Messages in this thread | | | Date | Tue, 7 Jul 2009 21:23:51 +0800 | From | Wu Fengguang <> | Subject | Re: [RFC PATCH 1/2] vmscan don't isolate too many pages |
| |
On Tue, Jul 07, 2009 at 05:47:13PM +0800, KOSAKI Motohiro wrote: > Subject: [PATCH] vmscan don't isolate too many pages > > If the system have plenty threads or processes, concurrent reclaim can > isolate very much pages. > > And if other processes isolate _all_ pages on lru, the reclaimer can't find > any reclaimable page and it makes accidental OOM. > > The solusion is, we should restrict maximum number of isolated pages. > (this patch use inactive_page/2)
Now I think this is a better solution than per-cpu throttling :) Will test it tomorrow.
Acked-by: Wu Fengguang <fengguang.wu@intel.com>
> > FAQ > ------- > Q: Why do you compared zone accumulate pages, not individual zone pages? > A: If we check individual zone, #-of-reclaimer is restricted by smallest zone. > it mean decreasing the performance of the system having small dma zone. > > > Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> > --- > mm/page_alloc.c | 27 +++++++++++++++++++++++++++ > 1 file changed, 27 insertions(+) > > Index: b/mm/page_alloc.c > =================================================================== > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -1721,6 +1721,28 @@ gfp_to_alloc_flags(gfp_t gfp_mask) > return alloc_flags; > } > > +static bool too_many_isolated(struct zonelist *zonelist, > + enum zone_type high_zoneidx, nodemask_t *nodemask) > +{ > + unsigned long nr_inactive = 0; > + unsigned long nr_isolated = 0; > + struct zoneref *z; > + struct zone *zone; > + > + for_each_zone_zonelist_nodemask(zone, z, zonelist, > + high_zoneidx, nodemask) { > + if (!populated_zone(zone)) > + continue; > + > + nr_inactive += zone_page_state(zone, NR_INACTIVE_ANON); > + nr_inactive += zone_page_state(zone, NR_INACTIVE_FILE); > + nr_isolated += zone_page_state(zone, NR_ISOLATED_ANON); > + nr_isolated += zone_page_state(zone, NR_ISOLATED_FILE); > + } > + > + return nr_isolated > nr_inactive; > +} > + > static inline struct page * > __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, > struct zonelist *zonelist, enum zone_type high_zoneidx, > @@ -1789,6 +1811,11 @@ rebalance: > if (p->flags & PF_MEMALLOC) > goto nopage; > > + if (too_many_isolated(gfp_mask, zonelist, high_zoneidx, nodemask)) { > + schedule_timeout_uninterruptible(HZ/10); > + goto restart; > + } > + > /* Try direct reclaim and then allocating */ > page = __alloc_pages_direct_reclaim(gfp_mask, order, > zonelist, high_zoneidx, >
| |