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

Mel Gorman
2011-07-14T06:19:19Z

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?

--
Mel Gorman
SUSE Labs