linux-kernel - Re: [PATCH] mm/page-writeback: Raise wb_thresh to prevent write blocking with strictlimit

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

Message-Id: <20241025170222.0ced663e778935946ea1c9fa@linux-foundation.org>
Date: Fri, 25 Oct 2024 17:02:22 -0700
From: Andrew Morton <akpm@...ux-foundation.org>
To: Jim Zhao <jimzhao.ai@...il.com>
Cc: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-mm@...ck.org, willy@...radead.org
Subject: Re: [PATCH] mm/page-writeback: Raise wb_thresh to prevent write
 blocking with strictlimit

On Thu, 24 Oct 2024 15:29:19 +0800 Jim Zhao <jimzhao.ai@...il.com> wrote:

> > > 2. FUSE with Unstable Network Backends and Occasional Writes
> > > Not easy to reproduce, but when it occurs in this scenario, 
> > > it causes the write thread to experience more pauses and longer durations.
> 
> > Thanks, but it's still unclear how this impacts our users.  How lenghty
> > are these pauses?
> 
> The length is related to device writeback bandwidth.
> Under normal bandwidth, each pause may last around 4ms in several times as shown in the trace above(5 times).
> In extreme cases, fuse with unstable network backends,
> if pauses occur frequently and bandwidth is low, each pause can exceed 10ms, the total duration of pauses can accumulate to second.

Thanks.  I'll assume that the userspace impact isn't serious to warrant
a backport into -stable kernel.

If you disagree with this, please let me know and send along additional
changelog text which helps others understand why we think our users
will significantly benefit from this change.