Merge branch 'for-4.20' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie...

[sfrench/cifs-2.6.git] / Documentation / admin-guide / cgroup-v2.rst

diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index caf36105a1c7b50b3b76d53afcb2d75d094fee77..476722b7b6367ca38bf0e3263f3e132b515dcfd6 100644 (file)
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -966,6 +966,12 @@ All time durations are in microseconds.
        $PERIOD duration.  "max" for $MAX indicates no limit.  If only
        one number is written, $MAX is updated.
 
+  cpu.pressure
+       A read-only nested-key file which exists on non-root cgroups.
+
+       Shows pressure stall information for CPU. See
+       Documentation/accounting/psi.txt for details.
+
 
 Memory
 ------
@@ -1127,6 +1133,10 @@ PAGE_SIZE multiple when read back.
                disk readahead.  For now OOM in memory cgroup kills
                tasks iff shortage has happened inside page fault.
 
+               This event is not raised if the OOM killer is not
+               considered as an option, e.g. for failed high-order
+               allocations.
+
          oom_kill
                The number of processes belonging to this cgroup
                killed by any kind of OOM killer.
@@ -1271,6 +1281,12 @@ PAGE_SIZE multiple when read back.
        higher than the limit for an extended period of time.  This
        reduces the impact on the workload and memory management.
 
+  memory.pressure
+       A read-only nested-key file which exists on non-root cgroups.
+
+       Shows pressure stall information for memory. See
+       Documentation/accounting/psi.txt for details.
+
 
 Usage Guidelines
 ~~~~~~~~~~~~~~~~
@@ -1408,6 +1424,12 @@ IO Interface Files
 
          8:16 rbps=2097152 wbps=max riops=max wiops=max
 
+  io.pressure
+       A read-only nested-key file which exists on non-root cgroups.
+
+       Shows pressure stall information for IO. See
+       Documentation/accounting/psi.txt for details.
+
 
 Writeback
 ~~~~~~~~~
@@ -1857,10 +1879,8 @@ following two functions.
 
   wbc_init_bio(@wbc, @bio)
        Should be called for each bio carrying writeback data and
-       associates the bio with the inode's owner cgroup and the
-       corresponding request queue.  This must be called after
-       a queue (device) has been associated with the bio and
-       before submission.
+       associates the bio with the inode's owner cgroup.  Can be
+       called anytime between bio allocation and submission.
 
   wbc_account_io(@wbc, @page, @bytes)
        Should be called for each data segment being written out.
@@ -1879,7 +1899,7 @@ the configuration, the bio may be executed at a lower priority and if
 the writeback session is holding shared resources, e.g. a journal
 entry, may lead to priority inversion.  There is no one easy solution
 for the problem.  Filesystems can try to work around specific problem
-cases by skipping wbc_init_bio() or using bio_associate_create_blkg()
+cases by skipping wbc_init_bio() or using bio_associate_blkcg()
 directly.