diff options
Diffstat (limited to 'mm/slob.c')
| -rw-r--r-- | mm/slob.c | 625 |
1 files changed, 0 insertions, 625 deletions
diff --git a/mm/slob.c b/mm/slob.c deleted file mode 100644 index 91bd3f2dd2f0..000000000000 --- a/mm/slob.c +++ /dev/null @@ -1,625 +0,0 @@ -/* - * SLOB Allocator: Simple List Of Blocks - * - * 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 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 set of 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. To reduce fragmentation, - * heap pages are segregated into three lists, with objects less than - * 256 bytes, objects less than 1024 bytes, and all other objects. - * - * Allocation from heap involves first searching for a page with - * sufficient free blocks (using a next-fit-like approach) followed by - * a first-fit scan of the page. Deallocation inserts objects back - * into the free list in address order, so this is effectively an - * address-ordered first fit. - * - * Above this is an implementation of kmalloc/kfree. Blocks returned - * 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 - * alloc_pages() directly, allocating compound pages so the page order - * does not have to be separately tracked. - * These objects are detected in kfree() because PageSlab() - * 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 - * 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_exact_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/swap.h> /* struct reclaim_state */ -#include <linux/cache.h> -#include <linux/init.h> -#include <linux/export.h> -#include <linux/rcupdate.h> -#include <linux/list.h> -#include <linux/kmemleak.h> - -#include <trace/events/kmem.h> - -#include <linux/atomic.h> - -#include "slab.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 { - slobidx_t units; -}; -typedef struct slob_block slob_t; - -/* - * All partially free slob pages go on these lists. - */ -#define SLOB_BREAK1 256 -#define SLOB_BREAK2 1024 -static LIST_HEAD(free_slob_small); -static LIST_HEAD(free_slob_medium); -static LIST_HEAD(free_slob_large); - -/* - * slob_page_free: true for pages on free_slob_pages list. - */ -static inline int slob_page_free(struct page *sp) -{ - return PageSlobFree(sp); -} - -static void set_slob_page_free(struct page *sp, struct list_head *list) -{ - list_add(&sp->list, list); - __SetPageSlobFree(sp); -} - -static inline void clear_slob_page_free(struct page *sp) -{ - list_del(&sp->list); - __ClearPageSlobFree(sp); -} - -#define SLOB_UNIT sizeof(slob_t) -#define SLOB_UNITS(size) DIV_ROUND_UP(size, SLOB_UNIT) - -/* - * 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 - * the block using call_rcu. - */ -struct slob_rcu { - struct rcu_head head; - int size; -}; - -/* - * slob_lock protects all slob allocator structures. - */ -static DEFINE_SPINLOCK(slob_lock); - -/* - * 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; -} - -/* - * 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_pages(gfp_t gfp, int order, int node) -{ - void *page; - -#ifdef CONFIG_NUMA - if (node != NUMA_NO_NODE) - page = alloc_pages_exact_node(node, gfp, order); - else -#endif - page = alloc_pages(gfp, order); - - if (!page) - return NULL; - - return page_address(page); -} - -static void slob_free_pages(void *b, int order) -{ - if (current->reclaim_state) - current->reclaim_state->reclaimed_slab += 1 << order; - free_pages((unsigned long)b, order); -} - -/* - * Allocate a slob block within a given slob_page sp. - */ -static void *slob_page_alloc(struct page *sp, size_t size, int align) -{ - slob_t *prev, *cur, *aligned = NULL; - int delta = 0, units = SLOB_UNITS(size); - - for (prev = NULL, cur = sp->freelist; ; 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 (avail >= units + delta) { /* room enough? */ - slob_t *next; - - if (delta) { /* need to fragment head to align? */ - next = slob_next(cur); - set_slob(aligned, avail - delta, next); - set_slob(cur, delta, aligned); - prev = cur; - cur = aligned; - avail = slob_units(cur); - } - - next = slob_next(cur); - if (avail == units) { /* exact fit? unlink. */ - if (prev) - set_slob(prev, slob_units(prev), next); - else - sp->freelist = next; - } else { /* fragment */ - if (prev) - set_slob(prev, slob_units(prev), cur + units); - else - sp->freelist = cur + units; - set_slob(cur + units, avail - units, next); - } - - sp->units -= units; - if (!sp->units) - clear_slob_page_free(sp); - return cur; - } - if (slob_last(cur)) - return NULL; - } -} - -/* - * slob_alloc: entry point into the slob allocator. - */ -static void *slob_alloc(size_t size, gfp_t gfp, int align, int node) -{ - struct page *sp; - struct list_head *prev; - struct list_head *slob_list; - slob_t *b = NULL; - unsigned long flags; - - if (size < SLOB_BREAK1) - slob_list = &free_slob_small; - else if (size < SLOB_BREAK2) - slob_list = &free_slob_medium; - else - slob_list = &free_slob_large; - - spin_lock_irqsave(&slob_lock, flags); - /* Iterate through each partially free page, try to find room */ - list_for_each_entry(sp, slob_list, 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 != NUMA_NO_NODE && page_to_nid(sp) != node) - continue; -#endif - /* Enough room on this page? */ - if (sp->units < SLOB_UNITS(size)) - continue; - - /* Attempt to alloc */ - prev = sp->list.prev; - b = slob_page_alloc(sp, size, align); - if (!b) - continue; - - /* Improve fragment distribution and reduce our average - * search time by starting our next search here. (see - * Knuth vol 1, sec 2.5, pg 449) */ - if (prev != slob_list->prev && - slob_list->next != prev->next) - list_move_tail(slob_list, prev->next); - break; - } - spin_unlock_irqrestore(&slob_lock, flags); - - /* Not enough space: must allocate a new page */ - if (!b) { - b = slob_new_pages(gfp & ~__GFP_ZERO, 0, node); - if (!b) - return NULL; - sp = virt_to_page(b); - __SetPageSlab(sp); - - spin_lock_irqsave(&slob_lock, flags); - sp->units = SLOB_UNITS(PAGE_SIZE); - sp->freelist = b; - INIT_LIST_HEAD(&sp->list); - set_slob(b, SLOB_UNITS(PAGE_SIZE), b + SLOB_UNITS(PAGE_SIZE)); - set_slob_page_free(sp, slob_list); - b = slob_page_alloc(sp, size, align); - BUG_ON(!b); - spin_unlock_irqrestore(&slob_lock, flags); - } - if (unlikely((gfp & __GFP_ZERO) && b)) - memset(b, 0, size); - return b; -} - -/* - * slob_free: entry point into the slob allocator. - */ -static void slob_free(void *block, int size) -{ - struct page *sp; - slob_t *prev, *next, *b = (slob_t *)block; - slobidx_t units; - unsigned long flags; - struct list_head *slob_list; - - if (unlikely(ZERO_OR_NULL_PTR(block))) - return; - BUG_ON(!size); - - sp = virt_to_page(block); - units = SLOB_UNITS(size); - - spin_lock_irqsave(&slob_lock, flags); - - 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); - spin_unlock_irqrestore(&slob_lock, flags); - __ClearPageSlab(sp); - page_mapcount_reset(sp); - slob_free_pages(b, 0); - return; - } - - if (!slob_page_free(sp)) { - /* This slob page is about to become partially free. Easy! */ - sp->units = units; - sp->freelist = b; - set_slob(b, units, - (void *)((unsigned long)(b + - SLOB_UNITS(PAGE_SIZE)) & PAGE_MASK)); - if (size < SLOB_BREAK1) - slob_list = &free_slob_small; - else if (size < SLOB_BREAK2) - slob_list = &free_slob_medium; - else - slob_list = &free_slob_large; - set_slob_page_free(sp, slob_list); - goto out; - } - - /* - * Otherwise the page is already partially free, so find reinsertion - * point. - */ - sp->units += units; - - if (b < (slob_t *)sp->freelist) { - if (b + units == sp->freelist) { - units += slob_units(sp->freelist); - sp->freelist = slob_next(sp->freelist); - } - set_slob(b, units, sp->freelist); - sp->freelist = b; - } else { - prev = sp->freelist; - 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); -} - -/* - * End of slob allocator proper. Begin kmem_cache_alloc and kmalloc frontend. - */ - -static __always_inline void * -__do_kmalloc_node(size_t size, gfp_t gfp, int node, unsigned long caller) -{ - unsigned int *m; - int align = max_t(size_t, ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN); - void *ret; - - gfp &= gfp_allowed_mask; - - lockdep_trace_alloc(gfp); - - if (size < PAGE_SIZE - align) { - if (!size) - return ZERO_SIZE_PTR; - - m = slob_alloc(size + align, gfp, align, node); - - if (!m) - return NULL; - *m = size; - ret = (void *)m + align; - - trace_kmalloc_node(caller, ret, - size, size + align, gfp, node); - } else { - unsigned int order = get_order(size); - - if (likely(order)) - gfp |= __GFP_COMP; - ret = slob_new_pages(gfp, order, node); - - trace_kmalloc_node(caller, ret, - size, PAGE_SIZE << order, gfp, node); - } - - kmemleak_alloc(ret, size, 1, gfp); - return ret; -} - -void *__kmalloc_node(size_t size, gfp_t gfp, int node) -{ - return __do_kmalloc_node(size, gfp, node, _RET_IP_); -} -EXPORT_SYMBOL(__kmalloc_node); - -#ifdef CONFIG_TRACING -void *__kmalloc_track_caller(size_t size, gfp_t gfp, unsigned long caller) -{ - return __do_kmalloc_node(size, gfp, NUMA_NO_NODE, caller); -} - -#ifdef CONFIG_NUMA -void *__kmalloc_node_track_caller(size_t size, gfp_t gfp, - int node, unsigned long caller) -{ - return __do_kmalloc_node(size, gfp, node, caller); -} -#endif -#endif - -void kfree(const void *block) -{ - struct page *sp; - - trace_kfree(_RET_IP_, block); - - if (unlikely(ZERO_OR_NULL_PTR(block))) - return; - kmemleak_free(block); - - sp = virt_to_page(block); - if (PageSlab(sp)) { - int align = max_t(size_t, ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN); - unsigned int *m = (unsigned int *)(block - align); - slob_free(m, *m + align); - } else - __free_pages(sp, compound_order(sp)); -} -EXPORT_SYMBOL(kfree); - -/* can't use ksize for kmem_cache_alloc memory, only kmalloc */ -size_t ksize(const void *block) -{ - struct page *sp; - int align; - unsigned int *m; - - BUG_ON(!block); - if (unlikely(block == ZERO_SIZE_PTR)) - return 0; - - sp = virt_to_page(block); - if (unlikely(!PageSlab(sp))) - return PAGE_SIZE << compound_order(sp); - - align = max_t(size_t, ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN); - m = (unsigned int *)(block - align); - return SLOB_UNITS(*m) * SLOB_UNIT; -} -EXPORT_SYMBOL(ksize); - -int __kmem_cache_create(struct kmem_cache *c, unsigned long flags) -{ - if (flags & SLAB_DESTROY_BY_RCU) { - /* leave room for rcu footer at the end of object */ - c->size += sizeof(struct slob_rcu); - } - c->flags = flags; - return 0; -} - -void *kmem_cache_alloc_node(struct kmem_cache *c, gfp_t flags, int node) -{ - void *b; - - flags &= gfp_allowed_mask; - - lockdep_trace_alloc(flags); - - if (c->size < PAGE_SIZE) { - b = slob_alloc(c->size, flags, c->align, node); - trace_kmem_cache_alloc_node(_RET_IP_, b, c->object_size, - SLOB_UNITS(c->size) * SLOB_UNIT, - flags, node); - } else { - b = slob_new_pages(flags, get_order(c->size), node); - trace_kmem_cache_alloc_node(_RET_IP_, b, c->object_size, - PAGE_SIZE << get_order(c->size), - flags, node); - } - - if (b && c->ctor) - c->ctor(b); - - kmemleak_alloc_recursive(b, c->size, 1, c->flags, flags); - return b; -} -EXPORT_SYMBOL(kmem_cache_alloc_node); - -static void __kmem_cache_free(void *b, int size) -{ - if (size < PAGE_SIZE) - slob_free(b, size); - else - slob_free_pages(b, get_order(size)); -} - -static void kmem_rcu_free(struct rcu_head *head) -{ - struct slob_rcu *slob_rcu = (struct slob_rcu *)head; - void *b = (void *)slob_rcu - (slob_rcu->size - sizeof(struct slob_rcu)); - - __kmem_cache_free(b, slob_rcu->size); -} - -void kmem_cache_free(struct kmem_cache *c, void *b) -{ - kmemleak_free_recursive(b, c->flags); - if (unlikely(c->flags & SLAB_DESTROY_BY_RCU)) { - struct slob_rcu *slob_rcu; - slob_rcu = b + (c->size - sizeof(struct slob_rcu)); - slob_rcu->size = c->size; - call_rcu(&slob_rcu->head, kmem_rcu_free); - } else { - __kmem_cache_free(b, c->size); - } - - trace_kmem_cache_free(_RET_IP_, b); -} -EXPORT_SYMBOL(kmem_cache_free); - -int __kmem_cache_shutdown(struct kmem_cache *c) -{ - /* No way to check for remaining objects */ - return 0; -} - -int kmem_cache_shrink(struct kmem_cache *d) -{ - return 0; -} -EXPORT_SYMBOL(kmem_cache_shrink); - -struct kmem_cache kmem_cache_boot = { - .name = "kmem_cache", - .size = sizeof(struct kmem_cache), - .flags = SLAB_PANIC, - .align = ARCH_KMALLOC_MINALIGN, -}; - -void __init kmem_cache_init(void) -{ - kmem_cache = &kmem_cache_boot; - slab_state = UP; -} - -void __init kmem_cache_init_late(void) -{ - slab_state = FULL; -} |