| Message ID | 20211001190938.14050-3-longman@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm, memcg: Miscellaneous cleanups | expand |
On Fri, Oct 01, 2021 at 03:09:37PM -0400, Waiman Long wrote: > Since commit d648bcc7fe65 ("mm: kmem: make memcg_kmem_enabled() > irreversible"), the only thing memcg_free_kmem() does is to call > memcg_offline_kmem() when the memcg is still online. However, > memcg_offline_kmem() is only called from mem_cgroup_css_free() which > cannot be reached if the memcg hasn't been offlined first. Hm, is it true? What if online_css() fails? > As this > function now serves no purpose, we should just remove it. It looks like we can just use memcg_offline_kmem() instead of memcg_free_kmem(). Thanks! > > Signed-off-by: Waiman Long <longman@redhat.com> > --- > mm/memcontrol.c | 11 ----------- > 1 file changed, 11 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 4568363062c1..8177f253a127 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -3673,13 +3673,6 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg) > > memcg_free_cache_id(kmemcg_id); > } > - > -static void memcg_free_kmem(struct mem_cgroup *memcg) > -{ > - /* css_alloc() failed, offlining didn't happen */ > - if (unlikely(memcg->kmem_state == KMEM_ONLINE)) > - memcg_offline_kmem(memcg); > -} > #else > static int memcg_online_kmem(struct mem_cgroup *memcg) > { > @@ -3688,9 +3681,6 @@ static int memcg_online_kmem(struct mem_cgroup *memcg) > static void memcg_offline_kmem(struct mem_cgroup *memcg) > { > } > -static void memcg_free_kmem(struct mem_cgroup *memcg) > -{ > -} > #endif /* CONFIG_MEMCG_KMEM */ > > static int memcg_update_kmem_max(struct mem_cgroup *memcg, > @@ -5325,7 +5315,6 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css) > cancel_work_sync(&memcg->high_work); > mem_cgroup_remove_from_trees(memcg); > free_shrinker_info(memcg); > - memcg_free_kmem(memcg); > mem_cgroup_free(memcg); > } > > -- > 2.18.1 >
On 10/1/21 8:01 PM, Roman Gushchin wrote: > On Fri, Oct 01, 2021 at 03:09:37PM -0400, Waiman Long wrote: >> Since commit d648bcc7fe65 ("mm: kmem: make memcg_kmem_enabled() >> irreversible"), the only thing memcg_free_kmem() does is to call >> memcg_offline_kmem() when the memcg is still online. However, >> memcg_offline_kmem() is only called from mem_cgroup_css_free() which >> cannot be reached if the memcg hasn't been offlined first. > Hm, is it true? What if online_css() fails? I just realize that memcg_online_kmem() is called at css_create(). So yes, if css_online() fails (i.e. ENOMEM), we will need to do memcg_offline_kmem(). >> As this >> function now serves no purpose, we should just remove it. > It looks like we can just use memcg_offline_kmem() instead of > memcg_free_kmem(). Right, memcg_free_kmem() isn't the right name for that. I agree that we should just change mem_cgroup_css_free() to call memcg_offline_kmem() directly. Will update the patch accordingly. Thanks, Longman
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 4568363062c1..8177f253a127 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3673,13 +3673,6 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg) memcg_free_cache_id(kmemcg_id); } - -static void memcg_free_kmem(struct mem_cgroup *memcg) -{ - /* css_alloc() failed, offlining didn't happen */ - if (unlikely(memcg->kmem_state == KMEM_ONLINE)) - memcg_offline_kmem(memcg); -} #else static int memcg_online_kmem(struct mem_cgroup *memcg) { @@ -3688,9 +3681,6 @@ static int memcg_online_kmem(struct mem_cgroup *memcg) static void memcg_offline_kmem(struct mem_cgroup *memcg) { } -static void memcg_free_kmem(struct mem_cgroup *memcg) -{ -} #endif /* CONFIG_MEMCG_KMEM */ static int memcg_update_kmem_max(struct mem_cgroup *memcg, @@ -5325,7 +5315,6 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css) cancel_work_sync(&memcg->high_work); mem_cgroup_remove_from_trees(memcg); free_shrinker_info(memcg); - memcg_free_kmem(memcg); mem_cgroup_free(memcg); }
Since commit d648bcc7fe65 ("mm: kmem: make memcg_kmem_enabled() irreversible"), the only thing memcg_free_kmem() does is to call memcg_offline_kmem() when the memcg is still online. However, memcg_offline_kmem() is only called from mem_cgroup_css_free() which cannot be reached if the memcg hasn't been offlined first. As this function now serves no purpose, we should just remove it. Signed-off-by: Waiman Long <longman@redhat.com> --- mm/memcontrol.c | 11 ----------- 1 file changed, 11 deletions(-)