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mm: workingset: fix vmstat counters for shadow nodes

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Memcg counters for shadow nodes are broken because the memcg pointer is
obtained in a wrong way. The following approach is used:
        virt_to_page(xa_node)->mem_cgroup

Since commit 4d96ba3530 ("mm: memcg/slab: stop setting
page->mem_cgroup pointer for slab pages") page->mem_cgroup pointer isn't
set for slab pages, so memcg_from_slab_page() should be used instead.

Also I doubt that it ever worked correctly: virt_to_head_page() should
be used instead of virt_to_page().  Otherwise objects residing on tail
pages are not accounted, because only the head page contains a valid
mem_cgroup pointer.  That was a case since the introduction of these
counters by the commit 68d48e6a2d ("mm: workingset: add vmstat counter
for shadow nodes").

Link: http://lkml.kernel.org/r/20190801233532.138743-1-guro@fb.com
Fixes: 4d96ba3530 ("mm: memcg/slab: stop setting page->mem_cgroup pointer for slab pages")
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Roman Gushchin
2019-08-13 15:37:41 -07:00
committed by Linus Torvalds
parent 951531691c
commit ec9f02384f
3 changed files with 43 additions and 6 deletions
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10
mm/workingset.c
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@@ -380,14 +380,12 @@ void workingset_update_node(struct xa_node *node)
if (node->count && node->count == node->nr_values) {
if (list_empty(&node->private_list)) {
list_lru_add(&shadow_nodes, &node->private_list);
__inc_lruvec_page_state(virt_to_page(node),
WORKINGSET_NODES);
__inc_lruvec_slab_state(node, WORKINGSET_NODES);
}
} else {
if (!list_empty(&node->private_list)) {
list_lru_del(&shadow_nodes, &node->private_list);
__dec_lruvec_page_state(virt_to_page(node),
WORKINGSET_NODES);
__dec_lruvec_slab_state(node, WORKINGSET_NODES);
}
}
}
@@ -480,7 +478,7 @@ static enum lru_status shadow_lru_isolate(struct list_head *item,
}
list_lru_isolate(lru, item);
__dec_lruvec_page_state(virt_to_page(node), WORKINGSET_NODES);
__dec_lruvec_slab_state(node, WORKINGSET_NODES);
spin_unlock(lru_lock);
@@ -503,7 +501,7 @@ static enum lru_status shadow_lru_isolate(struct list_head *item,
* shadow entries we were tracking ...
*/
xas_store(&xas, NULL);
__inc_lruvec_page_state(virt_to_page(node), WORKINGSET_NODERECLAIM);
__inc_lruvec_slab_state(node, WORKINGSET_NODERECLAIM);
out_invalid:
xa_unlock_irq(&mapping->i_pages);