diff options
| author | Tejun Heo <tj@kernel.org> | 2019-07-24 10:37:22 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-04-01 14:56:42 -0600 |
| commit | d866dbf6178713e37d2fec2870af00b345684e1a (patch) | |
| tree | f87bdafbbe76c032b7d56a4612d63d3c89167e1a /block | |
| parent | 1a323ea5356edbb3073dc59d51b9e6b86908857d (diff) | |
| download | lwn-d866dbf6178713e37d2fec2870af00b345684e1a.tar.gz lwn-d866dbf6178713e37d2fec2870af00b345684e1a.zip | |
blkcg: rename blkcg->cgwb_refcnt to ->online_pin and always use it
blkcg->cgwb_refcnt is used to delay blkcg offlining so that blkgs
don't get offlined while there are active cgwbs on them. However, it
ends up making offlining unordered sometimes causing parents to be
offlined before children.
To fix it, we want child blkcgs to pin the parents' online states
turning the refcnt into a more generic online pinning mechanism.
In prepartion,
* blkcg->cgwb_refcnt -> blkcg->online_pin
* blkcg_cgwb_get/put() -> blkcg_pin/unpin_online()
* Take them out of CONFIG_CGROUP_WRITEBACK
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-cgroup.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index c15a26096038..2acef6a64954 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -883,8 +883,8 @@ static void blkcg_css_offline(struct cgroup_subsys_state *css) /* this prevents anyone from attaching or migrating to this blkcg */ wb_blkcg_offline(blkcg); - /* put the base cgwb reference allowing step 2 to be triggered */ - blkcg_cgwb_put(blkcg); + /* put the base online pin allowing step 2 to be triggered */ + blkcg_unpin_online(blkcg); } /** @@ -983,11 +983,11 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css) } spin_lock_init(&blkcg->lock); + refcount_set(&blkcg->online_pin, 1); INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_NOWAIT | __GFP_NOWARN); INIT_HLIST_HEAD(&blkcg->blkg_list); #ifdef CONFIG_CGROUP_WRITEBACK INIT_LIST_HEAD(&blkcg->cgwb_list); - refcount_set(&blkcg->cgwb_refcnt, 1); #endif list_add_tail(&blkcg->all_blkcgs_node, &all_blkcgs); |