1 files changed, 385 insertions, 153 deletions

diff --git a/mm/slob.c b/mm/slob.c
index 71976c5d40d3..b4899079d8b0 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -3,57 +3,159 @@
  *
  * Matt Mackall <mpm@selenic.com> 12/30/03
  *
+ * NUMA support by Paul Mundt, 2007.
+ *
  * How SLOB works:
  *
  * The core of SLOB is a traditional K&R style heap allocator, with
  * support for returning aligned objects. The granularity of this
- * allocator is 8 bytes on x86, though it's perhaps possible to reduce
- * this to 4 if it's deemed worth the effort. The slob heap is a
- * singly-linked list of pages from __get_free_page, grown on demand
- * and allocation from the heap is currently first-fit.
+ * allocator is as little as 2 bytes, however typically most architectures
+ * will require 4 bytes on 32-bit and 8 bytes on 64-bit.
+ *
+ * The slob heap is a linked list of pages from alloc_pages(), and
+ * within each page, there is a singly-linked list of free blocks (slob_t).
+ * The heap is grown on demand and allocation from the heap is currently
+ * first-fit.
  *
  * Above this is an implementation of kmalloc/kfree. Blocks returned
- * from kmalloc are 8-byte aligned and prepended with a 8-byte header.
+ * from kmalloc are prepended with a 4-byte header with the kmalloc size.
  * If kmalloc is asked for objects of PAGE_SIZE or larger, it calls
- * __get_free_pages directly so that it can return page-aligned blocks
- * and keeps a linked list of such pages and their orders. These
- * objects are detected in kfree() by their page alignment.
+ * alloc_pages() directly, allocating compound pages so the page order
+ * does not have to be separately tracked, and also stores the exact
+ * allocation size in page->private so that it can be used to accurately
+ * provide ksize(). These objects are detected in kfree() because slob_page()
+ * is false for them.
  *
  * SLAB is emulated on top of SLOB by simply calling constructors and
- * destructors for every SLAB allocation. Objects are returned with
- * the 8-byte alignment unless the SLAB_HWCACHE_ALIGN flag is
- * set, in which case the low-level allocator will fragment blocks to
- * create the proper alignment. Again, objects of page-size or greater
- * are allocated by calling __get_free_pages. As SLAB objects know
- * their size, no separate size bookkeeping is necessary and there is
- * essentially no allocation space overhead.
+ * destructors for every SLAB allocation. Objects are returned with the
+ * 4-byte alignment unless the SLAB_HWCACHE_ALIGN flag is set, in which
+ * case the low-level allocator will fragment blocks to create the proper
+ * alignment. Again, objects of page-size or greater are allocated by
+ * calling alloc_pages(). As SLAB objects know their size, no separate
+ * size bookkeeping is necessary and there is essentially no allocation
+ * space overhead, and compound pages aren't needed for multi-page
+ * allocations.
+ *
+ * NUMA support in SLOB is fairly simplistic, pushing most of the real
+ * logic down to the page allocator, and simply doing the node accounting
+ * on the upper levels. In the event that a node id is explicitly
+ * provided, alloc_pages_node() with the specified node id is used
+ * instead. The common case (or when the node id isn't explicitly provided)
+ * will default to the current node, as per numa_node_id().
+ *
+ * Node aware pages are still inserted in to the global freelist, and
+ * these are scanned for by matching against the node id encoded in the
+ * page flags. As a result, block allocations that can be satisfied from
+ * the freelist will only be done so on pages residing on the same node,
+ * in order to prevent random node placement.
  */
 
+#include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/mm.h>
 #include <linux/cache.h>
 #include <linux/init.h>
 #include <linux/module.h>
-#include <linux/timer.h>
 #include <linux/rcupdate.h>
+#include <linux/list.h>
+#include <asm/atomic.h>
+
+/*
+ * slob_block has a field 'units', which indicates size of block if +ve,
+ * or offset of next block if -ve (in SLOB_UNITs).
+ *
+ * Free blocks of size 1 unit simply contain the offset of the next block.
+ * Those with larger size contain their size in the first SLOB_UNIT of
+ * memory, and the offset of the next free block in the second SLOB_UNIT.
+ */
+#if PAGE_SIZE <= (32767 * 2)
+typedef s16 slobidx_t;
+#else
+typedef s32 slobidx_t;
+#endif
 
 struct slob_block {
-        int units;
-        struct slob_block *next;
+        slobidx_t units;
 };
 typedef struct slob_block slob_t;
 
+/*
+ * We use struct page fields to manage some slob allocation aspects,
+ * however to avoid the horrible mess in include/linux/mm_types.h, we'll
+ * just define our own struct page type variant here.
+ */
+struct slob_page {
+        union {
+                struct {
+                        unsigned long flags;    /* mandatory */
+                        atomic_t _count;        /* mandatory */
+                        slobidx_t units;        /* free units left in page */
+                        unsigned long pad[2];
+                        slob_t *free;           /* first free slob_t in page */
+                        struct list_head list;  /* linked list of free pages */
+                };
+                struct page page;
+        };
+};
+static inline void struct_slob_page_wrong_size(void)
+{ BUILD_BUG_ON(sizeof(struct slob_page) != sizeof(struct page)); }
+
+/*
+ * free_slob_page: call before a slob_page is returned to the page allocator.
+ */
+static inline void free_slob_page(struct slob_page *sp)
+{
+        reset_page_mapcount(&sp->page);
+        sp->page.mapping = NULL;
+}
+
+/*
+ * All (partially) free slob pages go on this list.
+ */
+static LIST_HEAD(free_slob_pages);
+
+/*
+ * slob_page: True for all slob pages (false for bigblock pages)
+ */
+static inline int slob_page(struct slob_page *sp)
+{
+        return test_bit(PG_active, &sp->flags);
+}
+
+static inline void set_slob_page(struct slob_page *sp)
+{
+        __set_bit(PG_active, &sp->flags);
+}
+
+static inline void clear_slob_page(struct slob_page *sp)
+{
+        __clear_bit(PG_active, &sp->flags);
+}
+
+/*
+ * slob_page_free: true for pages on free_slob_pages list.
+ */
+static inline int slob_page_free(struct slob_page *sp)
+{
+        return test_bit(PG_private, &sp->flags);
+}
+
+static inline void set_slob_page_free(struct slob_page *sp)
+{
+        list_add(&sp->list, &free_slob_pages);
+        __set_bit(PG_private, &sp->flags);
+}
+
+static inline void clear_slob_page_free(struct slob_page *sp)
+{
+        list_del(&sp->list);
+        __clear_bit(PG_private, &sp->flags);
+}
+
 #define SLOB_UNIT sizeof(slob_t)
 #define SLOB_UNITS(size) (((size) + SLOB_UNIT - 1)/SLOB_UNIT)
 #define SLOB_ALIGN L1_CACHE_BYTES
 
-struct bigblock {
-        int order;
-        void *pages;
-        struct bigblock *next;
-};
-typedef struct bigblock bigblock_t;
-
 /*
  * struct slob_rcu is inserted at the tail of allocated slob blocks, which
  * were created with a SLAB_DESTROY_BY_RCU slab. slob_rcu is used to free
@@ -64,133 +166,285 @@ struct slob_rcu {
         int size;
 };
 
-static slob_t arena = { .next = &arena, .units = 1 };
-static slob_t *slobfree = &arena;
-static bigblock_t *bigblocks;
+/*
+ * slob_lock protects all slob allocator structures.
+ */
 static DEFINE_SPINLOCK(slob_lock);
-static DEFINE_SPINLOCK(block_lock);
 
-static void slob_free(void *b, int size);
-static void slob_timer_cbk(void);
+/*
+ * Encode the given size and next info into a free slob block s.
+ */
+static void set_slob(slob_t *s, slobidx_t size, slob_t *next)
+{
+        slob_t *base = (slob_t *)((unsigned long)s & PAGE_MASK);
+        slobidx_t offset = next - base;
 
+        if (size > 1) {
+                s[0].units = size;
+                s[1].units = offset;
+        } else
+                s[0].units = -offset;
+}
 
-static void *slob_alloc(size_t size, gfp_t gfp, int align)
+/*
+ * Return the size of a slob block.
+ */
+static slobidx_t slob_units(slob_t *s)
+{
+        if (s->units > 0)
+                return s->units;
+        return 1;
+}
+
+/*
+ * Return the next free slob block pointer after this one.
+ */
+static slob_t *slob_next(slob_t *s)
+{
+        slob_t *base = (slob_t *)((unsigned long)s & PAGE_MASK);
+        slobidx_t next;
+
+        if (s[0].units < 0)
+                next = -s[0].units;
+        else
+                next = s[1].units;
+        return base+next;
+}
+
+/*
+ * Returns true if s is the last free block in its page.
+ */
+static int slob_last(slob_t *s)
+{
+        return !((unsigned long)slob_next(s) & ~PAGE_MASK);
+}
+
+static void *slob_new_page(gfp_t gfp, int order, int node)
+{
+        void *page;
+
+#ifdef CONFIG_NUMA
+        if (node != -1)
+                page = alloc_pages_node(node, gfp, order);
+        else
+#endif
+                page = alloc_pages(gfp, order);
+
+        if (!page)
+                return NULL;
+
+        return page_address(page);
+}
+
+/*
+ * Allocate a slob block within a given slob_page sp.
+ */
+static void *slob_page_alloc(struct slob_page *sp, size_t size, int align)
 {
         slob_t *prev, *cur, *aligned = 0;
         int delta = 0, units = SLOB_UNITS(size);
-        unsigned long flags;
 
-        spin_lock_irqsave(&slob_lock, flags);
-        prev = slobfree;
-        for (cur = prev->next; ; prev = cur, cur = cur->next) {
+        for (prev = NULL, cur = sp->free; ; prev = cur, cur = slob_next(cur)) {
+                slobidx_t avail = slob_units(cur);
+
                 if (align) {
                         aligned = (slob_t *)ALIGN((unsigned long)cur, align);
                         delta = aligned - cur;
                 }
-                if (cur->units >= units + delta) { /* room enough? */
+                if (avail >= units + delta) { /* room enough? */
+                        slob_t *next;
+
                         if (delta) { /* need to fragment head to align? */
-                                aligned->units = cur->units - delta;
-                                aligned->next = cur->next;
-                                cur->next = aligned;
-                                cur->units = delta;
+                                next = slob_next(cur);
+                                set_slob(aligned, avail - delta, next);
+                                set_slob(cur, delta, aligned);
                                 prev = cur;
                                 cur = aligned;
+                                avail = slob_units(cur);
                         }
 
-                        if (cur->units == units) /* exact fit? */
-                                prev->next = cur->next; /* unlink */
-                        else { /* fragment */
-                                prev->next = cur + units;
-                                prev->next->units = cur->units - units;
-                                prev->next->next = cur->next;
-                                cur->units = units;
+                        next = slob_next(cur);
+                        if (avail == units) { /* exact fit? unlink. */
+                                if (prev)
+                                        set_slob(prev, slob_units(prev), next);
+                                else
+                                        sp->free = next;
+                        } else { /* fragment */
+                                if (prev)
+                                        set_slob(prev, slob_units(prev), cur + units);
+                                else
+                                        sp->free = cur + units;
+                                set_slob(cur + units, avail - units, next);
                         }
 
-                        slobfree = prev;
-                        spin_unlock_irqrestore(&slob_lock, flags);
+                        sp->units -= units;
+                        if (!sp->units)
+                                clear_slob_page_free(sp);
                         return cur;
                 }
-                if (cur == slobfree) {
-                        spin_unlock_irqrestore(&slob_lock, flags);
-
-                        if (size == PAGE_SIZE) /* trying to shrink arena? */
-                                return 0;
+                if (slob_last(cur))
+                        return NULL;
+        }
+}
 
-                        cur = (slob_t *)__get_free_page(gfp);
-                        if (!cur)
-                                return 0;
+/*
+ * slob_alloc: entry point into the slob allocator.
+ */
+static void *slob_alloc(size_t size, gfp_t gfp, int align, int node)
+{
+        struct slob_page *sp;
+        slob_t *b = NULL;
+        unsigned long flags;
 
-                        slob_free(cur, PAGE_SIZE);
-                        spin_lock_irqsave(&slob_lock, flags);
-                        cur = slobfree;
+        spin_lock_irqsave(&slob_lock, flags);
+        /* Iterate through each partially free page, try to find room */
+        list_for_each_entry(sp, &free_slob_pages, list) {
+#ifdef CONFIG_NUMA
+                /*
+                 * If there's a node specification, search for a partial
+                 * page with a matching node id in the freelist.
+                 */
+                if (node != -1 && page_to_nid(&sp->page) != node)
+                        continue;
+#endif
+
+                if (sp->units >= SLOB_UNITS(size)) {
+                        b = slob_page_alloc(sp, size, align);
+                        if (b)
+                                break;
                 }
         }
+        spin_unlock_irqrestore(&slob_lock, flags);
+
+        /* Not enough space: must allocate a new page */
+        if (!b) {
+                b = slob_new_page(gfp, 0, node);
+                if (!b)
+                        return 0;
+                sp = (struct slob_page *)virt_to_page(b);
+                set_slob_page(sp);
+
+                spin_lock_irqsave(&slob_lock, flags);
+                sp->units = SLOB_UNITS(PAGE_SIZE);
+                sp->free = b;
+                INIT_LIST_HEAD(&sp->list);
+                set_slob(b, SLOB_UNITS(PAGE_SIZE), b + SLOB_UNITS(PAGE_SIZE));
+                set_slob_page_free(sp);
+                b = slob_page_alloc(sp, size, align);
+                BUG_ON(!b);
+                spin_unlock_irqrestore(&slob_lock, flags);
+        }
+        return b;
 }
 
+/*
+ * slob_free: entry point into the slob allocator.
+ */
 static void slob_free(void *block, int size)
 {
-        slob_t *cur, *b = (slob_t *)block;
+        struct slob_page *sp;
+        slob_t *prev, *next, *b = (slob_t *)block;
+        slobidx_t units;
         unsigned long flags;
 
         if (!block)
                 return;
+        BUG_ON(!size);
 
-        if (size)
-                b->units = SLOB_UNITS(size);
+        sp = (struct slob_page *)virt_to_page(block);
+        units = SLOB_UNITS(size);
 
-        /* Find reinsertion point */
         spin_lock_irqsave(&slob_lock, flags);
-        for (cur = slobfree; !(b > cur && b < cur->next); cur = cur->next)
-                if (cur >= cur->next && (b > cur || b < cur->next))
-                        break;
 
-        if (b + b->units == cur->next) {
-                b->units += cur->next->units;
-                b->next = cur->next->next;
-        } else
-                b->next = cur->next;
+        if (sp->units + units == SLOB_UNITS(PAGE_SIZE)) {
+                /* Go directly to page allocator. Do not pass slob allocator */
+                if (slob_page_free(sp))
+                        clear_slob_page_free(sp);
+                clear_slob_page(sp);
+                free_slob_page(sp);
+                free_page((unsigned long)b);
+                goto out;
+        }
 
-        if (cur + cur->units == b) {
-                cur->units += b->units;
-                cur->next = b->next;
-        } else
-                cur->next = b;
+        if (!slob_page_free(sp)) {
+                /* This slob page is about to become partially free. Easy! */
+                sp->units = units;
+                sp->free = b;
+                set_slob(b, units,
+                        (void *)((unsigned long)(b +
+                                        SLOB_UNITS(PAGE_SIZE)) & PAGE_MASK));
+                set_slob_page_free(sp);
+                goto out;
+        }
 
-        slobfree = cur;
+        /*
+         * Otherwise the page is already partially free, so find reinsertion
+         * point.
+         */
+        sp->units += units;
 
+        if (b < sp->free) {
+                set_slob(b, units, sp->free);
+                sp->free = b;
+        } else {
+                prev = sp->free;
+                next = slob_next(prev);
+                while (b > next) {
+                        prev = next;
+                        next = slob_next(prev);
+                }
+
+                if (!slob_last(prev) && b + units == next) {
+                        units += slob_units(next);
+                        set_slob(b, units, slob_next(next));
+                } else
+                        set_slob(b, units, next);
+
+                if (prev + slob_units(prev) == b) {
+                        units = slob_units(b) + slob_units(prev);
+                        set_slob(prev, units, slob_next(b));
+                } else
+                        set_slob(prev, slob_units(prev), b);
+        }
+out:
         spin_unlock_irqrestore(&slob_lock, flags);
 }
 
-void *__kmalloc(size_t size, gfp_t gfp)
-{
-        slob_t *m;
-        bigblock_t *bb;
-        unsigned long flags;
+/*
+ * End of slob allocator proper. Begin kmem_cache_alloc and kmalloc frontend.
+ */
 
-        if (size < PAGE_SIZE - SLOB_UNIT) {
-                m = slob_alloc(size + SLOB_UNIT, gfp, 0);
-                return m ? (void *)(m + 1) : 0;
-        }
+#ifndef ARCH_KMALLOC_MINALIGN
+#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long)
+#endif
 
-        bb = slob_alloc(sizeof(bigblock_t), gfp, 0);
-        if (!bb)
-                return 0;
+#ifndef ARCH_SLAB_MINALIGN
+#define ARCH_SLAB_MINALIGN __alignof__(unsigned long)
+#endif
 
-        bb->order = get_order(size);
-        bb->pages = (void *)__get_free_pages(gfp, bb->order);
+void *__kmalloc_node(size_t size, gfp_t gfp, int node)
+{
+        int align = max(ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN);
+
+        if (size < PAGE_SIZE - align) {
+                unsigned int *m;
+                m = slob_alloc(size + align, gfp, align, node);
+                if (m)
+                        *m = size;
+                return (void *)m + align;
+        } else {
+                void *ret;
 
-        if (bb->pages) {
-                spin_lock_irqsave(&block_lock, flags);
-                bb->next = bigblocks;
-                bigblocks = bb;
-                spin_unlock_irqrestore(&block_lock, flags);
-                return bb->pages;
+                ret = slob_new_page(gfp | __GFP_COMP, get_order(size), node);
+                if (ret) {
+                        struct page *page;
+                        page = virt_to_page(ret);
+                        page->private = size;
+                }
+                return ret;
         }
-
-        slob_free(bb, sizeof(bigblock_t));
-        return 0;
 }
-EXPORT_SYMBOL(__kmalloc);
+EXPORT_SYMBOL(__kmalloc_node);
 
 /**
  * krealloc - reallocate memory. The contents will remain unchanged.
@@ -227,52 +481,34 @@ EXPORT_SYMBOL(krealloc);
 
 void kfree(const void *block)
 {
-        bigblock_t *bb, **last = &bigblocks;
-        unsigned long flags;
+        struct slob_page *sp;
 
         if (!block)
                 return;
 
-        if (!((unsigned long)block & (PAGE_SIZE-1))) {
-                /* might be on the big block list */
-                spin_lock_irqsave(&block_lock, flags);
-                for (bb = bigblocks; bb; last = &bb->next, bb = bb->next) {
-                        if (bb->pages == block) {
-                                *last = bb->next;
-                                spin_unlock_irqrestore(&block_lock, flags);
-                                free_pages((unsigned long)block, bb->order);
-                                slob_free(bb, sizeof(bigblock_t));
-                                return;
-                        }
-                }
-                spin_unlock_irqrestore(&block_lock, flags);
-        }
-
-        slob_free((slob_t *)block - 1, 0);
-        return;
+        sp = (struct slob_page *)virt_to_page(block);
+        if (slob_page(sp)) {
+                int align = max(ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN);
+                unsigned int *m = (unsigned int *)(block - align);
+                slob_free(m, *m + align);
+        } else
+                put_page(&sp->page);
 }
-
 EXPORT_SYMBOL(kfree);
 
+/* can't use ksize for kmem_cache_alloc memory, only kmalloc */
 size_t ksize(const void *block)
 {
-        bigblock_t *bb;
-        unsigned long flags;
+        struct slob_page *sp;
 
         if (!block)
                 return 0;
 
-        if (!((unsigned long)block & (PAGE_SIZE-1))) {
-                spin_lock_irqsave(&block_lock, flags);
-                for (bb = bigblocks; bb; bb = bb->next)
-                        if (bb->pages == block) {
-                                spin_unlock_irqrestore(&slob_lock, flags);
-                                return PAGE_SIZE << bb->order;
-                        }
-                spin_unlock_irqrestore(&block_lock, flags);
-        }
-
-        return ((slob_t *)block - 1)->units * SLOB_UNIT;
+        sp = (struct slob_page *)virt_to_page(block);
+        if (slob_page(sp))
+                return ((slob_t *)block - 1)->units + SLOB_UNIT;
+        else
+                return sp->page.private;
 }
 
 struct kmem_cache {
@@ -289,7 +525,7 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size,
 {
         struct kmem_cache *c;
 
-        c = slob_alloc(sizeof(struct kmem_cache), flags, 0);
+        c = slob_alloc(sizeof(struct kmem_cache), flags, 0, -1);
 
         if (c) {
                 c->name = name;
@@ -302,6 +538,8 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size,
                 c->ctor = ctor;
                 /* ignore alignment unless it's forced */
                 c->align = (flags & SLAB_HWCACHE_ALIGN) ? SLOB_ALIGN : 0;
+                if (c->align < ARCH_SLAB_MINALIGN)
+                        c->align = ARCH_SLAB_MINALIGN;
                 if (c->align < align)
                         c->align = align;
         } else if (flags & SLAB_PANIC)
@@ -317,21 +555,21 @@ void kmem_cache_destroy(struct kmem_cache *c)
 }
 EXPORT_SYMBOL(kmem_cache_destroy);
 
-void *kmem_cache_alloc(struct kmem_cache *c, gfp_t flags)
+void *kmem_cache_alloc_node(struct kmem_cache *c, gfp_t flags, int node)
 {
         void *b;
 
         if (c->size < PAGE_SIZE)
-                b = slob_alloc(c->size, flags, c->align);
+                b = slob_alloc(c->size, flags, c->align, node);
         else
-                b = (void *)__get_free_pages(flags, get_order(c->size));
+                b = slob_new_page(flags, get_order(c->size), node);
 
         if (c->ctor)
                 c->ctor(b, c, 0);
 
         return b;
 }
-EXPORT_SYMBOL(kmem_cache_alloc);
+EXPORT_SYMBOL(kmem_cache_alloc_node);
 
 void *kmem_cache_zalloc(struct kmem_cache *c, gfp_t flags)
 {
@@ -385,9 +623,6 @@ const char *kmem_cache_name(struct kmem_cache *c)
 }
 EXPORT_SYMBOL(kmem_cache_name);
 
-static struct timer_list slob_timer = TIMER_INITIALIZER(
-        (void (*)(unsigned long))slob_timer_cbk, 0, 0);
-
 int kmem_cache_shrink(struct kmem_cache *d)
 {
         return 0;
@@ -399,17 +634,14 @@ int kmem_ptr_validate(struct kmem_cache *a, const void *b)
         return 0;
 }
 
-void __init kmem_cache_init(void)
+static unsigned int slob_ready __read_mostly;
+
+int slab_is_available(void)
 {
-        slob_timer_cbk();
+        return slob_ready;
 }
 
-static void slob_timer_cbk(void)
+void __init kmem_cache_init(void)
 {
-        void *p = slob_alloc(PAGE_SIZE, 0, PAGE_SIZE-1);
-
-        if (p)
-                free_page((unsigned long)p);
-
-        mod_timer(&slob_timer, jiffies + HZ);
+        slob_ready = 1;
 }