SLUB: add CONFIG_SLUB_DEBUG
CONFIG_SLUB_DEBUG can be used to switch off the debugging and sysfs components of SLUB. Thus SLUB will be able to replace SLOB. SLUB can arrange objects in a denser way than SLOB and the code size should be minimal without debugging and sysfs support. Note that CONFIG_SLUB_DEBUG is materially different from CONFIG_SLAB_DEBUG. CONFIG_SLAB_DEBUG is used to enable slab debugging in SLAB. SLUB enables debugging via a boot parameter. SLUB debug code should always be present. CONFIG_SLUB_DEBUG can be modified in the embedded config section. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Christoph Lameter
Linus Torvalds
parent
02cbc87446
commit
41ecc55b8a
@ -504,6 +504,15 @@ config VM_EVENT_COUNTERS
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on EMBEDDED systems. /proc/vmstat will only show page counts
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if VM event counters are disabled.
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config SLUB_DEBUG
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default y
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bool "Enable SLUB debugging support" if EMBEDDED
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help
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SLUB has extensive debug support features. Disabling these can
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result in significant savings in code size. This also disables
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SLUB sysfs support. /sys/slab will not exist and there will be
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no support for cache validation etc.
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choice
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prompt "Choose SLAB allocator"
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default SLAB
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189
mm/slub.c
189
mm/slub.c
@ -89,17 +89,25 @@
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static inline int SlabDebug(struct page *page)
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{
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#ifdef CONFIG_SLUB_DEBUG
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return PageError(page);
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#else
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return 0;
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#endif
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}
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static inline void SetSlabDebug(struct page *page)
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{
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#ifdef CONFIG_SLUB_DEBUG
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SetPageError(page);
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#endif
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}
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static inline void ClearSlabDebug(struct page *page)
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{
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#ifdef CONFIG_SLUB_DEBUG
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ClearPageError(page);
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#endif
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}
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/*
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@ -207,7 +215,7 @@ struct track {
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enum track_item { TRACK_ALLOC, TRACK_FREE };
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#ifdef CONFIG_SYSFS
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#if defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG)
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static int sysfs_slab_add(struct kmem_cache *);
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static int sysfs_slab_alias(struct kmem_cache *, const char *);
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static void sysfs_slab_remove(struct kmem_cache *);
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@ -284,6 +292,14 @@ static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
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return (p - addr) / s->size;
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}
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#ifdef CONFIG_SLUB_DEBUG
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/*
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* Debug settings:
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*/
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static int slub_debug;
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static char *slub_debug_slabs;
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/*
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* Object debugging
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*/
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@ -821,6 +837,97 @@ static void trace(struct kmem_cache *s, struct page *page, void *object, int all
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}
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}
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static int __init setup_slub_debug(char *str)
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{
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if (!str || *str != '=')
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slub_debug = DEBUG_DEFAULT_FLAGS;
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else {
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str++;
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if (*str == 0 || *str == ',')
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slub_debug = DEBUG_DEFAULT_FLAGS;
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else
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for( ;*str && *str != ','; str++)
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switch (*str) {
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case 'f' : case 'F' :
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slub_debug |= SLAB_DEBUG_FREE;
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break;
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case 'z' : case 'Z' :
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slub_debug |= SLAB_RED_ZONE;
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break;
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case 'p' : case 'P' :
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slub_debug |= SLAB_POISON;
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break;
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case 'u' : case 'U' :
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slub_debug |= SLAB_STORE_USER;
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break;
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case 't' : case 'T' :
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slub_debug |= SLAB_TRACE;
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break;
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default:
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printk(KERN_ERR "slub_debug option '%c' "
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"unknown. skipped\n",*str);
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}
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}
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if (*str == ',')
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slub_debug_slabs = str + 1;
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return 1;
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}
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__setup("slub_debug", setup_slub_debug);
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static void kmem_cache_open_debug_check(struct kmem_cache *s)
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{
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/*
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* The page->offset field is only 16 bit wide. This is an offset
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* in units of words from the beginning of an object. If the slab
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* size is bigger then we cannot move the free pointer behind the
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* object anymore.
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*
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* On 32 bit platforms the limit is 256k. On 64bit platforms
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* the limit is 512k.
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*
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* Debugging or ctor/dtors may create a need to move the free
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* pointer. Fail if this happens.
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*/
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if (s->size >= 65535 * sizeof(void *)) {
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BUG_ON(s->flags & (SLAB_RED_ZONE | SLAB_POISON |
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SLAB_STORE_USER | SLAB_DESTROY_BY_RCU));
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BUG_ON(s->ctor || s->dtor);
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}
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else
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/*
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* Enable debugging if selected on the kernel commandline.
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*/
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if (slub_debug && (!slub_debug_slabs ||
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strncmp(slub_debug_slabs, s->name,
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strlen(slub_debug_slabs)) == 0))
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s->flags |= slub_debug;
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}
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#else
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static inline int alloc_object_checks(struct kmem_cache *s,
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struct page *page, void *object) { return 0; }
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static inline int free_object_checks(struct kmem_cache *s,
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struct page *page, void *object) { return 0; }
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static inline void add_full(struct kmem_cache_node *n, struct page *page) {}
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static inline void remove_full(struct kmem_cache *s, struct page *page) {}
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static inline void trace(struct kmem_cache *s, struct page *page,
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void *object, int alloc) {}
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static inline void init_object(struct kmem_cache *s,
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void *object, int active) {}
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static inline void init_tracking(struct kmem_cache *s, void *object) {}
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static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
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{ return 1; }
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static inline int check_object(struct kmem_cache *s, struct page *page,
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void *object, int active) { return 1; }
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static inline void set_track(struct kmem_cache *s, void *object,
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enum track_item alloc, void *addr) {}
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static inline void kmem_cache_open_debug_check(struct kmem_cache *s) {}
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#define slub_debug 0
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#endif
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/*
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* Slab allocation and freeing
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*/
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@ -1445,13 +1552,6 @@ static int slub_min_objects = DEFAULT_MIN_OBJECTS;
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*/
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static int slub_nomerge;
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/*
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* Debug settings:
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*/
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static int slub_debug;
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static char *slub_debug_slabs;
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/*
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* Calculate the order of allocation given an slab object size.
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*
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@ -1660,6 +1760,7 @@ static int calculate_sizes(struct kmem_cache *s)
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*/
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size = ALIGN(size, sizeof(void *));
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#ifdef CONFIG_SLUB_DEBUG
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/*
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* If we are Redzoning then check if there is some space between the
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* end of the object and the free pointer. If not then add an
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@ -1667,6 +1768,7 @@ static int calculate_sizes(struct kmem_cache *s)
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*/
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if ((flags & SLAB_RED_ZONE) && size == s->objsize)
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size += sizeof(void *);
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#endif
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/*
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* With that we have determined the number of bytes in actual use
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@ -1674,6 +1776,7 @@ static int calculate_sizes(struct kmem_cache *s)
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*/
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s->inuse = size;
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#ifdef CONFIG_SLUB_DEBUG
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if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
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s->ctor || s->dtor)) {
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/*
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@ -1704,6 +1807,7 @@ static int calculate_sizes(struct kmem_cache *s)
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* of the object.
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*/
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size += sizeof(void *);
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#endif
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/*
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* Determine the alignment based on various parameters that the
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@ -1753,32 +1857,7 @@ static int kmem_cache_open(struct kmem_cache *s, gfp_t gfpflags,
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s->objsize = size;
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s->flags = flags;
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s->align = align;
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/*
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* The page->offset field is only 16 bit wide. This is an offset
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* in units of words from the beginning of an object. If the slab
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* size is bigger then we cannot move the free pointer behind the
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* object anymore.
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*
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* On 32 bit platforms the limit is 256k. On 64bit platforms
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* the limit is 512k.
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*
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* Debugging or ctor/dtors may create a need to move the free
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* pointer. Fail if this happens.
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*/
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if (s->size >= 65535 * sizeof(void *)) {
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BUG_ON(flags & (SLAB_RED_ZONE | SLAB_POISON |
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SLAB_STORE_USER | SLAB_DESTROY_BY_RCU));
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BUG_ON(ctor || dtor);
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}
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else
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/*
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* Enable debugging if selected on the kernel commandline.
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*/
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if (slub_debug && (!slub_debug_slabs ||
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strncmp(slub_debug_slabs, name,
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strlen(slub_debug_slabs)) == 0))
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s->flags |= slub_debug;
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kmem_cache_open_debug_check(s);
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if (!calculate_sizes(s))
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goto error;
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@ -1949,45 +2028,6 @@ static int __init setup_slub_nomerge(char *str)
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__setup("slub_nomerge", setup_slub_nomerge);
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static int __init setup_slub_debug(char *str)
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{
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if (!str || *str != '=')
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slub_debug = DEBUG_DEFAULT_FLAGS;
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else {
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str++;
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if (*str == 0 || *str == ',')
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slub_debug = DEBUG_DEFAULT_FLAGS;
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else
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for( ;*str && *str != ','; str++)
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switch (*str) {
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case 'f' : case 'F' :
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slub_debug |= SLAB_DEBUG_FREE;
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break;
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case 'z' : case 'Z' :
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slub_debug |= SLAB_RED_ZONE;
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break;
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case 'p' : case 'P' :
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slub_debug |= SLAB_POISON;
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break;
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case 'u' : case 'U' :
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slub_debug |= SLAB_STORE_USER;
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break;
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case 't' : case 'T' :
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slub_debug |= SLAB_TRACE;
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break;
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default:
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printk(KERN_ERR "slub_debug option '%c' "
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"unknown. skipped\n",*str);
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}
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}
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if (*str == ',')
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slub_debug_slabs = str + 1;
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return 1;
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}
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__setup("slub_debug", setup_slub_debug);
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static struct kmem_cache *create_kmalloc_cache(struct kmem_cache *s,
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const char *name, int size, gfp_t gfp_flags)
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{
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@ -2554,8 +2594,7 @@ void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
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return slab_alloc(s, gfpflags, node, caller);
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}
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#ifdef CONFIG_SYSFS
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#if defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG)
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static int validate_slab(struct kmem_cache *s, struct page *page)
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{
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void *p;
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