From: Miaohe Lin <linmiaohe@huawei.com>
To: <akpm@linux-foundation.org>
Cc: <ying.huang@intel.com>, <dennis@kernel.org>,
<tim.c.chen@linux.intel.com>, <hughd@google.com>,
<hannes@cmpxchg.org>, <mhocko@suse.com>, <iamjoonsoo.kim@lge.com>,
<alexs@kernel.org>, <willy@infradead.org>, <minchan@kernel.org>,
<richard.weiyang@gmail.com>, <shy828301@gmail.com>,
<david@redhat.com>, <linux-kernel@vger.kernel.org>,
<linux-mm@kvack.org>, <linmiaohe@huawei.com>
Subject: [PATCH v5 0/4] close various race windows for swap
Date: Sun, 25 Apr 2021 17:54:15 +0800 [thread overview]
Message-ID: <20210425095419.3830298-1-linmiaohe@huawei.com> (raw)
Hi all,
When I was investigating the swap code, I found some possible race
windows. This series aims to fix all these races. But using current
get/put_swap_device() to guard against concurrent swapoff for
swap_readpage() looks terrible because swap_readpage() may take really
long time. And to reduce the performance overhead on the hot-path as
much as possible, it appears we can use the percpu_ref to close this
race window(as suggested by Huang, Ying). The patch 1 adds percpu_ref
support for swap and most of the remaining patches try to use this to
close various race windows. More details can be found in the respective
changelogs. Thanks!
v4->v5:
collect Reviewed-by tag
do put_swap_device() before returning from the function per Huang, Ying
v3->v4:
some commit log and comment enhance per Huang, Ying
put get/put_swap_device() in shmem_swapin_page() per Huang, Ying
collect Reviewed-by tag
v2->v3:
some commit log and comment enhance per Huang, Ying
remove ref_initialized field
squash PATCH 1-2
v1->v2:
reorganize the patch-2/5
various enhance and fixup per Huang, Ying
Many thanks for the comments of Huang, Ying, Dennis Zhou and Tim Chen.
Miaohe Lin (4):
mm/swapfile: use percpu_ref to serialize against concurrent swapoff
swap: fix do_swap_page() race with swapoff
mm/swap: remove confusing checking for non_swap_entry() in
swap_ra_info()
mm/shmem: fix shmem_swapin() race with swapoff
include/linux/swap.h | 14 ++++++--
mm/memory.c | 11 ++++--
mm/shmem.c | 12 +++++++
mm/swap_state.c | 6 ----
mm/swapfile.c | 79 +++++++++++++++++++++++++++-----------------
5 files changed, 82 insertions(+), 40 deletions(-)
--
2.23.0
next reply other threads:[~2021-04-25 9:54 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-25 9:54 Miaohe Lin [this message]
2021-04-25 9:54 ` [PATCH v5 1/4] mm/swapfile: use percpu_ref to serialize against concurrent swapoff Miaohe Lin
2021-04-25 9:54 ` [PATCH v5 2/4] swap: fix do_swap_page() race with swapoff Miaohe Lin
2021-04-25 9:54 ` [PATCH v5 3/4] mm/swap: remove confusing checking for non_swap_entry() in swap_ra_info() Miaohe Lin
2021-04-25 9:54 ` [PATCH v5 4/4] mm/shmem: fix shmem_swapin() race with swapoff Miaohe Lin
2021-04-26 0:56 ` Huang, Ying
2021-04-26 6:53 ` Yu Zhao
2021-04-26 7:05 ` Miaohe Lin
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