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From:   Waiman Long <longman@redhat.com>
To:     Tejun Heo <tj@kernel.org>, Li Zefan <lizefan@huawei.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>
Cc:     cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-doc@vger.kernel.org, kernel-team@fb.com, pjt@google.com,
        luto@amacapital.net, Mike Galbraith <efault@gmx.de>,
        torvalds@linux-foundation.org, Roman Gushchin <guro@fb.com>,
        Juri Lelli <juri.lelli@redhat.com>,
        Waiman Long <longman@redhat.com>
Subject: [PATCH v8 5/6] cpuset: Expose cpus.effective and mems.effective on cgroup v2 root
Date:   Thu, 17 May 2018 16:55:44 -0400
Message-Id: <1526590545-3350-6-git-send-email-longman@redhat.com>
In-Reply-To: <1526590545-3350-1-git-send-email-longman@redhat.com>
References: <1526590545-3350-1-git-send-email-longman@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
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Because of the fact that setting the "cpuset.sched.domain" in a direct
child of root can remove CPUs from the root's effective CPU list, it
makes sense to know what CPUs are left in the root cgroup for scheduling
purpose. So the "cpuset.cpus.effective" control file is now exposed in
the v2 cgroup root.

For consistency, the "cpuset.mems.effective" control file is exposed
as well.

Signed-off-by: Waiman Long <longman@redhat.com>
---
 Documentation/cgroup-v2.txt | 4 ++--
 kernel/cgroup/cpuset.c      | 2 --
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt
index 071b634d..8739b10 100644
--- a/Documentation/cgroup-v2.txt
+++ b/Documentation/cgroup-v2.txt
@@ -1474,7 +1474,7 @@ Cpuset Interface Files
 	and won't be affected by any CPU hotplug events.
 
   cpuset.cpus.effective
-	A read-only multiple values file which exists on non-root
+	A read-only multiple values file which exists on all
 	cpuset-enabled cgroups.
 
 	It lists the onlined CPUs that are actually allowed to be
@@ -1504,7 +1504,7 @@ Cpuset Interface Files
 	and won't be affected by any memory nodes hotplug events.
 
   cpuset.mems.effective
-	A read-only multiple values file which exists on non-root
+	A read-only multiple values file which exists on all
 	cpuset-enabled cgroups.
 
 	It lists the onlined memory nodes that are actually allowed to
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 0e75f83..fb8aa82b 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -2203,14 +2203,12 @@ static s64 cpuset_read_s64(struct cgroup_subsys_state *css, struct cftype *cft)
 		.name = "cpus.effective",
 		.seq_show = cpuset_common_seq_show,
 		.private = FILE_EFFECTIVE_CPULIST,
-		.flags = CFTYPE_NOT_ON_ROOT,
 	},
 
 	{
 		.name = "mems.effective",
 		.seq_show = cpuset_common_seq_show,
 		.private = FILE_EFFECTIVE_MEMLIST,
-		.flags = CFTYPE_NOT_ON_ROOT,
 	},
 
 	{
-- 
1.8.3.1