On 5/5/21 10:06 PM, Waiman Long wrote: > The KMALLOC_NORMAL (kmalloc-<n>) caches are for unaccounted objects only > when CONFIG_MEMCG_KMEM is enabled. To make sure that this condition > remains true, we will have to prevent KMALOC_NORMAL caches to merge > with other kmem caches. This is now done by setting its refcount to -1 > right after its creation. > > Suggested-by: Roman Gushchin <guro@xxxxxx> > Signed-off-by: Waiman Long <longman@xxxxxxxxxx> Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx> (outside of scope of this patch/series, we should later replace this refcount ugliness with a proper slab flag) > --- > mm/slab_common.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/mm/slab_common.c b/mm/slab_common.c > index bbaf41a7c77e..a0ff8e1d8b67 100644 > --- a/mm/slab_common.c > +++ b/mm/slab_common.c > @@ -841,6 +841,13 @@ new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags) > kmalloc_info[idx].name[type], > kmalloc_info[idx].size, flags, 0, > kmalloc_info[idx].size); > + > + /* > + * If CONFIG_MEMCG_KMEM is enabled, disable cache merging for > + * KMALLOC_NORMAL caches. > + */ > + if (IS_ENABLED(CONFIG_MEMCG_KMEM) && (type == KMALLOC_NORMAL)) > + kmalloc_caches[type][idx]->refcount = -1; > } > > /* >
