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-rw-r--r--Documentation/vm/slub.txt10
-rw-r--r--include/linux/slob_def.h5
-rw-r--r--include/linux/slub_def.h8
-rw-r--r--mm/slob.c5
-rw-r--r--mm/slub.c82
5 files changed, 85 insertions, 25 deletions
diff --git a/Documentation/vm/slub.txt b/Documentation/vm/slub.txt
index bb1f5c6e28b..510917ff59e 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 bb5368df4be..0ec00b39d00 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 c1c862b1d01..5ad70a60fd7 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 9641da3d5e5..837ebd64cc3 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 b6276753626..417ed843b25 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);
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-04 23:29:19 +0000