From: Chris Friesen <chris.friesen@genband.com>
To: Jan Kara <jack@suse.cz>
Cc: Alex Bligh <alex@alex.org.uk>, Michal Hocko <mhocko@suse.cz>,
linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org
Subject: Re: Local DoS through write heavy I/O on CFQ & Deadline
Date: Thu, 18 Oct 2012 16:13:58 -0600 [thread overview]
Message-ID: <50807F26.5070106@genband.com> (raw)
In-Reply-To: <20121018212845.GB17646@quack.suse.cz>
On 10/18/2012 03:28 PM, Jan Kara wrote:
> Yeah, ionice has its limitations. The problem is that all buffered
> writes happen just into memory (so completely independently of ionice
> settings). Subsequent writing of dirty memory to disk happens using flusher
> thread which is a kernel process and it doesn't know anything about IO
> priority set for task which created the file. If you wrote the file with
> oflag=direct or oflag=sync you would see that ionice works as expected.
Has anyone looked at storing the ionice value with the buffered write
request such that the actual writes to disk could be sorted by priority
and done with the ionice level of the original caller?
Chris
next prev parent reply other threads:[~2012-10-18 22:14 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-11 12:23 Local DoS through write heavy I/O on CFQ & Deadline Alex Bligh
2012-10-11 13:46 ` Alan Cox
2012-10-12 12:57 ` Alex Bligh
2012-10-12 13:30 ` Michal Hocko
2012-10-12 14:48 ` Alex Bligh
2012-10-12 14:58 ` Michal Hocko
2012-10-12 16:29 ` Alex Bligh
2012-10-13 13:53 ` Hillf Danton
2012-10-13 19:33 ` Alex Bligh
2012-10-14 2:43 ` Hillf Danton
2012-10-15 8:17 ` Michal Hocko
2012-10-18 21:28 ` Jan Kara
2012-10-18 22:13 ` Chris Friesen [this message]
2012-10-18 22:24 ` Jan Kara
2012-10-14 21:17 ` Dave Chinner
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