, ptep)) continue; /* * If a reference page is supplied, it is because a specific * page is being unmapped, not a range. Ensure the page we * are about to unmap is the actual page of interest. */ if (ref_page) { pte = huge_ptep_get(ptep); if (huge_pte_none(pte)) continue; page = pte_page(pte); if (page != ref_page) continue; /* * Mark the VMA as having unmapped its page so that * future faults in this VMA will fail rather than * looking like data was lost */ set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); } pte = huge_ptep_get_and_clear(mm, address, ptep); if (huge_pte_none(pte)) continue; /* * HWPoisoned hugepage is already unmapped and dropped reference */ if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) continue; page = pte_page(pte); if (pte_dirty(pte)) set_page_dirty(page); list_add(&page->lru, &page_list); } spin_unlock(&mm->page_table_lock); flush_tlb_range(vma, start, end); mmu_notifier_invalidate_range_end(mm, start, end); list_for_each_entry_safe(page, tmp, &page_list, lru) { page_remove_rmap(page); list_del(&page->lru); put_page(page); } } void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, unsigned long end, struct page *ref_page) { mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex); __unmap_hugepage_range(vma, start, end, ref_page); mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex); } /* * This is called when the original mapper is failing to COW a MAP_PRIVATE * mappping it owns the reserve page for. The intention is to unmap the page * from other VMAs and let the children be SIGKILLed if they are faulting the * same region. */ static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, struct page *page, unsigned long address) { struct hstate *h = hstate_vma(vma); struct vm_area_struct *iter_vma; struct address_space *mapping; struct prio_tree_iter iter; pgoff_t pgoff; /* * vm_pgoff is in PAGE_SIZE units, hence the different calculation * from page cache lookup which is in HPAGE_SIZE units. */ address = address & huge_page_mask(h); pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + (vma->vm_pgoff >> PAGE_SHIFT); mapping = (struct address_space *)page_private(page); /* * Take the mapping lock for the duration of the table walk. As * this mapping should be shared between all the VMAs, * __unmap_hugepage_range() is called as the lock is already held */ mutex_lock(&mapping->i_mmap_mutex); vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) { /* Do not unmap the current VMA */ if (iter_vma == vma) continue; /* * Unmap the page from other VMAs without their own reserves. * They get marked to be SIGKILLed if they fault in these * areas. This is because a future no-page fault on this VMA * could insert a zeroed page instead of the data existing * from the time of fork. This would look like data corruption */ if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) __unmap_hugepage_range(iter_vma, address, address + huge_page_size(h), page); } mutex_unlock(&mapping->i_mmap_mutex); return 1; } /* * Hugetlb_cow() should be called with page lock of the original hugepage held. */ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, pte_t *ptep, pte_t pte, struct page *pagecache_page) { struct hstate *h = hstate_vma(vma); struct page *old_page, *new_page; int avoidcopy; int outside_reserve = 0; old_page = pte_page(pte); retry_avoidcopy: /* If no-one else is actually using this page, avoid the copy * and just make the page writable */ avoidcopy = (page_mapcount(old_page) == 1); if (avoidcopy) { if (PageAnon(old_page)) page_move_anon_rmap(old_page, vma, address); set_huge_ptep_writable(vma, address, ptep); return 0; } /* * If the process that created a MAP_PRIVATE mapping is about to * perform a COW due to a shared page count, attempt to satisfy * the allocation without using the existing reserves. The pagecache * page is used to determine if the reserve at this address was * consumed or not. If reserves were used, a partial faulted mapping * at the time of fork() could consume its reserves on COW instead * of the full address range. */ if (!(vma->vm_flags & VM_MAYSHARE) && is_vma_resv_set(vma, HPAGE_RESV_OWNER) && old_page != pagecache_page) outside_reserve = 1; page_cache_get(old_page); /* Drop page_table_lock as buddy allocator may be called */ spin_unlock(&mm->page_table_lock); new_page = alloc_huge_page(vma, address, outside_reserve); if (IS_ERR(new_page)) { page_cache_release(old_page); /* * If a process owning a MAP_PRIVATE mapping fails to COW, * it is due to references held by a child and an insufficient * huge page pool. To guarantee the original mappers * reliability, unmap the page from child processes. The child * may get SIGKILLed if it later faults. */ if (outside_reserve) { BUG_ON(huge_pte_none(pte)); if (unmap_ref_private(mm, vma, old_page, address)) { BUG_ON(page_count(old_page) != 1); BUG_ON(huge_pte_none(pte)); spin_lock(&mm->page_table_lock); goto retry_avoidcopy; } WARN_ON_ONCE(1); } /* Caller expects lock to be held */ spin_lock(&mm->page_table_lock); return -PTR_ERR(new_page); } /* * When the original hugepage is shared one, it does not have * anon_vma prepared. */ if (unlikely(anon_vma_prepare(vma))) { /* Caller expects lock to be held */ spin_lock(&mm->page_table_lock); return VM_FAULT_OOM; } copy_user_huge_page(new_page, old_page, address, vma, pages_per_huge_page(h)); __SetPageUptodate(new_page); /* * Retake the page_table_lock to check for racing updates * before the page tables are altered */ spin_lock(&mm->page_table_lock); ptep = huge_pte_offset(mm, address & huge_page_mask(h)); if (likely(pte_same(huge_ptep_get(ptep), pte))) { /* Break COW */ mmu_notifier_invalidate_range_start(mm, address & huge_page_mask(h), (address & huge_page_mask(h)) + huge_page_size(h)); huge_ptep_clear_flush(vma, address, ptep); set_huge_pte_at(mm, address, ptep, make_huge_pte(vma, new_page, 1)); page_remove_rmap(old_page); hugepage_add_new_anon_rmap(new_page, vma, address); /* Make the old page be freed below */ new_page = old_page; mmu_notifier_invalidate_range_end(mm, address & huge_page_mask(h), (address & huge_page_mask(h)) + huge_page_size(h)); } page_cache_release(new_page); page_cache_release(old_page); return 0; } /* Return the pagecache page at a given address within a VMA */ static struct page *hugetlbfs_pagecache_page(struct hstate *h, struct vm_area_struct *vma, unsigned long address) { struct address_space *mapping; pgoff_t idx; mapping = vma->vm_file->f_mapping; idx = vma_hugecache_offset(h, vma, address); return find_lock_page(mapping, idx); } /* * Return whether there is a pagecache page to back given address within VMA. * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page. */ static bool hugetlbfs_pagecache_present(struct hstate *h, struct vm_area_struct *vma, unsigned long address) { struct address_space *mapping; pgoff_t idx; struct page *page; mapping = vma->vm_file->f_mapping; idx = vma_hugecache_offset(h, vma, address); page = find_get_page(mapping, idx); if (page) put_page(page); return page != NULL; } static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, pte_t *ptep, unsigned int flags) { struct hstate *h = hstate_vma(vma); int ret = VM_FAULT_SIGBUS; pgoff_t idx; unsigned long size; struct page *page; struct address_space *mapping; pte_t new_pte; /* * Currently, we are forced to kill the process in the event the * original mapper has unmapped pages from the child due to a failed * COW. Warn that such a situation has occurred as it may not be obvious */ if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { printk(KERN_WARNING "PID %d killed due to inadequate hugepage pool\n", current->pid); return ret; }


context:
space:
mode: