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authorRoman Gushchin <guro@fb.com>2020-03-28 19:17:25 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-03-29 09:47:05 -0700
commit8380ce479010f2f779587b462a9b4681934297c3 (patch)
treeec74864739f3bff28b926c2ab79477ccb6389152 /include
parent726b7bbeafd4e0219c37b74673d368b21ff3d039 (diff)
downloadlinux-8380ce479010f2f779587b462a9b4681934297c3.tar.bz2
mm: fork: fix kernel_stack memcg stats for various stack implementations
Depending on CONFIG_VMAP_STACK and the THREAD_SIZE / PAGE_SIZE ratio the space for task stacks can be allocated using __vmalloc_node_range(), alloc_pages_node() and kmem_cache_alloc_node(). In the first and the second cases page->mem_cgroup pointer is set, but in the third it's not: memcg membership of a slab page should be determined using the memcg_from_slab_page() function, which looks at page->slab_cache->memcg_params.memcg . In this case, using mod_memcg_page_state() (as in account_kernel_stack()) is incorrect: page->mem_cgroup pointer is NULL even for pages charged to a non-root memory cgroup. It can lead to kernel_stack per-memcg counters permanently showing 0 on some architectures (depending on the configuration). In order to fix it, let's introduce a mod_memcg_obj_state() helper, which takes a pointer to a kernel object as a first argument, uses mem_cgroup_from_obj() to get a RCU-protected memcg pointer and calls mod_memcg_state(). It allows to handle all possible configurations (CONFIG_VMAP_STACK and various THREAD_SIZE/PAGE_SIZE values) without spilling any memcg/kmem specifics into fork.c . Note: This is a special version of the patch created for stable backports. It contains code from the following two patches: - mm: memcg/slab: introduce mem_cgroup_from_obj() - mm: fork: fix kernel_stack memcg stats for various stack implementations [guro@fb.com: introduce mem_cgroup_from_obj()] Link: http://lkml.kernel.org/r/20200324004221.GA36662@carbon.dhcp.thefacebook.com Fixes: 4d96ba353075 ("mm: memcg/slab: stop setting page->mem_cgroup pointer for slab pages") Signed-off-by: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Bharata B Rao <bharata@linux.ibm.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20200303233550.251375-1-guro@fb.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/memcontrol.h12
1 files changed, 12 insertions, 0 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index a7a0a1a5c8d5..e9ba01336d4e 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -695,6 +695,7 @@ static inline unsigned long lruvec_page_state_local(struct lruvec *lruvec,
void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
int val);
void __mod_lruvec_slab_state(void *p, enum node_stat_item idx, int val);
+void mod_memcg_obj_state(void *p, int idx, int val);
static inline void mod_lruvec_state(struct lruvec *lruvec,
enum node_stat_item idx, int val)
@@ -1123,6 +1124,10 @@ static inline void __mod_lruvec_slab_state(void *p, enum node_stat_item idx,
__mod_node_page_state(page_pgdat(page), idx, val);
}
+static inline void mod_memcg_obj_state(void *p, int idx, int val)
+{
+}
+
static inline
unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
gfp_t gfp_mask,
@@ -1427,6 +1432,8 @@ static inline int memcg_cache_id(struct mem_cgroup *memcg)
return memcg ? memcg->kmemcg_id : -1;
}
+struct mem_cgroup *mem_cgroup_from_obj(void *p);
+
#else
static inline int memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
@@ -1468,6 +1475,11 @@ static inline void memcg_put_cache_ids(void)
{
}
+static inline struct mem_cgroup *mem_cgroup_from_obj(void *p)
+{
+ return NULL;
+}
+
#endif /* CONFIG_MEMCG_KMEM */
#endif /* _LINUX_MEMCONTROL_H */