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authorTejun Heo <tj@kernel.org>2015-05-22 18:23:33 -0400
committerJens Axboe <axboe@fb.com>2015-06-02 08:38:13 -0600
commit841710aa6e4acd066ab9fe8c8cb6f4e4e6709d83 (patch)
tree90a5ea381b69d23dfbd4704d1177c54c60bca3b0 /mm/backing-dev.c
parent947e9762a8ddefda38aa21e249e6a4fec215cd12 (diff)
downloadlwn-841710aa6e4acd066ab9fe8c8cb6f4e4e6709d83.tar.gz
lwn-841710aa6e4acd066ab9fe8c8cb6f4e4e6709d83.zip
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/backing-dev.c')
-rw-r--r--mm/backing-dev.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 9c8b7b5a0eee..84ebf7c8d006 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -482,6 +482,7 @@ static void cgwb_release_workfn(struct work_struct *work)
css_put(wb->blkcg_css);
wb_congested_put(wb->congested);
+ fprop_local_destroy_percpu(&wb->memcg_completions);
percpu_ref_exit(&wb->refcnt);
wb_exit(wb);
kfree_rcu(wb, rcu);
@@ -548,9 +549,13 @@ static int cgwb_create(struct backing_dev_info *bdi,
if (ret)
goto err_wb_exit;
+ ret = fprop_local_init_percpu(&wb->memcg_completions, gfp);
+ if (ret)
+ goto err_ref_exit;
+
wb->congested = wb_congested_get_create(bdi, blkcg_css->id, gfp);
if (!wb->congested)
- goto err_ref_exit;
+ goto err_fprop_exit;
wb->memcg_css = memcg_css;
wb->blkcg_css = blkcg_css;
@@ -587,6 +592,8 @@ static int cgwb_create(struct backing_dev_info *bdi,
err_put_congested:
wb_congested_put(wb->congested);
+err_fprop_exit:
+ fprop_local_destroy_percpu(&wb->memcg_completions);
err_ref_exit:
percpu_ref_exit(&wb->refcnt);
err_wb_exit: