Messages in this thread Patch in this message | | | Date | Fri, 13 Jun 2008 18:30:15 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | [PATCH 2/6] memcg: handle limit change |
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Add callback for resize_limit().
After this patch, memcg's usage will be reduced to new limit. If it cannot, -EBUSY will be return to write() syscall.
And this patch tries to free all pages at force_empty by reusing shrink function.
Change log: xxx -> v4 - cut out from memcg hierarhcy patch set. - added retry_count as new arguments.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
--- Documentation/controllers/memory.txt | 3 -- mm/memcontrol.c | 47 ++++++++++++++++++++++++++++++++--- 2 files changed, 45 insertions(+), 5 deletions(-)
Index: linux-2.6.26-rc5-mm3/mm/memcontrol.c =================================================================== --- linux-2.6.26-rc5-mm3.orig/mm/memcontrol.c +++ linux-2.6.26-rc5-mm3/mm/memcontrol.c @@ -779,6 +779,44 @@ int mem_cgroup_shrink_usage(struct mm_st } /* + * A callback for shrinking limit, Always GFP_KERNEL. + */ +int mem_cgroup_shrink_usage_to(struct res_counter *res, unsigned long long val, + int retry_count) +{ + struct mem_cgroup *memcg = container_of(res, struct mem_cgroup, res); + + if (retry_count > MEM_CGROUP_RECLAIM_RETRIES) + return -EBUSY; + +retry: + if (res_counter_check_under_val(res, val)) + return 0; + + cond_resched(); + if (try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL) == 0) + return 0; /* no progress...*/ + + goto retry; +} + +/* + * Must be called under there is no users on this cgroup. + */ +static void memcg_shrink_usage_all(struct mem_cgroup *memcg) +{ + int retry_count = 0; + int ret = 0; + + while (!ret && !res_counter_check_under_val(&memcg->res, 0)) { + ret = mem_cgroup_shrink_usage_to(&memcg->res, 0, retry_count); + retry_count++; + } + + return; +} + +/* * This routine traverse page_cgroup in given list and drop them all. * *And* this routine doesn't reclaim page itself, just removes page_cgroup. */ @@ -835,9 +873,10 @@ static int mem_cgroup_force_empty(struct * active_list <-> inactive_list while we don't take a lock. * So, we have to do loop here until all lists are empty. */ - while (mem->res.usage > 0) { + while (!res_counter_check_under_val(&mem->res, 0)) { if (atomic_read(&mem->css.cgroup->count) > 0) goto out; + memcg_shrink_usage_all(mem); for_each_node_state(node, N_POSSIBLE) for (zid = 0; zid < MAX_NR_ZONES; zid++) { struct mem_cgroup_per_zone *mz; @@ -1046,13 +1085,15 @@ static void mem_cgroup_free(struct mem_c vfree(mem); } +struct res_counter_ops root_ops = { + .shrink_usage = mem_cgroup_shrink_usage_to, +}; static struct cgroup_subsys_state * mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) { struct mem_cgroup *mem; int node; - if (unlikely((cont->parent) == NULL)) { mem = &init_mem_cgroup; page_cgroup_cache = KMEM_CACHE(page_cgroup, SLAB_PANIC); @@ -1062,7 +1103,7 @@ mem_cgroup_create(struct cgroup_subsys * return ERR_PTR(-ENOMEM); } - res_counter_init(&mem->res); + res_counter_init_ops(&mem->res, &root_ops); for_each_node_state(node, N_POSSIBLE) if (alloc_mem_cgroup_per_zone_info(mem, node)) Index: linux-2.6.26-rc5-mm3/Documentation/controllers/memory.txt =================================================================== --- linux-2.6.26-rc5-mm3.orig/Documentation/controllers/memory.txt +++ linux-2.6.26-rc5-mm3/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
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