| From | Alex Shi <> | Subject | [PATCH v18 12/32] mm/memcg: optimize mem_cgroup_page_lruvec | Date | Mon, 24 Aug 2020 20:54:45 +0800 |
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From: Hugh Dickins <hughd@google.com>
Add READ_ONCE on page->mem_cgroup, since we will check it later. Also the page should not be PageTail(page), so add a check.
Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Cc: cgroups@vger.kernel.org --- mm/memcontrol.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 505f54087e82..65c1e873153e 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1321,7 +1321,8 @@ struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgd goto out; } - memcg = page->mem_cgroup; + VM_BUG_ON_PAGE(PageTail(page), page); + memcg = READ_ONCE(page->mem_cgroup); /* Readahead page is charged too, to see if other page uncharged */ VM_WARN_ON_ONCE_PAGE(!memcg, page); if (!memcg) -- 1.8.3.1
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