On Tue, Jun 19, 2018 at 2:33 PM Shakeel Butt <[email protected]> wrote: > > For !CONFIG_SLUB_DEBUG, SLUB does not maintain the number of slabs > allocated per node for a kmem_cache. Thus, slabs_node() in > __kmem_cache_empty() will always return 0. So, in such situation, it is > required to check per-cpu slabs to make sure if a kmem_cache is empty or > not. > > Please note that __kmem_cache_shutdown() and __kmem_cache_shrink() are > not affected by !CONFIG_SLUB_DEBUG as they call flush_all() to clear > per-cpu slabs. > > Fixes: f9e13c0a5a33 ("slab, slub: skip unnecessary kasan_cache_shutdown()") > Signed-off-by: Shakeel Butt <[email protected]> > Reported-by: Jason A . Donenfeld <[email protected]> > Cc: Christoph Lameter <[email protected]> > Cc: Pekka Enberg <[email protected]> > Cc: David Rientjes <[email protected]> > Cc: Joonsoo Kim <[email protected]> > Cc: Andrew Morton <[email protected]> > Cc: <[email protected]>
Forgot to Cc: Andrey Ryabinin <[email protected]> > --- > mm/slub.c | 16 +++++++++++++++- > 1 file changed, 15 insertions(+), 1 deletion(-) > > diff --git a/mm/slub.c b/mm/slub.c > index a3b8467c14af..731c02b371ae 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -3673,9 +3673,23 @@ static void free_partial(struct kmem_cache *s, struct > kmem_cache_node *n) > > bool __kmem_cache_empty(struct kmem_cache *s) > { > - int node; > + int cpu, node; > struct kmem_cache_node *n; > > + /* > + * slabs_node will always be 0 for !CONFIG_SLUB_DEBUG. So, manually > + * check slabs for all cpus. > + */ > + if (!IS_ENABLED(CONFIG_SLUB_DEBUG)) { > + for_each_online_cpu(cpu) { > + struct kmem_cache_cpu *c; > + > + c = per_cpu_ptr(s->cpu_slab, cpu); > + if (c->page || slub_percpu_partial(c)) > + return false; > + } > + } > + > for_each_kmem_cache_node(s, node, n) > if (n->nr_partial || slabs_node(s, node)) > return false; > -- > 2.18.0.rc1.244.gcf134e6275-goog >
