lkml.org 
[lkml]   [2010]   [Sep]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
DateTue, 14 Sep 2010 16:33:38 +0800
FromWu Fengguang <>
SubjectRe: [PATCH 05/17] writeback: quit throttling when signal pending
On Tue, Sep 14, 2010 at 04:23:56PM +0800, KOSAKI Motohiro wrote:
> > Subject: writeback: quit throttling when fatal signal pending
> > From: Wu Fengguang <fengguang.wu@intel.com>
> > Date: Wed Sep 08 17:40:22 CST 2010
> >
> > This allows quick response to Ctrl-C etc. for impatient users.
> >
> > It mainly helps the rare bdi/global dirty exceeded cases.
> > In the normal case of not exceeded, it will quit the loop anyway.
> >
> > CC: Neil Brown <neilb@suse.de>
> > Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
> > ---
> > mm/page-writeback.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > --- linux-next.orig/mm/page-writeback.c 2010-09-12 13:25:23.000000000 +0800
> > +++ linux-next/mm/page-writeback.c 2010-09-13 11:39:33.000000000 +0800
> > @@ -552,6 +552,9 @@ static void balance_dirty_pages(struct a
> > __set_current_state(TASK_INTERRUPTIBLE);
> > io_schedule_timeout(pause);
> >
> > + if (fatal_signal_pending(current))
> > + break;
> > +
> > check_exceeded:
> > /*
> > * The bdi thresh is somehow "soft" limit derived from the
>
> I think we need to change callers (e.g. generic_perform_write) too.
> Otherwise, plenty write + SIGKILL combination easily exceed dirty limit.
> It mean we can see strange OOM.

If it's dangerous, we can do without this patch. The users can still
get quick response in normal case after all.

However, I suspect the process is guaranteed to exit on
fatal_signal_pending, so it won't dirty more pages :)

Thanks,
Fengguang


\
 
 \ /
  Last update: 2010-09-14 10:37    [from the cache]
©2003-2010