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authorTejun Heo <tj@kernel.org>2015-05-23 01:23:33 +0300
committerJens Axboe <axboe@fb.com>2015-06-02 17:38:13 +0300
commit841710aa6e4acd066ab9fe8c8cb6f4e4e6709d83 (patch)
tree90a5ea381b69d23dfbd4704d1177c54c60bca3b0 /mm/memcontrol.c
parent947e9762a8ddefda38aa21e249e6a4fec215cd12 (diff)
downloadlinux-841710aa6e4acd066ab9fe8c8cb6f4e4e6709d83.tar.xz
writeback: implement memcg wb_domain
Dirtyable memory is distributed to a wb (bdi_writeback) according to the relative bandwidth the wb is writing out in the whole system. This distribution is global - each wb is measured against all other wb's and gets the proportinately sized portion of the memory in the whole system. For cgroup writeback, the amount of dirtyable memory is scoped by memcg and thus each wb would need to be measured and controlled in its memcg. IOW, a wb will belong to two writeback domains - the global and memcg domains. The previous patches laid the groundwork to support the two wb_domains and this patch implements memcg wb_domain. memcg->cgwb_domain is initialized on css online and destroyed on css release, wb->memcg_completions is added, and __wb_writeout_inc() is updated to increment completions against both global and memcg wb_domains. The following patches will update balance_dirty_pages() and its subroutines to actually consider memcg wb_domain for throttling. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r--mm/memcontrol.c39
1 files changed, 39 insertions, 0 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 701cbee9acba..ce113ddf2fb5 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -345,6 +345,7 @@ struct mem_cgroup {
#ifdef CONFIG_CGROUP_WRITEBACK
struct list_head cgwb_list;
+ struct wb_domain cgwb_domain;
#endif
/* List of events which userspace want to receive */
@@ -3994,6 +3995,37 @@ struct list_head *mem_cgroup_cgwb_list(struct mem_cgroup *memcg)
return &memcg->cgwb_list;
}
+static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
+{
+ return wb_domain_init(&memcg->cgwb_domain, gfp);
+}
+
+static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
+{
+ wb_domain_exit(&memcg->cgwb_domain);
+}
+
+struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
+
+ if (!memcg->css.parent)
+ return NULL;
+
+ return &memcg->cgwb_domain;
+}
+
+#else /* CONFIG_CGROUP_WRITEBACK */
+
+static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
+{
+ return 0;
+}
+
+static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
+{
+}
+
#endif /* CONFIG_CGROUP_WRITEBACK */
/*
@@ -4380,9 +4412,15 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
if (!memcg->stat)
goto out_free;
+
+ if (memcg_wb_domain_init(memcg, GFP_KERNEL))
+ goto out_free_stat;
+
spin_lock_init(&memcg->pcp_counter_lock);
return memcg;
+out_free_stat:
+ free_percpu(memcg->stat);
out_free:
kfree(memcg);
return NULL;
@@ -4409,6 +4447,7 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg)
free_mem_cgroup_per_zone_info(memcg, node);
free_percpu(memcg->stat);
+ memcg_wb_domain_exit(memcg);
kfree(memcg);
}