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| author | Tejun Heo <tj@kernel.org> | 2017-05-24 12:03:48 -0400 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2017-05-24 12:43:30 -0400 |
| commit | 41c25707d21716826e3c1f60967f5550610ec1c9 (patch) | |
| tree | 41092221c68b8ec835d5a00e9d38440e67d613b9 /kernel/cgroup/cpuset.c | |
| parent | 33c35aa4817864e056fd772230b0c6b552e36ea2 (diff) | |
| download | lwn-41c25707d21716826e3c1f60967f5550610ec1c9.tar.gz lwn-41c25707d21716826e3c1f60967f5550610ec1c9.zip | |
cpuset: consider dying css as offline
In most cases, a cgroup controller don't care about the liftimes of
cgroups. For the controller, a css becomes online when ->css_online()
is called on it and offline when ->css_offline() is called.
However, cpuset is special in that the user interface it exposes cares
whether certain cgroups exist or not. Combined with the RCU delay
between cgroup removal and css offlining, this can lead to user
visible behavior oddities where operations which should succeed after
cgroup removals fail for some time period. The effects of cgroup
removals are delayed when seen from userland.
This patch adds css_is_dying() which tests whether offline is pending
and updates is_cpuset_online() so that the function returns false also
while offline is pending. This gets rid of the userland visible
delays.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Link: http://lkml.kernel.org/r/327ca1f5-7957-fbb9-9e5f-9ba149d40ba2@oracle.com
Cc: stable@vger.kernel.org
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/cgroup/cpuset.c')
| -rw-r--r-- | kernel/cgroup/cpuset.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index f6501f4f6040..ae643412948a 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -176,9 +176,9 @@ typedef enum { } cpuset_flagbits_t; /* convenient tests for these bits */ -static inline bool is_cpuset_online(const struct cpuset *cs) +static inline bool is_cpuset_online(struct cpuset *cs) { - return test_bit(CS_ONLINE, &cs->flags); + return test_bit(CS_ONLINE, &cs->flags) && !css_is_dying(&cs->css); } static inline int is_cpu_exclusive(const struct cpuset *cs) |