From: Wei Yang <richardw.yang@linux.intel.com>
To: hannes@cmpxchg.org, mhocko@kernel.org, vdavydov.dev@gmail.com,
akpm@linux-foundation.org
Cc: kirill.shutemov@linux.intel.com, cgroups@vger.kernel.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
yang.shi@linux.alibaba.com,
Wei Yang <richardw.yang@linux.intel.com>
Subject: [RFC PATCH] mm: thp: grab the lock before manipulation defer list
Date: Fri, 3 Jan 2020 22:34:07 +0800 [thread overview]
Message-ID: <20200103143407.1089-1-richardw.yang@linux.intel.com> (raw)
As all the other places, we grab the lock before manipulate the defer list.
Current implementation may face a race condition.
Fixes: 87eaceb3faa5 ("mm: thp: make deferred split shrinker memcg aware")
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
---
I notice the difference during code reading and just confused about the
difference. No specific test is done since limited knowledge about cgroup.
Maybe I miss something important?
---
mm/memcontrol.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index bc01423277c5..62b7ec34ef1a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5368,12 +5368,12 @@ static int mem_cgroup_move_account(struct page *page,
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ spin_lock(&from->deferred_split_queue.split_queue_lock);
if (compound && !list_empty(page_deferred_list(page))) {
- spin_lock(&from->deferred_split_queue.split_queue_lock);
list_del_init(page_deferred_list(page));
from->deferred_split_queue.split_queue_len--;
- spin_unlock(&from->deferred_split_queue.split_queue_lock);
}
+ spin_unlock(&from->deferred_split_queue.split_queue_lock);
#endif
/*
* It is safe to change page->mem_cgroup here because the page
@@ -5385,13 +5385,13 @@ static int mem_cgroup_move_account(struct page *page,
page->mem_cgroup = to;
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ spin_lock(&to->deferred_split_queue.split_queue_lock);
if (compound && list_empty(page_deferred_list(page))) {
- spin_lock(&to->deferred_split_queue.split_queue_lock);
list_add_tail(page_deferred_list(page),
&to->deferred_split_queue.split_queue);
to->deferred_split_queue.split_queue_len++;
- spin_unlock(&to->deferred_split_queue.split_queue_lock);
}
+ spin_unlock(&to->deferred_split_queue.split_queue_lock);
#endif
spin_unlock_irqrestore(&from->move_lock, flags);
--
2.17.1
next reply other threads:[~2020-01-03 14:34 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-03 14:34 Wei Yang [this message]
2020-01-03 19:29 ` David Rientjes
2020-01-03 23:39 ` Wei Yang
2020-01-04 0:44 ` David Rientjes
2020-01-06 1:20 ` Wei Yang
2020-01-06 10:23 ` Michal Hocko
2020-01-07 1:22 ` Wei Yang
2020-01-07 8:38 ` Michal Hocko
2020-01-08 0:35 ` Wei Yang
2020-01-08 9:40 ` Michal Hocko
2020-01-09 2:03 ` Wei Yang
2020-01-09 8:34 ` Michal Hocko
2020-01-09 3:18 ` Wei Yang
2020-01-09 8:36 ` Michal Hocko
2020-01-09 8:52 ` Wei Yang
2020-01-06 16:18 ` Alexander Duyck
2020-01-07 1:26 ` Wei Yang
2020-01-07 2:07 ` David Rientjes
2020-01-07 2:33 ` Wei Yang
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