path: root/block
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authorTejun Heo <>2014-02-08 10:36:58 -0500
committerTejun Heo <>2014-02-08 10:36:58 -0500
commit073219e995b4a3f8cf1ce8228b7ef440b6994ac0 (patch)
treed140fc2e94bd8fd09270286b7267fb087a79f288 /block
parent3ed80a62bf959d34ebd4d553b026fbe7e6fbcc54 (diff)
cgroup: clean up cgroup_subsys names and initialization
cgroup_subsys is a bit messier than it needs to be. * The name of a subsys can be different from its internal identifier defined in cgroup_subsys.h. Most subsystems use the matching name but three - cpu, memory and perf_event - use different ones. * cgroup_subsys_id enums are postfixed with _subsys_id and each cgroup_subsys is postfixed with _subsys. cgroup.h is widely included throughout various subsystems, it doesn't and shouldn't have claim on such generic names which don't have any qualifier indicating that they belong to cgroup. * cgroup_subsys->subsys_id should always equal the matching cgroup_subsys_id enum; however, we require each controller to initialize it and then BUG if they don't match, which is a bit silly. This patch cleans up cgroup_subsys names and initialization by doing the followings. * cgroup_subsys_id enums are now postfixed with _cgrp_id, and each cgroup_subsys with _cgrp_subsys. * With the above, renaming subsys identifiers to match the userland visible names doesn't cause any naming conflicts. All non-matching identifiers are renamed to match the official names. cpu_cgroup -> cpu mem_cgroup -> memory perf -> perf_event * controllers no longer need to initialize ->subsys_id and ->name. They're generated in cgroup core and set automatically during boot. * Redundant cgroup_subsys declarations removed. * While updating BUG_ON()s in cgroup_init_early(), convert them to WARN()s. BUGging that early during boot is stupid - the kernel can't print anything, even through serial console and the trap handler doesn't even link stack frame properly for back-tracing. This patch doesn't introduce any behavior changes. v2: Rebased on top of fe1217c4f3f7 ("net: net_cls: move cgroupfs classid handling into core"). Signed-off-by: Tejun Heo <> Acked-by: Neil Horman <> Acked-by: "David S. Miller" <> Acked-by: "Rafael J. Wysocki" <> Acked-by: Michal Hocko <> Acked-by: Peter Zijlstra <> Acked-by: Aristeu Rozanski <> Acked-by: Ingo Molnar <> Acked-by: Li Zefan <> Cc: Johannes Weiner <> Cc: Balbir Singh <> Cc: KAMEZAWA Hiroyuki <> Cc: Serge E. Hallyn <> Cc: Vivek Goyal <> Cc: Thomas Graf <>
Diffstat (limited to 'block')
2 files changed, 4 insertions, 6 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 660d419..1cef07c 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -906,16 +906,14 @@ static int blkcg_can_attach(struct cgroup_subsys_state *css,
return ret;
-struct cgroup_subsys blkio_subsys = {
- .name = "blkio",
+struct cgroup_subsys blkio_cgrp_subsys = {
.css_alloc = blkcg_css_alloc,
.css_offline = blkcg_css_offline,
.css_free = blkcg_css_free,
.can_attach = blkcg_can_attach,
- .subsys_id = blkio_subsys_id,
.base_cftypes = blkcg_files,
* blkcg_activate_policy - activate a blkcg policy on a request_queue
@@ -1105,7 +1103,7 @@ int blkcg_policy_register(struct blkcg_policy *pol)
/* everything is in place, add intf files for the new policy */
if (pol->cftypes)
- WARN_ON(cgroup_add_cftypes(&blkio_subsys, pol->cftypes));
+ WARN_ON(cgroup_add_cftypes(&blkio_cgrp_subsys, pol->cftypes));
ret = 0;
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index 86154ea..453b528 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -186,7 +186,7 @@ static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css)
static inline struct blkcg *task_blkcg(struct task_struct *tsk)
- return css_to_blkcg(task_css(tsk, blkio_subsys_id));
+ return css_to_blkcg(task_css(tsk, blkio_cgrp_id));
static inline struct blkcg *bio_blkcg(struct bio *bio)