linux-kernel - Re: [PATCH v3] zram: don't free statically defined names

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Message-ID: <CAF8kJuNDzk21jZR1+TkGdMOrXdQcfa+=bxLF6FhyuXzRwT4Y9Q@mail.gmail.com>
Date: Tue, 24 Sep 2024 21:04:10 -0700
From: Chris Li <chrisl@...nel.org>
To: Sergey Senozhatsky <senozhatsky@...omium.org>
Cc: Venkat Rao Bagalkote <venkat88@...ux.vnet.ibm.com>, Andrew Morton <akpm@...ux-foundation.org>, 
	Andrey Skvortsov <andrej.skvortzov@...il.com>, Minchan Kim <minchan@...nel.org>, 
	Jens Axboe <axboe@...nel.dk>, linux-kernel@...r.kernel.org, linux-block@...r.kernel.org, 
	stable@...r.kernel.org, Sachin Sant <sachinp@...ux.ibm.com>, 
	linux-mm <linux-mm@...ck.org>
Subject: Re: [PATCH v3] zram: don't free statically defined names

On Tue, Sep 24, 2024 at 5:37 PM Sergey Senozhatsky
<senozhatsky@...omium.org> wrote:
>
> On (24/09/24 11:29), Chris Li wrote:
> > On Tue, Sep 24, 2024 at 8:56 AM Chris Li <chrisl@...nel.org> wrote:
> [..]
> > Given the merge window is closing. I suggest just reverting this
> > change. As it is the fix also causing regression in the swap stress
> > test for me. It is possible that is my test setup issue, but reverting
> > sounds the safe bet.
>
> The patch in question is just a kfree() call that is only executed
> during zram reset and that fixes tiny memory leaks when zram is
> configured with alternative (re-compression) streams.  I cannot
> imagine how that can have any impact on runtime, that makes no
> sense to me, I'm not sure that revert is justified here.
>
After some discussion with Sergey, we have more progress on
understanding the swap stress test regression.
One of the triggering conditions is I don't have zram lz4 config
enabled, (the config option name has changed) and the test script
tries to set lz4 on zram and fails. It will fall back to the lzo.
Anyway, if I have zram lz4 configured, my stress test can pass with
the fix. Still I don't understand why disabling lz4 config can trigger
it. Need to dig more.

Agree that we don't need to revert this.

Chris