On Sat 11-08-12 01:49:25, KAMEZAWA Hiroyuki wrote: > (2012/08/11 0:42), Michal Hocko wrote: > >On Thu 09-08-12 17:01:10, Glauber Costa wrote: > >[...] > >>@@ -2317,18 +2318,18 @@ static int mem_cgroup_do_charge(struct mem_cgroup > >>*memcg, gfp_t gfp_mask, > >> } else > >> mem_over_limit = mem_cgroup_from_res_counter(fail_res, res); > >> /* > >>- * nr_pages can be either a huge page (HPAGE_PMD_NR), a batch > >>- * of regular pages (CHARGE_BATCH), or a single regular page (1). > >>- * > >> * Never reclaim on behalf of optional batching, retry with a > >> * single page instead. > >> */ > >>- if (nr_pages == CHARGE_BATCH) > >>+ if (nr_pages > min_pages) > >> return CHARGE_RETRY; > > > >This is dangerous because THP charges will be retried now while they > >previously failed with CHARGE_NOMEM which means that we will keep > >attempting potentially endlessly. > > with THP, I thought nr_pages == min_pages, and no retry.
right you are. > >Why cannot we simply do if (nr_pages < CHARGE_BATCH) and get rid of the > >min_pages altogether? > > Hm, I think a slab can be larger than CHARGE_BATCH. > > >Also the comment doesn't seem to be valid anymore. > > > I agree it's not clean. Because our assumption on nr_pages are changed, > I think this behavior should not depend on nr_pages value.. > Shouldn't we have a flag to indicate "trial-for-batched charge" ? dunno, it would require a new parameter anyway (because abusing gfp doesn't seem great idea). > > > Thanks, > -Kame > > > > > -- > To unsubscribe from this list: send the line "unsubscribe cgroups" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
