lkml.org 
[lkml]   [2007]   [Sep]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: A unresponsive file system can hang all I/O in the system on linux-2.6.23-rc6 (dirty_thresh problem?)
On Fri, 28 Sep 2007 13:00:53 -0400 Trond Myklebust <trond.myklebust@fys.uio.no> wrote:

> On Thu, 2007-09-27 at 23:50 -0700, Andrew Morton wrote:
>
> > Actually we perhaps could address this at the VFS level in another way.
> > Processes which are writing to the dead NFS server will eventually block in
> > balance_dirty_pages() once they've exceeded the memory limits and will
> > remain blocked until the server wakes up - that's the behaviour we want.
> >
> > What we _don't_ want to happen is for other processes which are writing to
> > other, non-dead devices to get collaterally blocked. We have patches which
> > might fix that queued for 2.6.24. Peter?
>
> Do these patches also cause the memory reclaimers to steer clear of
> devices that are congested (and stop waiting on a congested device if
> they see that it remains congested for a long period of time)? Most of
> the collateral blocking I see tends to happen in memory allocation...
>

No, they don't attempt to do that, but I suspect they put in place
infrastructure which could be used to improve direct-reclaimer latency. In
the throttle_vm_writeout() path, at least.

Do you know where the stalls are occurring? throttle_vm_writeout(), or via
direct calls to congestion_wait() from page_alloc.c and vmscan.c? (running
sysrq-w five or ten times will probably be enough to determine this)

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

\
 
 \ /
  Last update: 2007-09-28 20:53    [W:0.170 / U:0.008 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site