The patch titled
NUMA slab allocator migration bugfix
has been added to the -mm tree. Its filename is
numa-slab-allocator-migration-bugfix.patch
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------------------------------------------------------
Subject: NUMA slab allocator migration bugfix
From: Joe Korty <joe.korty@xxxxxxxx>
NUMA slab allocator cpu migration bugfix
The NUMA slab allocator (specifically, cache_alloc_refill) is not refreshing
its local copies of what cpu and what numa node it is on, when it drops and
reacquires the irq block that it inherited from its caller. As a result those
values become invalid if an attempt to migrate the process to another numa
node occured while the irq block had been dropped.
The solution is to make cache_alloc_refill reload these variables whenever it
drops and reacquires the irq block.
The error is very difficult to hit. When it does occur, one gets the
following oops + stack traceback bits in check_spinlock_acquired:
kernel BUG at mm/slab.c:2417
cache_alloc_refill+0xe6
kmem_cache_alloc+0xd0
...
Signed-off-by: Joe Korty <joe.korty@xxxxxxxx>
Acked-by: Christoph Lameter <clameter@xxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/slab.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff -puN mm/slab.c~numa-slab-allocator-migration-bugfix mm/slab.c
--- a/mm/slab.c~numa-slab-allocator-migration-bugfix
+++ a/mm/slab.c
@@ -2960,11 +2960,10 @@ static void *cache_alloc_refill(struct k
struct array_cache *ac;
int node;
- node = numa_node_id();
-
+retry:
check_irq_off();
+ node = numa_node_id();
ac = cpu_cache_get(cachep);
-retry:
batchcount = ac->batchcount;
if (!ac->touched && batchcount > BATCHREFILL_LIMIT) {
/*
_
Patches currently in -mm which might be from joe.korty@xxxxxxxx are
numa-slab-allocator-migration-bugfix.patch
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