On 08/27/14 at 10:32am, Christoph Lameter wrote:
> Maybe something like this may be a proper fix:
>
> Subject: slub: Disable tracing of mergeable slabs
>
> Tracing of mergeable slabs is confusing since the objects
> of multiple slab caches will be traced. Moreover this creates
> a situation where a mergeable slab will become unmergeable.
>
> If tracing is desired then it may be best to switch merging
> off for starters.
>
> Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>
>
> Index: linux/mm/slub.c
> ===================================================================
> --- linux.orig/mm/slub.c 2014-08-08 11:52:30.039681592 -0500
> +++ linux/mm/slub.c 2014-08-27 10:30:16.508108726 -0500
> @@ -4604,6 +4604,14 @@ static ssize_t trace_show(struct kmem_ca
> static ssize_t trace_store(struct kmem_cache *s, const char *buf,
> size_t length)
> {
> + /*
> + * Tracing a merged cache is going to give confusing results
> + * as well as cause other issues like converting a mergeable
> + * cache into an umergeable one.
> + */
> + if (s->refcount > 1)
> + return -EINVAL;
> +
> s->flags &= ~SLAB_TRACE;
> if (buf[0] == '1') {
> s->flags &= ~__CMPXCHG_DOUBLE;
What about failslab_store()? SLAB_FAILSLAB is also a nomerge flag.
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