On Thu 11-01-18 15:21:33, Andrey Ryabinin wrote: > > > On 01/11/2018 01:42 PM, Michal Hocko wrote: > > On Wed 10-01-18 15:43:17, Andrey Ryabinin wrote: > > [...] > >> @@ -2506,15 +2480,13 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg, > >> if (!ret) > >> break; > >> > >> - try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, !memsw); > >> - > >> - curusage = page_counter_read(counter); > >> - /* Usage is reduced ? */ > >> - if (curusage >= oldusage) > >> - retry_count--; > >> - else > >> - oldusage = curusage; > >> - } while (retry_count); > >> + usage = page_counter_read(counter); > >> + if (!try_to_free_mem_cgroup_pages(memcg, usage - limit, > >> + GFP_KERNEL, !memsw)) { > > > > If the usage drops below limit in the meantime then you get underflow > > and reclaim the whole memcg. I do not think this is a good idea. This > > can also lead to over reclaim. Why don't you simply stick with the > > original SWAP_CLUSTER_MAX (aka 1 for try_to_free_mem_cgroup_pages)? > > > > Because, if new limit is gigabytes bellow the current usage, retrying to set > new limit after reclaiming only 32 pages seems unreasonable. Who would do insanity like that? > @@ -2487,8 +2487,8 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg, > if (!ret) > break; > > - usage = page_counter_read(counter); > - if (!try_to_free_mem_cgroup_pages(memcg, usage - limit, > + nr_pages = max_t(long, 1, page_counter_read(counter) - limit); > + if (!try_to_free_mem_cgroup_pages(memcg, nr_pages, > GFP_KERNEL, !memsw)) { > ret = -EBUSY; > break; How does this address the over reclaim concern? -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html