From: Yu Zhao <yuzhao@google.com>
To: linux-mm@kvack.org
Cc: Alex Shi <alexs@kernel.org>, Andi Kleen <ak@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Benjamin Manes <ben.manes@gmail.com>,
Dave Chinner <david@fromorbit.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Hillf Danton <hdanton@sina.com>, Jens Axboe <axboe@kernel.dk>,
Johannes Weiner <hannes@cmpxchg.org>,
Jonathan Corbet <corbet@lwn.net>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Matthew Wilcox <willy@infradead.org>,
Mel Gorman <mgorman@suse.de>, Miaohe Lin <linmiaohe@huawei.com>,
Michael Larabel <michael@michaellarabel.com>,
Michal Hocko <mhocko@suse.com>,
Michel Lespinasse <michel@lespinasse.org>,
Rik van Riel <riel@surriel.com>, Roman Gushchin <guro@fb.com>,
Rong Chen <rong.a.chen@intel.com>,
SeongJae Park <sjpark@amazon.de>,
Tim Chen <tim.c.chen@linux.intel.com>,
Vlastimil Babka <vbabka@suse.cz>, Yang Shi <shy828301@gmail.com>,
Ying Huang <ying.huang@intel.com>, Zi Yan <ziy@nvidia.com>,
linux-kernel@vger.kernel.org, lkp@lists.01.org,
page-reclaim@google.com, Yu Zhao <yuzhao@google.com>
Subject: [PATCH v2 01/16] include/linux/memcontrol.h: do not warn in page_memcg_rcu() if !CONFIG_MEMCG
Date: Tue, 13 Apr 2021 00:56:18 -0600 [thread overview]
Message-ID: <20210413065633.2782273-2-yuzhao@google.com> (raw)
In-Reply-To: <20210413065633.2782273-1-yuzhao@google.com>
page_memcg_rcu() warns on !rcu_read_lock_held() regardless of
CONFIG_MEMCG. The following code is legit, but it triggers the warning
when !CONFIG_MEMCG, since lock_page_memcg() and unlock_page_memcg()
are empty for this config.
memcg = lock_page_memcg(page1)
(rcu_read_lock() if CONFIG_MEMCG=y)
do something to page1
if (page_memcg_rcu(page2) == memcg)
do something to page2 too as it cannot be migrated away from the
memcg either.
unlock_page_memcg(page1)
(rcu_read_unlock() if CONFIG_MEMCG=y)
Locking/unlocking rcu consistently for both configs is rigorous but it
also forces unnecessary locking upon users who have no interest in
CONFIG_MEMCG.
This patch removes the assertion for !CONFIG_MEMCG, because
page_memcg_rcu() has a few callers and there are no concerns regarding
their correctness at the moment.
Signed-off-by: Yu Zhao <yuzhao@google.com>
---
include/linux/memcontrol.h | 1 -
1 file changed, 1 deletion(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 0c04d39a7967..f13dc02cf277 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1077,7 +1077,6 @@ static inline struct mem_cgroup *page_memcg(struct page *page)
static inline struct mem_cgroup *page_memcg_rcu(struct page *page)
{
- WARN_ON_ONCE(!rcu_read_lock_held());
return NULL;
}
--
2.31.1.295.g9ea45b61b8-goog
next prev parent reply other threads:[~2021-04-13 6:56 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-13 6:56 [PATCH v2 00/16] Multigenerational LRU Framework Yu Zhao
2021-04-13 6:56 ` Yu Zhao [this message]
2021-04-13 6:56 ` [PATCH v2 02/16] include/linux/nodemask.h: define next_memory_node() if !CONFIG_NUMA Yu Zhao
2021-04-13 6:56 ` [PATCH v2 03/16] include/linux/huge_mm.h: define is_huge_zero_pmd() if !CONFIG_TRANSPARENT_HUGEPAGE Yu Zhao
2021-04-13 6:56 ` [PATCH v2 04/16] include/linux/cgroup.h: export cgroup_mutex Yu Zhao
2021-04-13 6:56 ` [PATCH v2 05/16] mm/swap.c: export activate_page() Yu Zhao
2021-04-13 6:56 ` [PATCH v2 06/16] mm, x86: support the access bit on non-leaf PMD entries Yu Zhao
2021-04-13 6:56 ` [PATCH v2 07/16] mm/vmscan.c: refactor shrink_node() Yu Zhao
2021-04-13 6:56 ` [PATCH v2 08/16] mm: multigenerational lru: groundwork Yu Zhao
2021-04-13 6:56 ` [PATCH v2 09/16] mm: multigenerational lru: activation Yu Zhao
2021-04-13 6:56 ` [PATCH v2 10/16] mm: multigenerational lru: mm_struct list Yu Zhao
2021-04-14 14:36 ` Matthew Wilcox
2021-04-13 6:56 ` [PATCH v2 11/16] mm: multigenerational lru: aging Yu Zhao
2021-04-13 6:56 ` [PATCH v2 12/16] mm: multigenerational lru: eviction Yu Zhao
2021-04-13 6:56 ` [PATCH v2 13/16] mm: multigenerational lru: page reclaim Yu Zhao
2021-04-13 6:56 ` [PATCH v2 14/16] mm: multigenerational lru: user interface Yu Zhao
2021-04-13 6:56 ` [PATCH v2 15/16] mm: multigenerational lru: Kconfig Yu Zhao
2021-04-13 6:56 ` [PATCH v2 16/16] mm: multigenerational lru: documentation Yu Zhao
2021-04-13 7:51 ` [PATCH v2 00/16] Multigenerational LRU Framework SeongJae Park
2021-04-13 16:13 ` Jens Axboe
2021-04-13 16:42 ` SeongJae Park
2021-04-13 23:14 ` Dave Chinner
2021-04-14 2:29 ` Rik van Riel
[not found] ` <CAOUHufafMcaG8sOS=1YMy2P_6p0R1FzP16bCwpUau7g1-PybBQ@mail.gmail.com>
2021-04-14 6:15 ` Huang, Ying
2021-04-14 7:58 ` Yu Zhao
2021-04-14 8:27 ` Huang, Ying
2021-04-14 13:51 ` Rik van Riel
2021-04-14 15:56 ` Andi Kleen
2021-04-14 15:58 ` [page-reclaim] " Shakeel Butt
2021-04-14 18:45 ` Yu Zhao
2021-04-14 15:51 ` Andi Kleen
2021-04-14 15:58 ` Rik van Riel
2021-04-14 19:14 ` Yu Zhao
2021-04-14 19:41 ` Rik van Riel
2021-04-14 20:08 ` Yu Zhao
2021-04-14 19:04 ` Yu Zhao
2021-04-15 3:00 ` Andi Kleen
2021-04-15 7:13 ` Yu Zhao
2021-04-15 8:19 ` Huang, Ying
2021-04-15 9:57 ` Michel Lespinasse
2021-04-24 2:33 ` Yu Zhao
2021-04-24 3:30 ` Andi Kleen
2021-04-24 4:16 ` Yu Zhao
2021-04-14 3:40 ` Yu Zhao
2021-04-14 4:50 ` Dave Chinner
2021-04-14 7:16 ` Yu Zhao
2021-04-14 10:00 ` Yu Zhao
2021-04-15 1:36 ` Dave Chinner
2021-04-24 21:21 ` Yu Zhao
2021-04-14 14:43 ` Jens Axboe
2021-04-14 19:42 ` Yu Zhao
2021-04-15 1:21 ` Dave Chinner
2021-04-14 17:43 ` Johannes Weiner
2021-04-27 10:35 ` Yu Zhao
2021-04-29 23:46 ` Konstantin Kharlamov
2021-04-30 6:37 ` Konstantin Kharlamov
2021-04-30 19:31 ` Yu Zhao
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