From: Martin Doucha <mdoucha@suse.cz>
To: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>, Petr Vorel <pvorel@suse.cz>,
ltp@lists.linux.it, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
Nitin Gupta <ngupta@vflare.org>, Jens Axboe <axboe@kernel.dk>,
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>,
Yang Xu <xuyang2018.jy@fujitsu.com>
Subject: Re: [PATCH 0/1] Possible bug in zram on ppc64le on vfat
Date: Tue, 22 Nov 2022 15:56:25 +0100 [thread overview]
Message-ID: <9489dd1c-012c-8b5d-b670-a27213da287a@suse.cz> (raw)
In-Reply-To: <Y22b3wWs2QfMjJHi@google.com>
On 11. 11. 22 1:48, Sergey Senozhatsky wrote:
> On (22/11/10 15:29), Martin Doucha wrote:
>> I've tried to debug the issue and collected some interesting data (all
>> values come from zram device with 25M size limit and zstd compression
>> algorithm):
>> - mm_stat values are correct after mkfs.vfat:
>> 65536 220 65536 26214400 65536 0 0 0
>>
>> - mm_stat values stay correct after mount:
>> 65536 220 65536 26214400 65536 0 0 0
>>
>> - the bug is triggered by filling the filesystem to capacity (using dd):
>> 4194304 0 0 26214400 327680 64 0 0
>
> Can you try using /dev/urandom for dd, not /dev/zero?
> Do you still see zeroes in sysfs output or some random values?
After 50 test runs on a kernel where the issue is confirmed, I could not
reproduce the failure while filling the device from /dev/urandom instead
of /dev/zero. The test reported compression ratio around 1.8-2.5 which
means the memory usage reported by mm_stat was 10-13MB.
Note that I had to disable the other filesystems in the test because
some of them kept failing with compression ratio <1.
--
Martin Doucha mdoucha@suse.cz
QA Engineer for Software Maintenance
SUSE LINUX, s.r.o.
CORSO IIa
Krizikova 148/34
186 00 Prague 8
Czech Republic
next prev parent reply other threads:[~2022-11-22 14:59 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-07 19:11 [PATCH 0/1] Possible bug in zram on ppc64le on vfat Petr Vorel
2022-11-07 19:11 ` [PATCH 1/1] zram01.sh: Workaround division by 0 on vfat on ppc64le Petr Vorel
[not found] ` <CAEemH2fYv_=9UWdWB7VDiFOd8EC89qdCbxnPcTPAtGnkwLOYFg@mail.gmail.com>
2022-11-21 8:59 ` [LTP] " Petr Vorel
2022-11-07 21:25 ` [PATCH 0/1] Possible bug in zram on ppc64le on vfat Minchan Kim
2022-11-07 21:47 ` Petr Vorel
2022-11-07 22:42 ` Petr Vorel
2022-11-08 1:05 ` Sergey Senozhatsky
2022-11-09 22:08 ` Petr Vorel
2022-11-10 23:04 ` Minchan Kim
2022-11-11 9:29 ` Petr Vorel
2022-11-10 14:29 ` Martin Doucha
2022-11-11 0:48 ` Sergey Senozhatsky
2022-11-21 9:41 ` Petr Vorel
2022-11-22 14:56 ` Martin Doucha [this message]
2022-11-22 15:07 ` Petr Vorel
2022-11-29 4:38 ` Sergey Senozhatsky
2023-05-02 15:23 ` Martin Doucha
2022-11-11 9:18 ` Petr Vorel
2023-08-04 6:37 ` Ian Wienand
2023-08-07 4:44 ` Ian Wienand
2023-08-07 5:19 ` Sergey Senozhatsky
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