From: "Huang, Ying" <ying.huang@intel.com>
To: Kairui Song <ryncsn@gmail.com>
Cc: linux-mm@kvack.org, Kairui Song <kasong@tencent.com>,
Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@redhat.com>,
Hugh Dickins <hughd@google.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Matthew Wilcox <willy@infradead.org>,
Michal Hocko <mhocko@suse.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 16/24] mm/swap: reduce scope of get_swap_device in swapin path
Date: Wed, 22 Nov 2023 08:36:36 +0800 [thread overview]
Message-ID: <87sf4yaajv.fsf@yhuang6-desk2.ccr.corp.intel.com> (raw)
In-Reply-To: <20231119194740.94101-17-ryncsn@gmail.com> (Kairui Song's message of "Mon, 20 Nov 2023 03:47:32 +0800")
Kairui Song <ryncsn@gmail.com> writes:
> From: Kairui Song <kasong@tencent.com>
>
> Move get_swap_device into swapin_readahead, simplify the code
> and prepare for follow up commits.
No. Please don't do this. Please check the get/put_swap_device() usage
rule in the comments of get_swap_device().
"
* When we get a swap entry, if there aren't some other ways to
* prevent swapoff, such as the folio in swap cache is locked, page
* table lock is held, etc., the swap entry may become invalid because
* of swapoff. Then, we need to enclose all swap related functions
* with get_swap_device() and put_swap_device(), unless the swap
* functions call get/put_swap_device() by themselves.
"
This is to simplify the reasoning about swapoff and swap entry.
Why does it bother you?
> For the later part in do_swap_page, using swp_swap_info directly is fine
> since in that context, the swap device is pinned by swapcache reference.
[snip]
--
Best Regards,
Huang, Ying
next prev parent reply other threads:[~2023-11-22 0:38 UTC|newest]
Thread overview: 93+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-19 19:47 [PATCH 00/24] Swapin path refactor for optimization and bugfix Kairui Song
2023-11-19 19:47 ` [PATCH 01/24] mm/swap: fix a potential undefined behavior issue Kairui Song
2023-11-19 20:55 ` Matthew Wilcox
2023-11-20 3:35 ` Chris Li
2023-11-20 11:14 ` Kairui Song
2023-11-20 17:34 ` Chris Li
2023-11-19 19:47 ` [PATCH 02/24] mm/swapfile.c: add back some comment Kairui Song
2023-11-19 19:47 ` [PATCH 03/24] mm/swap: move no readahead swapin code to a stand alone helper Kairui Song
2023-11-19 21:00 ` Matthew Wilcox
2023-11-20 11:14 ` Kairui Song
2023-11-20 14:55 ` Dan Carpenter
2023-11-21 5:34 ` Chris Li
2023-11-22 17:33 ` Kairui Song
2023-11-19 19:47 ` [PATCH 04/24] mm/swap: avoid setting page lock bit and doing extra unlock check Kairui Song
2023-11-20 4:17 ` Chris Li
2023-11-20 11:15 ` Kairui Song
2023-11-20 17:44 ` Chris Li
2023-11-22 17:32 ` Kairui Song
2023-11-22 20:57 ` Chris Li
2023-11-24 8:14 ` Kairui Song
2023-11-24 8:37 ` Christopher Li
2023-11-19 19:47 ` [PATCH 05/24] mm/swap: move readahead policy checking into swapin_readahead Kairui Song
2023-11-21 6:15 ` Chris Li
2023-11-21 6:35 ` Kairui Song
2023-11-21 7:41 ` Chris Li
2023-11-21 8:32 ` Kairui Song
2023-11-21 15:24 ` Chris Li
2023-11-19 19:47 ` [PATCH 06/24] swap: rework swapin_no_readahead arguments Kairui Song
2023-11-20 0:20 ` kernel test robot
2023-11-21 6:44 ` Chris Li
2023-11-23 10:51 ` Kairui Song
2023-11-19 19:47 ` [PATCH 07/24] mm/swap: move swap_count to header to be shared Kairui Song
2023-11-21 6:51 ` Chris Li
2023-11-21 7:03 ` Kairui Song
2023-11-19 19:47 ` [PATCH 08/24] mm/swap: check readahead policy per entry Kairui Song
2023-11-20 6:04 ` Huang, Ying
2023-11-20 11:17 ` Kairui Song
2023-11-21 1:10 ` Huang, Ying
2023-11-21 5:20 ` Chris Li
2023-11-21 5:13 ` Chris Li
2023-11-21 7:54 ` Chris Li
2023-11-23 10:52 ` Kairui Song
2023-11-19 19:47 ` [PATCH 09/24] mm/swap: inline __swap_count Kairui Song
2023-11-20 7:41 ` Huang, Ying
2023-11-21 8:02 ` Chris Li
2023-11-19 19:47 ` [PATCH 10/24] mm/swap: remove nr_rotate_swap and related code Kairui Song
2023-11-21 15:45 ` Chris Li
2023-11-19 19:47 ` [PATCH 11/24] mm/swap: also handle swapcache lookup in swapin_readahead Kairui Song
2023-11-20 0:47 ` kernel test robot
2023-11-21 16:06 ` Chris Li
2023-11-24 8:42 ` Kairui Song
2023-11-24 9:10 ` Chris Li
2023-11-19 19:47 ` [PATCH 12/24] mm/swap: simplify arguments for swap_cache_get_folio Kairui Song
2023-11-21 16:36 ` Chris Li
2023-11-19 19:47 ` [PATCH 13/24] swap: simplify swap_cache_get_folio Kairui Song
2023-11-21 16:50 ` Chris Li
2023-11-19 19:47 ` [PATCH 14/24] mm/swap: do shadow lookup as well when doing swap cache lookup Kairui Song
2023-11-21 16:55 ` Chris Li
2023-11-19 19:47 ` [PATCH 15/24] mm/swap: avoid an duplicated swap cache lookup for SYNCHRONOUS_IO device Kairui Song
2023-11-21 17:15 ` Chris Li
2023-11-22 18:08 ` Kairui Song
2023-11-19 19:47 ` [PATCH 16/24] mm/swap: reduce scope of get_swap_device in swapin path Kairui Song
2023-11-19 21:12 ` Matthew Wilcox
2023-11-20 11:14 ` Kairui Song
2023-11-21 17:25 ` Chris Li
2023-11-22 0:36 ` Huang, Ying [this message]
2023-11-23 11:13 ` Kairui Song
2023-11-24 0:40 ` Huang, Ying
2023-11-19 19:47 ` [PATCH 17/24] mm/swap: fix false error when swapoff race with swapin Kairui Song
2023-11-19 19:47 ` [PATCH 18/24] mm/swap: introduce a helper non fault swapin Kairui Song
2023-11-20 1:07 ` kernel test robot
2023-11-22 4:40 ` Chris Li
2023-11-28 11:22 ` Kairui Song
2023-12-13 2:22 ` Chris Li
2023-11-19 19:47 ` [PATCH 19/24] shmem, swap: refactor error check on OOM or race Kairui Song
2023-11-20 7:04 ` Chris Li
2023-11-20 11:17 ` Kairui Song
2023-11-19 19:47 ` [PATCH 20/24] swap: simplify and make swap_find_cache static Kairui Song
2023-11-22 5:01 ` Chris Li
2023-11-19 19:47 ` [PATCH 21/24] swap: make swapin_readahead result checking argument mandatory Kairui Song
2023-11-22 5:15 ` Chris Li
2023-11-24 8:14 ` Kairui Song
2023-11-19 19:47 ` [PATCH 22/24] swap: make swap_cluster_readahead static Kairui Song
2023-11-22 5:20 ` Chris Li
2023-11-19 19:47 ` [PATCH 23/24] swap: fix multiple swap leak when after cgroup migrate Kairui Song
2023-11-20 7:35 ` Huang, Ying
2023-11-20 11:17 ` Kairui Song
2023-11-22 5:34 ` Chris Li
2023-11-19 19:47 ` [PATCH 24/24] mm/swap: change swapin_readahead to swapin_page_fault Kairui Song
2023-11-20 19:09 ` [PATCH 00/24] Swapin path refactor for optimization and bugfix Yosry Ahmed
2023-11-20 20:22 ` Chris Li
2023-11-22 6:46 ` Kairui Song
2023-11-22 6:43 ` Kairui Song
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