diff options
| -rw-r--r-- | Documentation/vm/slub.txt | 10 | ||||
| -rw-r--r-- | include/linux/slob_def.h | 5 | ||||
| -rw-r--r-- | include/linux/slub_def.h | 8 | ||||
| -rw-r--r-- | mm/slob.c | 5 | ||||
| -rw-r--r-- | mm/slub.c | 82 |
5 files changed, 85 insertions, 25 deletions
diff --git a/Documentation/vm/slub.txt b/Documentation/vm/slub.txt index bb1f5c6e28b3..510917ff59ed 100644 --- a/Documentation/vm/slub.txt +++ b/Documentation/vm/slub.txt @@ -41,6 +41,8 @@ Possible debug options are P Poisoning (object and padding) U User tracking (free and alloc) T Trace (please only use on single slabs) + O Switch debugging off for caches that would have + caused higher minimum slab orders - Switch all debugging off (useful if the kernel is configured with CONFIG_SLUB_DEBUG_ON) @@ -59,6 +61,14 @@ to the dentry cache with slub_debug=F,dentry +Debugging options may require the minimum possible slab order to increase as +a result of storing the metadata (for example, caches with PAGE_SIZE object +sizes). This has a higher liklihood of resulting in slab allocation errors +in low memory situations or if there's high fragmentation of memory. To +switch off debugging for such caches by default, use + + slub_debug=O + In case you forgot to enable debugging on the kernel command line: It is possible to enable debugging manually when the kernel is up. Look at the contents of: diff --git a/include/linux/slob_def.h b/include/linux/slob_def.h index bb5368df4be8..0ec00b39d006 100644 --- a/include/linux/slob_def.h +++ b/include/linux/slob_def.h @@ -34,9 +34,4 @@ static __always_inline void *__kmalloc(size_t size, gfp_t flags) return kmalloc(size, flags); } -static inline void kmem_cache_init_late(void) -{ - /* Nothing to do */ -} - #endif /* __LINUX_SLOB_DEF_H */ diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h index c1c862b1d01a..5ad70a60fd74 100644 --- a/include/linux/slub_def.h +++ b/include/linux/slub_def.h @@ -153,12 +153,10 @@ static __always_inline int kmalloc_index(size_t size) if (size <= KMALLOC_MIN_SIZE) return KMALLOC_SHIFT_LOW; -#if KMALLOC_MIN_SIZE <= 64 - if (size > 64 && size <= 96) + if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96) return 1; - if (size > 128 && size <= 192) + if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192) return 2; -#endif if (size <= 8) return 3; if (size <= 16) return 4; if (size <= 32) return 5; @@ -304,6 +302,4 @@ static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node) } #endif -void __init kmem_cache_init_late(void); - #endif /* _LINUX_SLUB_DEF_H */ diff --git a/mm/slob.c b/mm/slob.c index 9641da3d5e58..837ebd64cc34 100644 --- a/mm/slob.c +++ b/mm/slob.c @@ -692,3 +692,8 @@ void __init kmem_cache_init(void) { slob_ready = 1; } + +void __init kmem_cache_init_late(void) +{ + /* Nothing to do */ +} diff --git a/mm/slub.c b/mm/slub.c index b6276753626e..417ed843b251 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -141,6 +141,13 @@ SLAB_POISON | SLAB_STORE_USER) /* + * Debugging flags that require metadata to be stored in the slab. These get + * disabled when slub_debug=O is used and a cache's min order increases with + * metadata. + */ +#define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER) + +/* * Set of flags that will prevent slab merging */ #define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \ @@ -325,6 +332,7 @@ static int slub_debug; #endif static char *slub_debug_slabs; +static int disable_higher_order_debug; /* * Object debugging @@ -646,7 +654,7 @@ static int slab_pad_check(struct kmem_cache *s, struct page *page) slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1); print_section("Padding", end - remainder, remainder); - restore_bytes(s, "slab padding", POISON_INUSE, start, end); + restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end); return 0; } @@ -976,6 +984,15 @@ static int __init setup_slub_debug(char *str) */ goto check_slabs; + if (tolower(*str) == 'o') { + /* + * Avoid enabling debugging on caches if its minimum order + * would increase as a result. + */ + disable_higher_order_debug = 1; + goto out; + } + slub_debug = 0; if (*str == '-') /* @@ -1026,8 +1043,8 @@ static unsigned long kmem_cache_flags(unsigned long objsize, * Enable debugging if selected on the kernel commandline. */ if (slub_debug && (!slub_debug_slabs || - strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs)) == 0)) - flags |= slub_debug; + !strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs)))) + flags |= slub_debug; return flags; } @@ -1109,8 +1126,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) } if (kmemcheck_enabled - && !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) - { + && !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) { int pages = 1 << oo_order(oo); kmemcheck_alloc_shadow(page, oo_order(oo), flags, node); @@ -1560,6 +1576,10 @@ slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid) "default order: %d, min order: %d\n", s->name, s->objsize, s->size, oo_order(s->oo), oo_order(s->min)); + if (oo_order(s->min) > get_order(s->objsize)) + printk(KERN_WARNING " %s debugging increased min order, use " + "slub_debug=O to disable.\n", s->name); + for_each_online_node(node) { struct kmem_cache_node *n = get_node(s, node); unsigned long nr_slabs; @@ -2001,7 +2021,7 @@ static inline int calculate_order(int size) return order; fraction /= 2; } - min_objects --; + min_objects--; } /* @@ -2400,6 +2420,7 @@ static int calculate_sizes(struct kmem_cache *s, int forced_order) * on bootup. */ align = calculate_alignment(flags, align, s->objsize); + s->align = align; /* * SLUB stores one object immediately after another beginning from @@ -2452,6 +2473,18 @@ static int kmem_cache_open(struct kmem_cache *s, gfp_t gfpflags, if (!calculate_sizes(s, -1)) goto error; + if (disable_higher_order_debug) { + /* + * Disable debugging flags that store metadata if the min slab + * order increased. + */ + if (get_order(s->size) > get_order(s->objsize)) { + s->flags &= ~DEBUG_METADATA_FLAGS; + s->offset = 0; + if (!calculate_sizes(s, -1)) + goto error; + } + } /* * The larger the object size is, the more pages we want on the partial @@ -2790,6 +2823,11 @@ static s8 size_index[24] = { 2 /* 192 */ }; +static inline int size_index_elem(size_t bytes) +{ + return (bytes - 1) / 8; +} + static struct kmem_cache *get_slab(size_t size, gfp_t flags) { int index; @@ -2798,7 +2836,7 @@ static struct kmem_cache *get_slab(size_t size, gfp_t flags) if (!size) return ZERO_SIZE_PTR; - index = size_index[(size - 1) / 8]; + index = size_index[size_index_elem(size)]; } else index = fls(size - 1); @@ -3156,10 +3194,12 @@ void __init kmem_cache_init(void) slab_state = PARTIAL; /* Caches that are not of the two-to-the-power-of size */ - if (KMALLOC_MIN_SIZE <= 64) { + if (KMALLOC_MIN_SIZE <= 32) { create_kmalloc_cache(&kmalloc_caches[1], "kmalloc-96", 96, GFP_NOWAIT); caches++; + } + if (KMALLOC_MIN_SIZE <= 64) { create_kmalloc_cache(&kmalloc_caches[2], "kmalloc-192", 192, GFP_NOWAIT); caches++; @@ -3186,17 +3226,28 @@ void __init kmem_cache_init(void) BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 || (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1))); - for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) - size_index[(i - 1) / 8] = KMALLOC_SHIFT_LOW; + for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) { + int elem = size_index_elem(i); + if (elem >= ARRAY_SIZE(size_index)) + break; + size_index[elem] = KMALLOC_SHIFT_LOW; + } - if (KMALLOC_MIN_SIZE == 128) { + if (KMALLOC_MIN_SIZE == 64) { + /* + * The 96 byte size cache is not used if the alignment + * is 64 byte. + */ + for (i = 64 + 8; i <= 96; i += 8) + size_index[size_index_elem(i)] = 7; + } else if (KMALLOC_MIN_SIZE == 128) { /* * The 192 byte sized cache is not used if the alignment * is 128 byte. Redirect kmalloc to use the 256 byte cache * instead. */ for (i = 128 + 8; i <= 192; i += 8) - size_index[(i - 1) / 8] = 8; + size_index[size_index_elem(i)] = 8; } slab_state = UP; @@ -4543,8 +4594,11 @@ static int sysfs_slab_add(struct kmem_cache *s) } err = sysfs_create_group(&s->kobj, &slab_attr_group); - if (err) + if (err) { + kobject_del(&s->kobj); + kobject_put(&s->kobj); return err; + } kobject_uevent(&s->kobj, KOBJ_ADD); if (!unmergeable) { /* Setup first alias */ @@ -4726,7 +4780,7 @@ static const struct file_operations proc_slabinfo_operations = { static int __init slab_proc_init(void) { - proc_create("slabinfo",S_IWUSR|S_IRUGO,NULL,&proc_slabinfo_operations); + proc_create("slabinfo", S_IRUGO, NULL, &proc_slabinfo_operations); return 0; } module_init(slab_proc_init); |