Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1603642

Re: [PATCH v4] mm/vmscan: more restrictive condition for retry in do_try_to_free_pages

Show all headers | View raw

On Fri 17-03-17 14:39:28, Johannes Weiner wrote:
> On Wed, Mar 15, 2017 at 07:36:48PM +0800, Yisheng Xie wrote:
> > @@ -100,6 +100,9 @@ struct scan_control {
> >  	/* Can cgroups be reclaimed below their normal consumption range? */
> >  	unsigned int may_thrash:1;
> >  
> > +	/* Did we have any memcg protected by the low limit */
> > +	unsigned int memcg_low_protection:1;
> 
> These are both bad names. How about the following pair?
> 
> 	/*
> 	 * Cgroups are not reclaimed below their configured memory.low,
> 	 * unless we threaten to OOM. If any cgroups are skipped due to
> 	 * memory.low and nothing was reclaimed, go back for memory.low.
> 	 */
> 	unsigned int memcg_low_skipped:1
> 	unsigned int memcg_low_reclaim:1;

yes this is much better

> 
> > @@ -2557,6 +2560,8 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc)
> >  			unsigned long scanned;
> >  
> >  			if (mem_cgroup_low(root, memcg)) {
> > +				sc->memcg_low_protection = 1;
> > +
> >  				if (!sc->may_thrash)
> >  					continue;
> 
> 				if (!sc->memcg_low_reclaim) {
> 					sc->memcg_low_skipped = 1;
> 					continue;
> 				}
> 
> >  				mem_cgroup_events(memcg, MEMCG_LOW, 1);
> > @@ -2808,7 +2813,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
> >  		return 1;
> >  
> >  	/* Untapped cgroup reserves?  Don't OOM, retry. */
> > -	if (!sc->may_thrash) {
> > +	if (sc->memcg_low_protection && !sc->may_thrash) {
> 
> 	if (sc->memcg_low_skipped) {
> 		[...]
> 		sc->memcg_low_reclaim = 1;

you need to set memcg_low_skipped = 0 here, right? Otherwise we do not
have break out of the loop. Or am I missing something?

> 		goto retry;
> 	}

-- 
Michal Hocko
SUSE Labs

Back to linux.kernel | Previous | Next — Previous in thread | Find similar | Unroll thread

Thread

[PATCH v4] mm/vmscan: more restrictive condition for retry in do_try_to_free_pages Yisheng Xie <xieyisheng1@huawei.com> - 2017-03-15 12:50 +0100
  Re: [PATCH v4] mm/vmscan: more restrictive condition for retry in  do_try_to_free_pages Michal Hocko <mhocko@kernel.org> - 2017-03-15 13:50 +0100
    Re: [PATCH v4] mm/vmscan: more restrictive condition for retry in  do_try_to_free_pages Yisheng Xie <xieyisheng1@huawei.com> - 2017-03-16 11:10 +0100
  Re: [PATCH v4] mm/vmscan: more restrictive condition for retry in  do_try_to_free_pages Johannes Weiner <hannes@cmpxchg.org> - 2017-03-17 16:30 +0100
    Re: [PATCH v4] mm/vmscan: more restrictive condition for retry in  do_try_to_free_pages Michal Hocko <mhocko@kernel.org> - 2017-03-17 19:10 +0100
  Re: [PATCH v4] mm/vmscan: more restrictive condition for retry in  do_try_to_free_pages Johannes Weiner <hannes@cmpxchg.org> - 2017-03-17 19:50 +0100
    Re: [PATCH v4] mm/vmscan: more restrictive condition for retry in  do_try_to_free_pages Johannes Weiner <hannes@cmpxchg.org> - 2017-03-17 22:30 +0100
    Re: [PATCH v4] mm/vmscan: more restrictive condition for retry in  do_try_to_free_pages Michal Hocko <mhocko@kernel.org> - 2017-03-17 22:50 +0100

csiph-web