Shrinking memory usage at limit change. This is an enhancement. based on res_counter-limit-change-ebusy.patch Changelog: v3 -> v4 - core logic is separated into two parts. (reuse the function later.) - added cond_resched() again. 1. I was pointed out that alloc_pages() does cond_resched() after try_to_free_pages(). 2. This routine is called by an user. A user can set 'nice' in general. Changelog: v2 -> v3 - supported interrupt by signal. (A user can stop limit change by Ctrl-C.) Changelog: v1 -> v2 - adjusted to be based on write_string() patch set - removed backword goto. - removed unneccesary cond_resched(). Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Documentation/controllers/memory.txt | 3 - mm/memcontrol.c | 73 +++++++++++++++++++++++++++++++++-- 2 files changed, 70 insertions(+), 6 deletions(-) Index: mmtom-stamp-2008-07-15-15-39/mm/memcontrol.c =================================================================== --- mmtom-stamp-2008-07-15-15-39.orig/mm/memcontrol.c +++ mmtom-stamp-2008-07-15-15-39/mm/memcontrol.c @@ -804,6 +804,55 @@ int mem_cgroup_shrink_usage(struct mm_st } /* + * Shrink routine works cooperatively with users rather than the kernel. + * So, + * - we have to check signals + * - we pass GFP_HIGHUSERMOVABLE. + * TODO?: + * - allow timeout + */ +static int mem_cgroup_shrink_usage_to(struct mem_cgroup *memcg, + unsigned long long val) +{ + int retry_count = MEM_CGROUP_RECLAIM_RETRIES; + int progress; + int ret; + + while (!res_counter_check_under_val(&memcg->res, val)) { + if (signal_pending(current)) { + ret = -EINTR; + break; + } + if (!retry_count) { + ret = -EBUSY; + break; + } + progress = try_to_free_mem_cgroup_pages(memcg, + GFP_HIGHUSER_MOVABLE); + if (!progress) + retry_count--; + cond_resched(); + } + return 0; +} + +int mem_cgroup_resize_limit(struct mem_cgroup *memcg, unsigned long long val) +{ + int ret = 0; + + do { + ret = mem_cgroup_shrink_usage_to(memcg, val); + if (ret < 0) + break; + /* memory usage shrinking succeed. */ + if (res_counter_set_limit(&memcg->res, val)) + break; + } while (1); + return ret; +} + + +/* * This routine traverse page_cgroup in given list and drop them all. * *And* this routine doesn't reclaim page itself, just removes page_cgroup. */ @@ -883,13 +932,29 @@ static u64 mem_cgroup_read(struct cgroup return res_counter_read_u64(&mem_cgroup_from_cont(cont)->res, cft->private); } - +/* + * The user of this function is... + * RES_LIMIT. + */ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft, const char *buffer) { - return res_counter_write(&mem_cgroup_from_cont(cont)->res, - cft->private, buffer, - res_counter_memparse_write_strategy); + struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); + unsigned long long val; + int ret; + + switch (cft->private) { + case RES_LIMIT: + /* This function does all necessary parse...reuse it */ + ret = res_counter_memparse_write_strategy(buffer, &val); + if (!ret) + ret = mem_cgroup_resize_limit(memcg, val); + break; + default: + ret = -EINVAL; /* should be BUG() ? */ + break; + } + return ret; } static int mem_cgroup_reset(struct cgroup *cont, unsigned int event) Index: mmtom-stamp-2008-07-15-15-39/Documentation/controllers/memory.txt =================================================================== --- mmtom-stamp-2008-07-15-15-39.orig/Documentation/controllers/memory.txt +++ mmtom-stamp-2008-07-15-15-39/Documentation/controllers/memory.txt @@ -242,8 +242,7 @@ rmdir() if there are no tasks. 1. Add support for accounting huge pages (as a separate controller) 2. Make per-cgroup scanner reclaim not-shared pages first 3. Teach controller to account for shared-pages -4. Start reclamation when the limit is lowered -5. Start reclamation in the background when the limit is +4. Start reclamation in the background when the limit is not yet hit but the usage is getting closer Summary _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers