linux-kernel - Re: FUSE: write operations trigger balance_dirty

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAJfpegtOqbhwKBpaGdWwcBG5sBrbjtLFzpFsqsB8_VbT7=vE9w@mail.gmail.com>
Date:   Thu, 9 Aug 2018 09:14:28 +0200
From:   Miklos Szeredi <miklos@...redi.hu>
To:     刘硕然 <liushuoran@...com>
Cc:     "linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: FUSE: write operations trigger balance_dirty_pages when using
 writeback cache

On Thu, Aug 9, 2018 at 5:37 AM, 刘硕然 <liushuoran@...com> wrote:
> Dear Miklos,
>
> Recently I've been testing FUSE and libfuse example passthrough_ll with writeback cache on, and found out that the performance drops significantly compared to that in local filesystem. As I can see from trace, balance_dirty_pages is triggered very frequently even if there not enough pages that shall be sent to libfuse. I'm not sure if this is a known fact or the FUSE writeback feature requires some specific configurations. Trace log is attached.
>
> dd-19067 [001] .... 195295.568097: balance_dirty_pages: bdi 0:42: limit=3180390 setpoint=2782421 dirty=5 bdi_setpoint=0 bdi_dirty=32 dirty_ratelimit=32 task_ratelimit=0 dirtied=32 dirtied_pause=32 paused=0 pause=33 period=33 think=0 cgroup_ino=1
> dd-19067 [001] .... 195295.602029: balance_dirty_pages: bdi 0:42: limit=3180390 setpoint=2782421 dirty=5 bdi_setpoint=0 bdi_dirty=33 dirty_ratelimit=32 task_ratelimit=0 dirtied=1 dirtied_pause=0 paused=0 pause=34 period=34 think=1 cgroup_ino=1
> dd-19067 [001] .... 195295.637026: balance_dirty_pages: bdi 0:42: limit=3180390 setpoint=2782421 dirty=5 bdi_setpoint=0 bdi_dirty=34 dirty_ratelimit=32 task_ratelimit=0 dirtied=1 dirtied_pause=0 paused=0 pause=35 period=35 think=1 cgroup_ino=1
>
> BTW, I'm using Linux kernel 4.17.12 and libfuse 3.2.5. Look forward to hearing from you. Thanks in advance.

Try

   echo 20 > /sys/devices/virtual/bdi/0:`stat -c %d /mnt/fuse/`/max_ratio

where you replace /mnt/fuse with your mountpoint.

Thanks,
Miklos