Re: [PATCH 1/5] mm: vmscan: Do not writeback filesystem pages in direct reclaim

KAMEZAWA Hiroyuki
2011-07-14T06:24:31Z

On Thu, 14 Jul 2011 07:19:15 +0100
Mel Gorman <mgorman@suse.de> wrote:

> On Thu, Jul 14, 2011 at 10:38:01AM +0900, KAMEZAWA Hiroyuki wrote:
> > > @@ -825,6 +825,15 @@ static unsigned long shrink_page_list(struct list_head *page_list,
> > > if (PageDirty(page)) {
> > > nr_dirty++;
> > >
> > > + /*
> > > + * Only kswapd can writeback filesystem pages to
> > > + * avoid risk of stack overflow
> > > + */
> > > + if (page_is_file_cache(page) && !current_is_kswapd()) {
> > > + inc_zone_page_state(page, NR_VMSCAN_WRITE_SKIP);
> > > + goto keep_locked;
> > > + }
> > > +
> >
> >
> > This will cause tons of memcg OOM kill because we have no help of kswapd (now).
> >
> > Could you make this
> >
> > if (scanning_global_lru(sc) && page_is_file_cache(page) && !current_is_kswapd())
> > ...
> >
>
> I can, but as Christoph points out, the request is already being
> ignored so how will it help?
>

Hmm, ok, please go as you do now. I'll do hurry up to implement dirty_ratio by myself
without waiting for original patch writer. I think his latest version was really
near to be merged... I'll start rebase his one to mmotm in this end of month.

Thanks,
-Kame