| Message ID | 20210505200610.13943-4-longman@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm: memcg/slab: Fix objcg pointer array handling problem | expand |
On Wed, May 05, 2021 at 04:06:10PM -0400, 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@fb.com> > Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Roman Gushchin <guro@fb.com>
On Wed, May 5, 2021 at 1:06 PM Waiman Long <longman@redhat.com> 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@fb.com> > Signed-off-by: Waiman Long <longman@redhat.com> Reviewed-by: Shakeel Butt <shakeelb@google.com>
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@fb.com> > Signed-off-by: Waiman Long <longman@redhat.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> (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; > } > > /* >
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; } /*
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@fb.com> Signed-off-by: Waiman Long <longman@redhat.com> --- mm/slab_common.c | 7 +++++++ 1 file changed, 7 insertions(+)