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From: Yosry Ahmed <yosryahmed@google.com>
To: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Yu Zhao <yuzhao@google.com>, Minchan Kim <minchan@kernel.org>,
	 Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org,  linux-mm@kvack.org
Subject: Re: [PATCHv4 0/4] zsmalloc: fine-grained fullness and new compaction algorithm
Date: Mon, 17 Apr 2023 04:31:11 -0700	[thread overview]
Message-ID: <CAJD7tkbC5drsA2s+=sxXGGm+2RAFXbqs_21KrGaWav_LKjA68w@mail.gmail.com> (raw)
In-Reply-To: <20230417112421.GO25053@google.com>

On Mon, Apr 17, 2023 at 4:24 AM Sergey Senozhatsky
<senozhatsky@chromium.org> wrote:
>
> On (23/04/17 04:16), Yosry Ahmed wrote:
> > > That's a good question to which I don't have an answer. We can list_add()
> > > the same zspage twice, unlocking the pool after first list_add() so that
> > > another process (including another zs_compact()) can do something to that
> > > zspage. The answer is somewhere between these lines, I guess.
> >
> > But the first list_add() is (in this case) the correct add, so we
> > expect other processes to be able to access the zspage after the first
> > list_add() anyway, right?
>
> Correct. Compaction also can unlock pool->lock and schedule() so that
> another process can access the source zspage, when compaction gets
> scheduled it can attempt putback/unlock the same zspage one more time
> (the zspage may not even exist at this point, I assume).

Good point, that could very well be where the corruption is coming
from. Thanks for pointing this out.


      reply	other threads:[~2023-04-17 11:31 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-04  3:48 Sergey Senozhatsky
2023-03-04  3:48 ` [PATCHv4 1/4] zsmalloc: remove insert_zspage() ->inuse optimization Sergey Senozhatsky
2023-03-04  3:48 ` [PATCHv4 2/4] zsmalloc: fine-grained inuse ratio based fullness grouping Sergey Senozhatsky
2023-03-04  3:48 ` [PATCHv4 3/4] zsmalloc: rework compaction algorithm Sergey Senozhatsky
2023-04-17  5:01   ` [PATCH] zsmalloc: reset compaction source zspage pointer after putback_zspage() Sergey Senozhatsky
2023-04-17  5:11     ` Yu Zhao
2023-04-17 11:43     ` Yosry Ahmed
2023-04-17 13:07       ` Sergey Senozhatsky
2023-04-17 13:08   ` Sergey Senozhatsky
2023-03-04  3:48 ` [PATCHv4 4/4] zsmalloc: show per fullness group class stats Sergey Senozhatsky
2023-03-10 21:10 ` [PATCHv4 0/4] zsmalloc: fine-grained fullness and new compaction algorithm Minchan Kim
2023-03-11  8:30   ` Sergey Senozhatsky
2023-04-16  7:20 ` Yu Zhao
2023-04-16 15:18   ` Sergey Senozhatsky
2023-04-16 19:27     ` Yu Zhao
2023-04-17  2:44       ` Sergey Senozhatsky
2023-04-17  2:55         ` Yu Zhao
2023-04-17  3:52           ` Sergey Senozhatsky
2023-04-17  8:29             ` Yosry Ahmed
2023-04-17 11:12               ` Sergey Senozhatsky
2023-04-17 11:16                 ` Yosry Ahmed
2023-04-17 11:24                   ` Sergey Senozhatsky
2023-04-17 11:31                     ` Yosry Ahmed [this message]

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