Re: Local DoS through write heavy I/O on CFQ & Deadline

From: Hillf Danton
Date: Sat Oct 13 2012 - 09:53:17 EST


Hi Alex,

On Sat, Oct 13, 2012 at 12:29 AM, Alex Bligh <alex@xxxxxxxxxxx> wrote:
> Michael,
>
> --On 12 October 2012 16:58:39 +0200 Michal Hocko <mhocko@xxxxxxx> wrote:
>
>> Once dirty_ratio (resp. dirty_bytes) limit is hit then the process which
>> writes gets throttled. If this is not the case then there is a bug in
>> the throttling code.
>
>
> I believe that is the problem.

Take a look at the "wait for writeback" problem please.

Linux 3.0+ Disk performance problem - wrong pdflush behaviour
https://lkml.org/lkml/2012/10/10/412

Hillf
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