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authorLinus Torvalds <torvalds@linux-foundation.org>2017-12-11 17:10:05 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-12-11 17:10:05 -0800
commit085bec853afdbf3edf1b554defaac606a7e3f0c2 (patch)
tree130711ffc0da2b519b564bbb7bd3aebdaed3a6e8
parent72dd379e67fb6c4f4b0ed8ee36e9fed78227f352 (diff)
parentc2f31b79d510ec1a27138bdcf2d0ece1080be85e (diff)
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Merge branch 'for-4.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo: - Prateek posted a couple patches to fix a deadlock involving cpuset and workqueue. It unfortunately caused a different deadlock and the recent workqueue hotplug simplification removed the original deadlock, so Prateek's two patches are reverted for now. - The new stat code was missing u64_stats initialization. Fixed. - Doc and other misc changes * 'for-4.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: add warning about RT not being supported on cgroup2 Revert "cgroup/cpuset: remove circular dependency deadlock" Revert "cpuset: Make cpuset hotplug synchronous" cgroup: properly init u64_stats debug cgroup: use task_css_set instead of rcu_dereference cpuset: Make cpuset hotplug synchronous cgroup/cpuset: remove circular dependency deadlock
-rw-r--r--Documentation/cgroup-v2.txt7
-rw-r--r--kernel/cgroup/debug.c4
-rw-r--r--kernel/cgroup/stat.c8
3 files changed, 15 insertions, 4 deletions
diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt
index 779211fbb69f..2cddab7efb20 100644
--- a/Documentation/cgroup-v2.txt
+++ b/Documentation/cgroup-v2.txt
@@ -898,6 +898,13 @@ controller implements weight and absolute bandwidth limit models for
normal scheduling policy and absolute bandwidth allocation model for
realtime scheduling policy.
+WARNING: cgroup2 doesn't yet support control of realtime processes and
+the cpu controller can only be enabled when all RT processes are in
+the root cgroup. Be aware that system management software may already
+have placed RT processes into nonroot cgroups during the system boot
+process, and these processes may need to be moved to the root cgroup
+before the cpu controller can be enabled.
+
CPU Interface Files
~~~~~~~~~~~~~~~~~~~
diff --git a/kernel/cgroup/debug.c b/kernel/cgroup/debug.c
index 5f780d8f6a9d..9caeda610249 100644
--- a/kernel/cgroup/debug.c
+++ b/kernel/cgroup/debug.c
@@ -50,7 +50,7 @@ static int current_css_set_read(struct seq_file *seq, void *v)
spin_lock_irq(&css_set_lock);
rcu_read_lock();
- cset = rcu_dereference(current->cgroups);
+ cset = task_css_set(current);
refcnt = refcount_read(&cset->refcount);
seq_printf(seq, "css_set %pK %d", cset, refcnt);
if (refcnt > cset->nr_tasks)
@@ -96,7 +96,7 @@ static int current_css_set_cg_links_read(struct seq_file *seq, void *v)
spin_lock_irq(&css_set_lock);
rcu_read_lock();
- cset = rcu_dereference(current->cgroups);
+ cset = task_css_set(current);
list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
struct cgroup *c = link->cgrp;
diff --git a/kernel/cgroup/stat.c b/kernel/cgroup/stat.c
index 133b465691d6..1e111dd455c4 100644
--- a/kernel/cgroup/stat.c
+++ b/kernel/cgroup/stat.c
@@ -296,8 +296,12 @@ int cgroup_stat_init(struct cgroup *cgrp)
}
/* ->updated_children list is self terminated */
- for_each_possible_cpu(cpu)
- cgroup_cpu_stat(cgrp, cpu)->updated_children = cgrp;
+ for_each_possible_cpu(cpu) {
+ struct cgroup_cpu_stat *cstat = cgroup_cpu_stat(cgrp, cpu);
+
+ cstat->updated_children = cgrp;
+ u64_stats_init(&cstat->sync);
+ }
prev_cputime_init(&cgrp->stat.prev_cputime);