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authorChristoph Lameter <cl@linux.com>2011-07-14 17:49:12 (GMT)
committerPekka Enberg <penberg@kernel.org>2011-07-18 12:17:02 (GMT)
commit1d07171c5e58e68a76a141970a3a5e816a414ce6 (patch)
tree9a8dcbf464b150d68daf0295e1ce644c1ec6d987
parent013e896373fc53f3d3c039364a25ccbd1fc0729a (diff)
downloadlinux-fsl-qoriq-1d07171c5e58e68a76a141970a3a5e816a414ce6.tar.xz
slub: disable interrupts in cmpxchg_double_slab when falling back to pagelock
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>
-rw-r--r--mm/slub.c49
1 files changed, 45 insertions, 4 deletions
diff --git a/mm/slub.c b/mm/slub.c
index 78c4882..7836b45 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -354,6 +354,42 @@ static __always_inline void slab_unlock(struct page *page)
__bit_spin_unlock(PG_locked, &page->flags);
}
+/* 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,
+ freelist_old, counters_old,
+ freelist_new, counters_new))
+ return 1;
+ } else
+#endif
+ {
+ slab_lock(page);
+ if (page->freelist == freelist_old && page->counters == counters_old) {
+ page->freelist = freelist_new;
+ page->counters = counters_new;
+ slab_unlock(page);
+ return 1;
+ }
+ slab_unlock(page);
+ }
+
+ 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;
+}
+
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,
@@ -368,14 +404,19 @@ static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
} 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();
@@ -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"));