cgroup/cpuset: Expose cpuset.cpus.isolated

The root-only cpuset.cpus.isolated control file shows the current set
of isolated CPUs in isolated partitions. This control file is currently
exposed only with the cgroup_debug boot command line option which also
adds the ".__DEBUG__." prefix. This is actually a useful control file if
users want to find out which CPUs are currently in an isolated state by
the cpuset controller. Remove CFTYPE_DEBUG flag for this control file and
make it available by default without any prefix.

The test_cpuset_prs.sh test script and the cgroup-v2.rst documentation
file are also updated accordingly. Minor code change is also made in
test_cpuset_prs.sh to avoid false test failure when running on debug
kernel.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index cf5651a11df859078c81cb6bc5949dd642f61615..30f6ff2eba47f960440aa9af8c55c8c00b6956b9 100644 (file)
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -2316,6 +2316,13 @@ Cpuset Interface Files
        treated to have an implicit value of "cpuset.cpus" in the
        formation of local partition.
 
+  cpuset.cpus.isolated
+       A read-only and root cgroup only multiple values file.
+
+       This file shows the set of all isolated CPUs used in existing
+       isolated partitions. It will be empty if no isolated partition
+       is created.
+
   cpuset.cpus.partition
        A read-write single value file which exists on non-root
        cpuset-enabled cgroups.  This flag is owned by the parent cgroup

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 1bad4007ff4b58e5a7ec73314f58dcee4437b2d6..2a16df86c55c5adf6d840c951f513d2badc694f8 100644 (file)
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -3974,7 +3974,7 @@ static struct cftype dfl_files[] = {
                .name = "cpus.isolated",
                .seq_show = cpuset_common_seq_show,
                .private = FILE_ISOLATED_CPULIST,
-               .flags = CFTYPE_ONLY_ON_ROOT | CFTYPE_DEBUG,
+               .flags = CFTYPE_ONLY_ON_ROOT,
        },
 
        { }     /* terminate */

diff --git a/tools/testing/selftests/cgroup/test_cpuset_prs.sh b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
index 7b7c4c2b6d85650a3ce726534fe2e7e0aea5f0bb..b5eb1be2248c24e6b7cad9f45c4fd0247e2ff19f 100755 (executable)
--- a/tools/testing/selftests/cgroup/test_cpuset_prs.sh
+++ b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
@@ -508,7 +508,7 @@ dump_states()
                XECPUS=$DIR/cpuset.cpus.exclusive.effective
                PRS=$DIR/cpuset.cpus.partition
                PCPUS=$DIR/.__DEBUG__.cpuset.cpus.subpartitions
-               ISCPUS=$DIR/.__DEBUG__.cpuset.cpus.isolated
+               ISCPUS=$DIR/cpuset.cpus.isolated
                [[ -e $CPUS   ]] && echo "$CPUS: $(cat $CPUS)"
                [[ -e $XCPUS  ]] && echo "$XCPUS: $(cat $XCPUS)"
                [[ -e $ECPUS  ]] && echo "$ECPUS: $(cat $ECPUS)"
@@ -593,17 +593,17 @@ check_cgroup_states()
 
 #
 # Get isolated (including offline) CPUs by looking at
-# /sys/kernel/debug/sched/domains and *cpuset.cpus.isolated control file,
+# /sys/kernel/debug/sched/domains and cpuset.cpus.isolated control file,
 # if available, and compare that with the expected value.
 #
 # Note that isolated CPUs from the sched/domains context include offline
 # CPUs as well as CPUs in non-isolated 1-CPU partition. Those CPUs may
-# not be included in the *cpuset.cpus.isolated control file which contains
+# not be included in the cpuset.cpus.isolated control file which contains
 # only CPUs in isolated partitions.
 #
 # $1 - expected isolated cpu list(s) <isolcpus1>{,<isolcpus2>}
 # <isolcpus1> - expected sched/domains value
-# <isolcpus2> - *cpuset.cpus.isolated value = <isolcpus1> if not defined
+# <isolcpus2> - cpuset.cpus.isolated value = <isolcpus1> if not defined
 #
 check_isolcpus()
 {
@@ -611,7 +611,7 @@ check_isolcpus()
        ISOLCPUS=
        LASTISOLCPU=
        SCHED_DOMAINS=/sys/kernel/debug/sched/domains
-       ISCPUS=${CGROUP2}/.__DEBUG__.cpuset.cpus.isolated
+       ISCPUS=${CGROUP2}/cpuset.cpus.isolated
        if [[ $EXPECT_VAL = . ]]
        then
                EXPECT_VAL=
@@ -692,14 +692,18 @@ test_fail()
 null_isolcpus_check()
 {
        [[ $VERBOSE -gt 0 ]] || return 0
-       pause 0.02
-       check_isolcpus "."
-       if [[ $? -ne 0 ]]
-       then
-               echo "Unexpected isolated CPUs: $ISOLCPUS"
-               dump_states
-               exit 1
-       fi
+       # Retry a few times before printing error
+       RETRY=0
+       while [[ $RETRY -lt 5 ]]
+       do
+               pause 0.01
+               check_isolcpus "."
+               [[ $? -eq 0 ]] && return 0
+               ((RETRY++))
+       done
+       echo "Unexpected isolated CPUs: $ISOLCPUS"
+       dump_states
+       exit 1
 }
 
 #
@@ -776,7 +780,7 @@ run_state_test()
                #
                NEWLIST=$(cat cpuset.cpus.effective)
                RETRY=0
-               while [[ $NEWLIST != $CPULIST && $RETRY -lt 5 ]]
+               while [[ $NEWLIST != $CPULIST && $RETRY -lt 8 ]]
                do
                        # Wait a bit longer & recheck a few times
                        pause 0.01