lkml.org 
[lkml]   [2010]   [Oct]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 00/17] [RFC] soft and dynamic dirty throttling limits
On Wed, Oct 13, 2010 at 04:26:12PM +0800, Wu Fengguang wrote:
> On Wed, Oct 13, 2010 at 11:07:33AM +0800, Dave Chinner wrote:
> > On Tue, Oct 12, 2010 at 10:17:16AM -0400, Christoph Hellwig wrote:
> > > Wu, what's the state of this series? It looks like we'll need it
> > > rather sooner than later - try to get at least the preparations in
> > > ASAP would be really helpful.
> >
> > Not ready in it's current form. This load (creating millions of 1
> > byte files in parallel):
> >
> > $ /usr/bin/time ./fs_mark -D 10000 -S0 -n 100000 -s 1 -L 63 \
> > > -d /mnt/scratch/0 -d /mnt/scratch/1 \
> > > -d /mnt/scratch/2 -d /mnt/scratch/3 \
> > > -d /mnt/scratch/4 -d /mnt/scratch/5 \
> > > -d /mnt/scratch/6 -d /mnt/scratch/7
> >
> > Locks up all the fs_mark processes spinning in traces like the
> > following and no further progress is made when the inode cache
> > fills memory.
>
> I reproduced the problem on a 6G/8p 2-socket 11-disk box.
>
> The root cause is, pageout() is somehow called with low scan priority,
> which deserves more investigation.
>
> The direct cause is, balance_dirty_pages() then keeps nr_dirty too low,
> which can be improved easily by not pushing down the soft dirty limit
> to less than 1-second worth of dirty pages.
>
> My test box has two nodes, and their memory usage are rather unbalanced:
> (Dave, maybe you have NUMA setup too?)

No, I'm running the test in a single node VM.

FYI, I'm running the test on XFS (16TB 12 disk RAID0 stripe), using
the mount options "inode64,nobarrier,logbsize=262144,delaylog".

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com


\
 
 \ /
  Last update: 2010-10-13 11:31    [W:1.976 / U:0.444 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site