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From: Miaohe Lin <linmiaohe@huawei.com>
To: "Huang, Ying" <ying.huang@intel.com>,
	Tim Chen <tim.c.chen@linux.intel.com>
Cc: <akpm@linux-foundation.org>, <hannes@cmpxchg.org>,
	<mhocko@suse.com>, <iamjoonsoo.kim@lge.com>, <vbabka@suse.cz>,
	<alex.shi@linux.alibaba.com>, <willy@infradead.org>,
	<minchan@kernel.org>, <richard.weiyang@gmail.com>,
	<hughd@google.com>, <linux-kernel@vger.kernel.org>,
	<linux-mm@kvack.org>
Subject: Re: [PATCH 2/5] swap: fix do_swap_page() race with swapoff
Date: Wed, 14 Apr 2021 10:20:37 +0800	[thread overview]
Message-ID: <26c15777-d775-967b-3ddf-1db983154053@huawei.com> (raw)
In-Reply-To: <878s5lu16i.fsf@yhuang6-desk1.ccr.corp.intel.com>

On 2021/4/14 9:04, Huang, Ying wrote:
> Tim Chen <tim.c.chen@linux.intel.com> writes:
> 
>> On 4/12/21 6:27 PM, Huang, Ying wrote:
>>
>>>
>>> This isn't the commit that introduces the race.  You can use `git blame`
>>> find out the correct commit.  For this it's commit 0bcac06f27d7 "mm,
>>> swap: skip swapcache for swapin of synchronous device".
>>>
>>> And I suggest to merge 1/5 and 2/5 to make it easy to get the full
>>> picture.
>>
>> I'll suggest make fix to do_swap_page race with get/put_swap_device
>> as a first patch. Then the per_cpu_ref stuff in patch 1 and patch 2 can
>> be combined together.
> 
> The original get/put_swap_device() use rcu_read_lock/unlock().  I don't
> think it's good to wrap swap_read_page() with it.  After all, some
> complex operations are done in swap_read_page(), including
> blk_io_schedule().
> 

The patch was split to make it easier to review originally, i.e. 1/5 introduces
the percpu_ref to swap and 2/5 uses it to fix the race between do_swap_page()
and swapoff.
Btw, I have no preference for merging 1/5 and 2/5 or not.

> Best Regards,
> Huang, Ying
> .
> 



  reply	other threads:[~2021-04-14  2:20 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-08 13:08 [PATCH 0/5] close various race windows for swap Miaohe Lin
2021-04-08 13:08 ` [PATCH 3/5] mm/swap_state: fix get_shadow_from_swap_cache() race with swapoff Miaohe Lin
2021-04-13  1:33   ` Huang, Ying
2021-04-14  2:42     ` Miaohe Lin
2021-04-08 13:08 ` [PATCH 4/5] mm/swap_state: fix potential faulted in race in swap_ra_info() Miaohe Lin
2021-04-09  8:50   ` Huang, Ying
2021-04-09  9:00     ` Miaohe Lin
2021-04-12  0:55       ` Huang, Ying
2021-04-12  3:17         ` Miaohe Lin
2021-04-08 13:08 ` [PATCH 5/5] mm/swap_state: fix swap_cluster_readahead() race with swapoff Miaohe Lin
2021-04-13  1:36   ` Huang, Ying
2021-04-14  2:43     ` Miaohe Lin
2021-04-08 14:55 ` [PATCH 0/5] close various race windows for swap riteshh
2021-04-09  8:01   ` Miaohe Lin
     [not found] ` <20210408130820.48233-2-linmiaohe@huawei.com>
2021-04-12  3:30   ` [PATCH 1/5] mm/swapfile: add percpu_ref support " Huang, Ying
2021-04-12  6:59     ` Miaohe Lin
2021-04-12  7:24     ` Huang, Ying
2021-04-13 12:39       ` Miaohe Lin
2021-04-14  1:17         ` Huang, Ying
2021-04-14  1:58           ` Miaohe Lin
2021-04-14  2:06             ` Huang, Ying
2021-04-14  3:44               ` Dennis Zhou
2021-04-14  3:59                 ` Huang, Ying
2021-04-14  4:05                   ` Dennis Zhou
2021-04-14  5:44                     ` Huang, Ying
2021-04-14 14:53                       ` Dennis Zhou
2021-04-15  3:16                         ` Miaohe Lin
2021-04-15  4:20                           ` Dennis Zhou
2021-04-15  9:17                             ` Miaohe Lin
2021-04-15  5:24                         ` Huang, Ying
2021-04-15 14:31                           ` Dennis Zhou
2021-04-16  0:54                             ` Huang, Ying
2021-04-16  2:27                             ` Miaohe Lin
2021-04-16  6:25                               ` Huang, Ying
2021-04-16  8:30                                 ` Miaohe Lin
     [not found] ` <20210408130820.48233-3-linmiaohe@huawei.com>
2021-04-08 21:34   ` [PATCH 2/5] swap: fix do_swap_page() race with swapoff Tim Chen
2021-04-09  8:42     ` Miaohe Lin
2021-04-09 17:17       ` Tim Chen
2021-04-10  3:17         ` Miaohe Lin
2021-04-12  1:44           ` Huang, Ying
2021-04-12  3:24             ` Miaohe Lin
2021-04-13  1:27   ` Huang, Ying
2021-04-13 19:24     ` Tim Chen
2021-04-14  1:04       ` Huang, Ying
2021-04-14  2:20         ` Miaohe Lin [this message]
2021-04-14 16:13         ` Tim Chen
2021-04-15  3:19           ` Miaohe Lin
2021-04-14  2:55     ` Miaohe Lin
2021-04-14  3:07       ` Huang, Ying
2021-04-14  3:27         ` Miaohe Lin

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