Merge tag 'cgroup-for-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup updates from Tejun Heo:

 - Last cycle deferred css teardown on cgroup removal until the cgroup
   depopulated, so a css is not taken offline while tasks can still
   reference it. Disabling a controller through cgroup.subtree_control
   still had the same problem. This reworks the deferral from per-cgroup
   to per-css so that path is covered too.

 - New RDMA controller monitoring files: rdma.peak for per-device peak
   usage and rdma.events / rdma.events.local for resource-limit
   exhaustion. The max-limit parser was rewritten, fixing two input
   parsing bugs.

 - cpuset: fix a sched-domain leak on the domain-rebuild failure path
   and skip a redundant hardwall ancestor scan on v2.

 - Misc: pair the remaining lockless cgroup.max.* reads with WRITE_ONCE,
   assorted selftest robustness fixes, and doc path corrections.

* tag 'cgroup-for-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (22 commits)
  cgroup: Migrate tasks to the root css when a controller is rebound
  docs: cgroup: Fix stale source file paths
  cgroup/cpuset: Free sched domains on rebuild guard failure
  cgroup: pair max limit READ_ONCE() with WRITE_ONCE()
  selftests/cgroup: enable memory controller in hugetlb memcg test
  cgroup/rdma: Drop unnecessary READ_ONCE() on event counters
  cgroup: Defer kill_css_finish() in cgroup_apply_control_disable()
  cgroup: Add per-subsys-css kill_css_finish deferral
  cgroup: Move populated counters to cgroup_subsys_state
  cgroup: Annotate unlocked nr_populated_* accesses with READ_ONCE/WRITE_ONCE
  cgroup: Inline cgroup_has_tasks() in cgroup.h
  cgroup/rdma: document rdma.peak, rdma.events and rdma.events.local
  cgroup/rdma: add rdma.events.local for per-cgroup allocation failure attribution
  cgroup/rdma: add rdma.events to track resource limit exhaustion
  cgroup/rdma: add rdma.peak for per-device peak usage tracking
  selftests/cgroup: check malloc return value in alloc_anon functions
  cgroup/cpuset: Skip hardwall ancestor scan in cpuset v2 in cpuset_current_node_allowed()
  selftests/cgroup: fix misleading debug message in test_cgfreezer_time_child
  selftests/cgroup: fix child process escaping to parent cleanup in test_cpucg_nice
  selftests/cgroup: Add NULL check after malloc in cgroup_util.c
  ...

3 files changed, 55 insertions, 2 deletions

diff --git a/Documentation/admin-guide/cgroup-v1/cgroups.rst b/Documentation/admin-guide/cgroup-v1/cgroups.rst
index 463f98453323..e501f45ea93f 100644
--- a/Documentation/admin-guide/cgroup-v1/cgroups.rst
+++ b/Documentation/admin-guide/cgroup-v1/cgroups.rst
@@ -525,7 +525,7 @@ cgroup. It may also be taken to prevent cgroups from being
 modified, but more specific locks may be more appropriate in that
 situation.
 
-See kernel/cgroup.c for more details.
+See kernel/cgroup/cgroup.c for more details.
 
 Subsystems can take/release the cgroup_mutex via the functions
 cgroup_lock()/cgroup_unlock().
diff --git a/Documentation/admin-guide/cgroup-v1/memcg_test.rst b/Documentation/admin-guide/cgroup-v1/memcg_test.rst
index 7c7cd457cf69..ebedbc3c3f9c 100644
--- a/Documentation/admin-guide/cgroup-v1/memcg_test.rst
+++ b/Documentation/admin-guide/cgroup-v1/memcg_test.rst
@@ -321,7 +321,7 @@ Under below explanation, we assume CONFIG_SWAP=y.
 ----------------------
 
 	Memory controller implements memory thresholds using cgroups notification
-	API. You can use tools/cgroup/cgroup_event_listener.c to test it.
+	API. You can use samples/cgroup/cgroup_event_listener.c to test it.
 
 	(Shell-A) Create cgroup and run event listener::
 
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 6efd0095ed99..993446ab66d0 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -2785,6 +2785,59 @@ RDMA Interface Files
 	  mlx4_0 hca_handle=1 hca_object=20
 	  ocrdma1 hca_handle=1 hca_object=23
 
+  rdma.peak
+	A read-only nested-keyed file that exists for all the cgroups
+	except root.  It shows the historical high watermark of
+	resource usage per device since the cgroup was created.
+
+	An example for mlx4 and ocrdma device follows::
+
+	  mlx4_0 hca_handle=1 hca_object=20
+	  ocrdma1 hca_handle=0 hca_object=23
+
+  rdma.events
+	A read-only nested-keyed file which exists on non-root
+	cgroups.  The following nested keys are defined.
+
+	  max
+		The number of times a process in this cgroup or its
+		descendants attempted an RDMA resource allocation that
+		was rejected because a rdma.max limit in the subtree
+		was reached.  This is a hierarchical counter: the event
+		is propagated upward to all ancestor cgroups.  A value
+		change in this file generates a file modified event.
+
+	  alloc_fail
+		The number of RDMA resource allocation attempts that
+		originated in this cgroup or its descendants and failed
+		due to a rdma.max limit being reached.  This is a
+		hierarchical counter propagated upward.
+
+	An example for mlx4 device follows::
+
+	  mlx4_0 hca_handle.max=5 hca_handle.alloc_fail=3 hca_object.max=0 hca_object.alloc_fail=0
+
+  rdma.events.local
+	Similar to rdma.events but the fields in the file are local
+	to the cgroup i.e. not hierarchical.  The file modified event
+	generated on this file reflects only the local events.
+
+	The following nested keys are defined.
+
+	  max
+		The number of times a process in this cgroup or its
+		descendants attempted an RDMA resource allocation that
+		was rejected because this cgroup's own rdma.max limit
+		was reached.
+	  alloc_fail
+		The number of RDMA resource allocation attempts
+		originating from this cgroup that failed due to this
+		cgroup's or an ancestor's rdma.max limit.
+
+	An example for mlx4 device follows::
+
+	  mlx4_0 hca_handle.max=5 hca_handle.alloc_fail=0 hca_object.max=0 hca_object.alloc_fail=0
+
 DMEM
 ----