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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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55834c5909
Quarantine isolates freed objects in a separate queue. The objects are returned to the allocator later, which helps to detect use-after-free errors. When the object is freed, its state changes from KASAN_STATE_ALLOC to KASAN_STATE_QUARANTINE. The object is poisoned and put into quarantine instead of being returned to the allocator, therefore every subsequent access to that object triggers a KASAN error, and the error handler is able to say where the object has been allocated and deallocated. When it's time for the object to leave quarantine, its state becomes KASAN_STATE_FREE and it's returned to the allocator. From now on the allocator may reuse it for another allocation. Before that happens, it's still possible to detect a use-after free on that object (it retains the allocation/deallocation stacks). When the allocator reuses this object, the shadow is unpoisoned and old allocation/deallocation stacks are wiped. Therefore a use of this object, even an incorrect one, won't trigger ASan warning. Without the quarantine, it's not guaranteed that the objects aren't reused immediately, that's why the probability of catching a use-after-free is lower than with quarantine in place. Quarantine isolates freed objects in a separate queue. The objects are returned to the allocator later, which helps to detect use-after-free errors. Freed objects are first added to per-cpu quarantine queues. When a cache is destroyed or memory shrinking is requested, the objects are moved into the global quarantine queue. Whenever a kmalloc call allows memory reclaiming, the oldest objects are popped out of the global queue until the total size of objects in quarantine is less than 3/4 of the maximum quarantine size (which is a fraction of installed physical memory). As long as an object remains in the quarantine, KASAN is able to report accesses to it, so the chance of reporting a use-after-free is increased. Once the object leaves quarantine, the allocator may reuse it, in which case the object is unpoisoned and KASAN can't detect incorrect accesses to it. Right now quarantine support is only enabled in SLAB allocator. Unification of KASAN features in SLAB and SLUB will be done later. This patch is based on the "mm: kasan: quarantine" patch originally prepared by Dmitry Chernenkov. A number of improvements have been suggested by Andrey Ryabinin. [glider@google.com: v9] Link: http://lkml.kernel.org/r/1462987130-144092-1-git-send-email-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Andrey Konovalov <adech.fo@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
468 lines
13 KiB
C
468 lines
13 KiB
C
#ifndef MM_SLAB_H
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#define MM_SLAB_H
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/*
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* Internal slab definitions
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*/
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#ifdef CONFIG_SLOB
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/*
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* Common fields provided in kmem_cache by all slab allocators
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* This struct is either used directly by the allocator (SLOB)
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* or the allocator must include definitions for all fields
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* provided in kmem_cache_common in their definition of kmem_cache.
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*
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* Once we can do anonymous structs (C11 standard) we could put a
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* anonymous struct definition in these allocators so that the
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* separate allocations in the kmem_cache structure of SLAB and
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* SLUB is no longer needed.
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*/
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struct kmem_cache {
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unsigned int object_size;/* The original size of the object */
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unsigned int size; /* The aligned/padded/added on size */
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unsigned int align; /* Alignment as calculated */
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unsigned long flags; /* Active flags on the slab */
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const char *name; /* Slab name for sysfs */
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int refcount; /* Use counter */
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void (*ctor)(void *); /* Called on object slot creation */
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struct list_head list; /* List of all slab caches on the system */
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};
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#endif /* CONFIG_SLOB */
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#ifdef CONFIG_SLAB
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#include <linux/slab_def.h>
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#endif
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#ifdef CONFIG_SLUB
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#include <linux/slub_def.h>
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#endif
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#include <linux/memcontrol.h>
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#include <linux/fault-inject.h>
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#include <linux/kmemcheck.h>
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#include <linux/kasan.h>
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#include <linux/kmemleak.h>
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/*
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* State of the slab allocator.
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*
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* This is used to describe the states of the allocator during bootup.
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* Allocators use this to gradually bootstrap themselves. Most allocators
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* have the problem that the structures used for managing slab caches are
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* allocated from slab caches themselves.
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*/
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enum slab_state {
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DOWN, /* No slab functionality yet */
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PARTIAL, /* SLUB: kmem_cache_node available */
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PARTIAL_NODE, /* SLAB: kmalloc size for node struct available */
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UP, /* Slab caches usable but not all extras yet */
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FULL /* Everything is working */
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};
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extern enum slab_state slab_state;
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/* The slab cache mutex protects the management structures during changes */
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extern struct mutex slab_mutex;
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/* The list of all slab caches on the system */
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extern struct list_head slab_caches;
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/* The slab cache that manages slab cache information */
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extern struct kmem_cache *kmem_cache;
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unsigned long calculate_alignment(unsigned long flags,
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unsigned long align, unsigned long size);
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#ifndef CONFIG_SLOB
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/* Kmalloc array related functions */
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void setup_kmalloc_cache_index_table(void);
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void create_kmalloc_caches(unsigned long);
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/* Find the kmalloc slab corresponding for a certain size */
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struct kmem_cache *kmalloc_slab(size_t, gfp_t);
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#endif
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/* Functions provided by the slab allocators */
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extern int __kmem_cache_create(struct kmem_cache *, unsigned long flags);
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extern struct kmem_cache *create_kmalloc_cache(const char *name, size_t size,
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unsigned long flags);
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extern void create_boot_cache(struct kmem_cache *, const char *name,
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size_t size, unsigned long flags);
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int slab_unmergeable(struct kmem_cache *s);
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struct kmem_cache *find_mergeable(size_t size, size_t align,
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unsigned long flags, const char *name, void (*ctor)(void *));
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#ifndef CONFIG_SLOB
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struct kmem_cache *
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__kmem_cache_alias(const char *name, size_t size, size_t align,
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unsigned long flags, void (*ctor)(void *));
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unsigned long kmem_cache_flags(unsigned long object_size,
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unsigned long flags, const char *name,
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void (*ctor)(void *));
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#else
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static inline struct kmem_cache *
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__kmem_cache_alias(const char *name, size_t size, size_t align,
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unsigned long flags, void (*ctor)(void *))
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{ return NULL; }
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static inline unsigned long kmem_cache_flags(unsigned long object_size,
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unsigned long flags, const char *name,
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void (*ctor)(void *))
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{
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return flags;
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}
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#endif
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/* Legal flag mask for kmem_cache_create(), for various configurations */
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#define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | SLAB_PANIC | \
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SLAB_DESTROY_BY_RCU | SLAB_DEBUG_OBJECTS )
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#if defined(CONFIG_DEBUG_SLAB)
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#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
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#elif defined(CONFIG_SLUB_DEBUG)
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#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
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SLAB_TRACE | SLAB_CONSISTENCY_CHECKS)
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#else
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#define SLAB_DEBUG_FLAGS (0)
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#endif
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#if defined(CONFIG_SLAB)
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#define SLAB_CACHE_FLAGS (SLAB_MEM_SPREAD | SLAB_NOLEAKTRACE | \
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SLAB_RECLAIM_ACCOUNT | SLAB_TEMPORARY | \
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SLAB_NOTRACK | SLAB_ACCOUNT)
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#elif defined(CONFIG_SLUB)
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#define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \
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SLAB_TEMPORARY | SLAB_NOTRACK | SLAB_ACCOUNT)
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#else
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#define SLAB_CACHE_FLAGS (0)
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#endif
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#define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS)
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int __kmem_cache_shutdown(struct kmem_cache *);
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void __kmem_cache_release(struct kmem_cache *);
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int __kmem_cache_shrink(struct kmem_cache *, bool);
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void slab_kmem_cache_release(struct kmem_cache *);
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struct seq_file;
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struct file;
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struct slabinfo {
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unsigned long active_objs;
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unsigned long num_objs;
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unsigned long active_slabs;
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unsigned long num_slabs;
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unsigned long shared_avail;
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unsigned int limit;
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unsigned int batchcount;
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unsigned int shared;
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unsigned int objects_per_slab;
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unsigned int cache_order;
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};
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void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo);
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void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s);
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ssize_t slabinfo_write(struct file *file, const char __user *buffer,
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size_t count, loff_t *ppos);
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/*
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* Generic implementation of bulk operations
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* These are useful for situations in which the allocator cannot
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* perform optimizations. In that case segments of the object listed
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* may be allocated or freed using these operations.
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*/
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void __kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
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int __kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
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#if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)
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/*
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* Iterate over all memcg caches of the given root cache. The caller must hold
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* slab_mutex.
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*/
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#define for_each_memcg_cache(iter, root) \
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list_for_each_entry(iter, &(root)->memcg_params.list, \
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memcg_params.list)
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static inline bool is_root_cache(struct kmem_cache *s)
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{
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return s->memcg_params.is_root_cache;
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}
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static inline bool slab_equal_or_root(struct kmem_cache *s,
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struct kmem_cache *p)
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{
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return p == s || p == s->memcg_params.root_cache;
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}
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/*
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* We use suffixes to the name in memcg because we can't have caches
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* created in the system with the same name. But when we print them
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* locally, better refer to them with the base name
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*/
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static inline const char *cache_name(struct kmem_cache *s)
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{
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if (!is_root_cache(s))
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s = s->memcg_params.root_cache;
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return s->name;
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}
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/*
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* Note, we protect with RCU only the memcg_caches array, not per-memcg caches.
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* That said the caller must assure the memcg's cache won't go away by either
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* taking a css reference to the owner cgroup, or holding the slab_mutex.
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*/
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static inline struct kmem_cache *
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cache_from_memcg_idx(struct kmem_cache *s, int idx)
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{
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struct kmem_cache *cachep;
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struct memcg_cache_array *arr;
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rcu_read_lock();
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arr = rcu_dereference(s->memcg_params.memcg_caches);
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/*
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* Make sure we will access the up-to-date value. The code updating
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* memcg_caches issues a write barrier to match this (see
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* memcg_create_kmem_cache()).
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*/
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cachep = lockless_dereference(arr->entries[idx]);
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rcu_read_unlock();
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return cachep;
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}
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static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
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{
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if (is_root_cache(s))
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return s;
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return s->memcg_params.root_cache;
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}
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static __always_inline int memcg_charge_slab(struct page *page,
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gfp_t gfp, int order,
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struct kmem_cache *s)
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{
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int ret;
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if (!memcg_kmem_enabled())
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return 0;
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if (is_root_cache(s))
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return 0;
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ret = __memcg_kmem_charge_memcg(page, gfp, order,
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s->memcg_params.memcg);
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if (ret)
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return ret;
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memcg_kmem_update_page_stat(page,
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(s->flags & SLAB_RECLAIM_ACCOUNT) ?
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MEMCG_SLAB_RECLAIMABLE : MEMCG_SLAB_UNRECLAIMABLE,
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1 << order);
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return 0;
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}
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static __always_inline void memcg_uncharge_slab(struct page *page, int order,
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struct kmem_cache *s)
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{
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memcg_kmem_update_page_stat(page,
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(s->flags & SLAB_RECLAIM_ACCOUNT) ?
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MEMCG_SLAB_RECLAIMABLE : MEMCG_SLAB_UNRECLAIMABLE,
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-(1 << order));
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memcg_kmem_uncharge(page, order);
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}
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extern void slab_init_memcg_params(struct kmem_cache *);
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#else /* CONFIG_MEMCG && !CONFIG_SLOB */
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#define for_each_memcg_cache(iter, root) \
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for ((void)(iter), (void)(root); 0; )
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static inline bool is_root_cache(struct kmem_cache *s)
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{
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return true;
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}
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static inline bool slab_equal_or_root(struct kmem_cache *s,
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struct kmem_cache *p)
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{
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return true;
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}
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static inline const char *cache_name(struct kmem_cache *s)
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{
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return s->name;
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}
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static inline struct kmem_cache *
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cache_from_memcg_idx(struct kmem_cache *s, int idx)
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{
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return NULL;
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}
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static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
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{
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return s;
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}
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static inline int memcg_charge_slab(struct page *page, gfp_t gfp, int order,
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struct kmem_cache *s)
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{
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return 0;
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}
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static inline void memcg_uncharge_slab(struct page *page, int order,
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struct kmem_cache *s)
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{
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}
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static inline void slab_init_memcg_params(struct kmem_cache *s)
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{
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}
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#endif /* CONFIG_MEMCG && !CONFIG_SLOB */
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static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
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{
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struct kmem_cache *cachep;
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struct page *page;
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/*
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* When kmemcg is not being used, both assignments should return the
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* same value. but we don't want to pay the assignment price in that
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* case. If it is not compiled in, the compiler should be smart enough
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* to not do even the assignment. In that case, slab_equal_or_root
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* will also be a constant.
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*/
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if (!memcg_kmem_enabled() &&
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!unlikely(s->flags & SLAB_CONSISTENCY_CHECKS))
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return s;
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page = virt_to_head_page(x);
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cachep = page->slab_cache;
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if (slab_equal_or_root(cachep, s))
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return cachep;
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pr_err("%s: Wrong slab cache. %s but object is from %s\n",
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__func__, s->name, cachep->name);
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WARN_ON_ONCE(1);
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return s;
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}
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static inline size_t slab_ksize(const struct kmem_cache *s)
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{
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#ifndef CONFIG_SLUB
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return s->object_size;
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#else /* CONFIG_SLUB */
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# ifdef CONFIG_SLUB_DEBUG
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/*
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* Debugging requires use of the padding between object
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* and whatever may come after it.
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*/
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if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
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return s->object_size;
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# endif
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/*
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* If we have the need to store the freelist pointer
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* back there or track user information then we can
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* only use the space before that information.
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*/
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if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
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return s->inuse;
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/*
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* Else we can use all the padding etc for the allocation
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*/
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return s->size;
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#endif
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}
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static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
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gfp_t flags)
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{
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flags &= gfp_allowed_mask;
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lockdep_trace_alloc(flags);
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might_sleep_if(gfpflags_allow_blocking(flags));
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if (should_failslab(s, flags))
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return NULL;
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return memcg_kmem_get_cache(s, flags);
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}
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static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
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size_t size, void **p)
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{
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size_t i;
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flags &= gfp_allowed_mask;
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for (i = 0; i < size; i++) {
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void *object = p[i];
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kmemcheck_slab_alloc(s, flags, object, slab_ksize(s));
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kmemleak_alloc_recursive(object, s->object_size, 1,
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s->flags, flags);
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kasan_slab_alloc(s, object, flags);
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}
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memcg_kmem_put_cache(s);
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}
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#ifndef CONFIG_SLOB
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/*
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* The slab lists for all objects.
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*/
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struct kmem_cache_node {
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spinlock_t list_lock;
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#ifdef CONFIG_SLAB
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struct list_head slabs_partial; /* partial list first, better asm code */
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struct list_head slabs_full;
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struct list_head slabs_free;
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unsigned long free_objects;
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unsigned int free_limit;
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unsigned int colour_next; /* Per-node cache coloring */
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struct array_cache *shared; /* shared per node */
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struct alien_cache **alien; /* on other nodes */
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unsigned long next_reap; /* updated without locking */
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int free_touched; /* updated without locking */
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#endif
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#ifdef CONFIG_SLUB
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unsigned long nr_partial;
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struct list_head partial;
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#ifdef CONFIG_SLUB_DEBUG
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atomic_long_t nr_slabs;
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atomic_long_t total_objects;
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struct list_head full;
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#endif
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#endif
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};
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static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
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{
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return s->node[node];
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}
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/*
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* Iterator over all nodes. The body will be executed for each node that has
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* a kmem_cache_node structure allocated (which is true for all online nodes)
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*/
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#define for_each_kmem_cache_node(__s, __node, __n) \
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for (__node = 0; __node < nr_node_ids; __node++) \
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if ((__n = get_node(__s, __node)))
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#endif
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void *slab_start(struct seq_file *m, loff_t *pos);
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void *slab_next(struct seq_file *m, void *p, loff_t *pos);
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void slab_stop(struct seq_file *m, void *p);
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int memcg_slab_show(struct seq_file *m, void *p);
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void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr);
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#endif /* MM_SLAB_H */
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