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slub: disable interrupts in cmpxchg_double_slab when falling back to pagelock

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Split cmpxchg_double_slab into two functions. One for the case where we know that
interrupts are disabled (and therefore the fallback does not need to disable
interrupts) and one for the other cases where fallback will also disable interrupts.

This fixes the issue that __slab_free called cmpxchg_double_slab in some scenarios
without disabling interrupts.

Tested-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
This commit is contained in:
Christoph Lameter 2011-07-14 12:49:12 -05:00 committed by Pekka Enberg
parent 013e896373
commit 1d07171c5e
1 changed files with 46 additions and 5 deletions
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51
mm/slub.c
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@ -354,11 +354,13 @@ static __always_inline void slab_unlock(struct page *page)
__bit_spin_unlock(PG_locked, &page->flags);
}
static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
/* Interrupts must be disabled (for the fallback code to work right) */
static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
void *freelist_old, unsigned long counters_old,
void *freelist_new, unsigned long counters_new,
const char *n)
{
VM_BUG_ON(!irqs_disabled());
#ifdef CONFIG_CMPXCHG_DOUBLE
if (s->flags & __CMPXCHG_DOUBLE) {
if (cmpxchg_double(&page->freelist,
@ -388,6 +390,45 @@ static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
return 0;
}
static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
void *freelist_old, unsigned long counters_old,
void *freelist_new, unsigned long counters_new,
const char *n)
{
#ifdef CONFIG_CMPXCHG_DOUBLE
if (s->flags & __CMPXCHG_DOUBLE) {
if (cmpxchg_double(&page->freelist,
freelist_old, counters_old,
freelist_new, counters_new))
return 1;
} else
#endif
{
unsigned long flags;
local_irq_save(flags);
slab_lock(page);
if (page->freelist == freelist_old && page->counters == counters_old) {
page->freelist = freelist_new;
page->counters = counters_new;
slab_unlock(page);
local_irq_restore(flags);
return 1;
}
slab_unlock(page);
local_irq_restore(flags);
}
cpu_relax();
stat(s, CMPXCHG_DOUBLE_FAIL);
#ifdef SLUB_DEBUG_CMPXCHG
printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
#endif
return 0;
}
#ifdef CONFIG_SLUB_DEBUG
/*
* Determine a map of object in use on a page.
@ -1471,7 +1512,7 @@ static inline int acquire_slab(struct kmem_cache *s,
VM_BUG_ON(new.frozen);
new.frozen = 1;
} while (!cmpxchg_double_slab(s, page,
} while (!__cmpxchg_double_slab(s, page,
freelist, counters,
NULL, new.counters,
"lock and freeze"));
@ -1709,7 +1750,7 @@ static void deactivate_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
new.inuse--;
VM_BUG_ON(!new.frozen);
} while (!cmpxchg_double_slab(s, page,
} while (!__cmpxchg_double_slab(s, page,
prior, counters,
freelist, new.counters,
"drain percpu freelist"));
@ -1798,7 +1839,7 @@ redo:
}
l = m;
if (!cmpxchg_double_slab(s, page,
if (!__cmpxchg_double_slab(s, page,
old.freelist, old.counters,
new.freelist, new.counters,
"unfreezing slab"))
@ -1992,7 +2033,7 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
new.inuse = page->objects;
new.frozen = object != NULL;
} while (!cmpxchg_double_slab(s, page,
} while (!__cmpxchg_double_slab(s, page,
object, counters,
NULL, new.counters,
"__slab_alloc"));