linux-kernel - [RFC] ext3: per-process soft-syncing data=ordered mode

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

Message-Id: <200801242336.00340.a1426z@gawab.com>
Date:	Thu, 24 Jan 2008 23:36:00 +0300
From:	Al Boldi <a1426z@...ab.com>
To:	linux-fsdevel@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org
Subject: [RFC] ext3: per-process soft-syncing data=ordered mode

Greetings!

data=ordered mode has proven reliable over the years, and it does this by 
ordering filedata flushes before metadata flushes.  But this sometimes 
causes contention in the order of a 10x slowdown for certain apps, either 
due to the misuse of fsync or due to inherent behaviour like db's, as well 
as inherent starvation issues exposed by the data=ordered mode.

data=writeback mode alleviates data=order mode slowdowns, but only works 
per-mount and is too dangerous to run as a default mode.

This RFC proposes to introduce a tunable which allows to disable fsync and 
changes ordered into writeback writeout on a per-process basis like this:

      echo 1 > /proc/`pidof process`/softsync

Your comments are much welcome!

Thanks!

--
Al

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/