On Thu, 2017-11-09 at 09:49 -0600, Christopher Lameter wrote:
> On Thu, 9 Nov 2017, Miles Chen wrote:
>
> > In this fix patch, it disables slab merging if SLUB_DEBUG=O and
> > CONFIG_SLUB_DEBUG_ON=y but the debug features are disabled by the
> > disable_higher_order_debug logic and it holds the "slab merging is off
> > if any debug features are enabled" behavior.
>
> Sounds good. Where is the patch?
>
>
Sorry for confusing, I meant the original patch of this thread :-)
By checking disable_higher_order_debug & (slub_debug &
SLAB_NEVER_MERGE), we can detect if a cache is unmergeable but become
mergeable because the disable_higher_order_debug=1 logic. Those kind of
caches should be keep unmergeable.
diff --git a/mm/slub.c b/mm/slub.c
index 1efbb812..8cbf9f7 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5704,6 +5704,10 @@ static int sysfs_slab_add(struct kmem_cache *s)
return 0;
}
+ if (!unmergeable && disable_higher_order_debug &&
+ (slub_debug & SLAB_NEVER_MERGE))
+ unmergeable = 1;
+
if (unmergeable) {
/*
* Slabcache can never be merged so we can use the name
proper.
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