![Christoph Lameter](/assets/img/avatar_default.png)
Add some comments explaining the fields of the kmem_cache_cpu structure. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
207 lines
5.1 KiB
C
207 lines
5.1 KiB
C
#ifndef _LINUX_SLUB_DEF_H
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#define _LINUX_SLUB_DEF_H
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/*
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* SLUB : A Slab allocator without object queues.
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*
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* (C) 2007 SGI, Christoph Lameter <clameter@sgi.com>
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*/
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#include <linux/types.h>
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#include <linux/gfp.h>
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#include <linux/workqueue.h>
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#include <linux/kobject.h>
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struct kmem_cache_cpu {
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void **freelist; /* Pointer to first free per cpu object */
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struct page *page; /* The slab from which we are allocating */
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int node; /* The node of the page (or -1 for debug) */
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unsigned int offset; /* Freepointer offset (in word units) */
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unsigned int objsize; /* Size of an object (from kmem_cache) */
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};
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struct kmem_cache_node {
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spinlock_t list_lock; /* Protect partial list and nr_partial */
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unsigned long nr_partial;
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atomic_long_t nr_slabs;
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struct list_head partial;
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#ifdef CONFIG_SLUB_DEBUG
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struct list_head full;
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#endif
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};
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/*
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* Slab cache management.
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*/
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struct kmem_cache {
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/* Used for retriving partial slabs etc */
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unsigned long flags;
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int size; /* The size of an object including meta data */
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int objsize; /* The size of an object without meta data */
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int offset; /* Free pointer offset. */
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int order;
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/*
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* Avoid an extra cache line for UP, SMP and for the node local to
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* struct kmem_cache.
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*/
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struct kmem_cache_node local_node;
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/* Allocation and freeing of slabs */
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int objects; /* Number of objects in slab */
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int refcount; /* Refcount for slab cache destroy */
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void (*ctor)(struct kmem_cache *, void *);
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int inuse; /* Offset to metadata */
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int align; /* Alignment */
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const char *name; /* Name (only for display!) */
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struct list_head list; /* List of slab caches */
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#ifdef CONFIG_SLUB_DEBUG
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struct kobject kobj; /* For sysfs */
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#endif
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#ifdef CONFIG_NUMA
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/*
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* Defragmentation by allocating from a remote node.
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*/
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int remote_node_defrag_ratio;
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struct kmem_cache_node *node[MAX_NUMNODES];
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#endif
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#ifdef CONFIG_SMP
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struct kmem_cache_cpu *cpu_slab[NR_CPUS];
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#else
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struct kmem_cache_cpu cpu_slab;
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#endif
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};
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/*
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* Kmalloc subsystem.
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*/
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#if defined(ARCH_KMALLOC_MINALIGN) && ARCH_KMALLOC_MINALIGN > 8
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#define KMALLOC_MIN_SIZE ARCH_KMALLOC_MINALIGN
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#else
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#define KMALLOC_MIN_SIZE 8
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#endif
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#define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
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/*
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* We keep the general caches in an array of slab caches that are used for
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* 2^x bytes of allocations.
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*/
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extern struct kmem_cache kmalloc_caches[PAGE_SHIFT];
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/*
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* Sorry that the following has to be that ugly but some versions of GCC
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* have trouble with constant propagation and loops.
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*/
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static __always_inline int kmalloc_index(size_t size)
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{
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if (!size)
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return 0;
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if (size <= KMALLOC_MIN_SIZE)
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return KMALLOC_SHIFT_LOW;
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if (size > 64 && size <= 96)
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return 1;
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if (size > 128 && size <= 192)
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return 2;
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if (size <= 8) return 3;
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if (size <= 16) return 4;
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if (size <= 32) return 5;
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if (size <= 64) return 6;
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if (size <= 128) return 7;
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if (size <= 256) return 8;
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if (size <= 512) return 9;
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if (size <= 1024) return 10;
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if (size <= 2 * 1024) return 11;
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/*
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* The following is only needed to support architectures with a larger page
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* size than 4k.
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*/
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if (size <= 4 * 1024) return 12;
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if (size <= 8 * 1024) return 13;
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if (size <= 16 * 1024) return 14;
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if (size <= 32 * 1024) return 15;
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if (size <= 64 * 1024) return 16;
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if (size <= 128 * 1024) return 17;
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if (size <= 256 * 1024) return 18;
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if (size <= 512 * 1024) return 19;
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if (size <= 1024 * 1024) return 20;
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if (size <= 2 * 1024 * 1024) return 21;
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return -1;
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/*
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* What we really wanted to do and cannot do because of compiler issues is:
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* int i;
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* for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
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* if (size <= (1 << i))
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* return i;
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*/
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}
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/*
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* Find the slab cache for a given combination of allocation flags and size.
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*
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* This ought to end up with a global pointer to the right cache
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* in kmalloc_caches.
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*/
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static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
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{
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int index = kmalloc_index(size);
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if (index == 0)
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return NULL;
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return &kmalloc_caches[index];
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}
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#ifdef CONFIG_ZONE_DMA
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#define SLUB_DMA __GFP_DMA
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#else
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/* Disable DMA functionality */
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#define SLUB_DMA (__force gfp_t)0
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#endif
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void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
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void *__kmalloc(size_t size, gfp_t flags);
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static __always_inline void *kmalloc(size_t size, gfp_t flags)
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{
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if (__builtin_constant_p(size)) {
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if (size > PAGE_SIZE / 2)
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return (void *)__get_free_pages(flags | __GFP_COMP,
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get_order(size));
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if (!(flags & SLUB_DMA)) {
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struct kmem_cache *s = kmalloc_slab(size);
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if (!s)
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return ZERO_SIZE_PTR;
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return kmem_cache_alloc(s, flags);
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}
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}
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return __kmalloc(size, flags);
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}
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#ifdef CONFIG_NUMA
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void *__kmalloc_node(size_t size, gfp_t flags, int node);
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void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
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static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
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{
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if (__builtin_constant_p(size) &&
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size <= PAGE_SIZE / 2 && !(flags & SLUB_DMA)) {
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struct kmem_cache *s = kmalloc_slab(size);
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if (!s)
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return ZERO_SIZE_PTR;
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return kmem_cache_alloc_node(s, flags, node);
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}
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return __kmalloc_node(size, flags, node);
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}
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#endif
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#endif /* _LINUX_SLUB_DEF_H */
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