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| author | Prateek Sood <prsood@codeaurora.org> | 2017-11-15 19:50:15 +0530 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2017-11-27 08:48:10 -0800 |
| commit | 1599a185f0e6113be185b9fb809c621c73865829 (patch) | |
| tree | dd2f4646ce247a91b3b531c32f3331f354a024de /kernel | |
| parent | aa24163b2ee5c92120e32e99b5a93143a0f4258e (diff) | |
| download | linux-0-day-1599a185f0e6113be185b9fb809c621c73865829.tar.gz linux-0-day-1599a185f0e6113be185b9fb809c621c73865829.tar.xz | |
cpuset: Make cpuset hotplug synchronous
Convert cpuset_hotplug_workfn() into synchronous call for cpu hotplug
path. For memory hotplug path it still gets queued as a work item.
Since cpuset_hotplug_workfn() can be made synchronous for cpu hotplug
path, it is not required to wait for cpuset hotplug while thawing
processes.
Signed-off-by: Prateek Sood <prsood@codeaurora.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/cgroup/cpuset.c | 41 | ||||
| -rw-r--r-- | kernel/power/process.c | 2 | ||||
| -rw-r--r-- | kernel/sched/core.c | 1 |
3 files changed, 20 insertions, 24 deletions
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index cab5fd1ee7671..227bc25d951dd 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -2277,15 +2277,8 @@ retry: mutex_unlock(&cpuset_mutex); } -static bool force_rebuild; - -void cpuset_force_rebuild(void) -{ - force_rebuild = true; -} - /** - * cpuset_hotplug_workfn - handle CPU/memory hotunplug for a cpuset + * cpuset_hotplug - handle CPU/memory hotunplug for a cpuset * * This function is called after either CPU or memory configuration has * changed and updates cpuset accordingly. The top_cpuset is always @@ -2300,7 +2293,7 @@ void cpuset_force_rebuild(void) * Note that CPU offlining during suspend is ignored. We don't modify * cpusets across suspend/resume cycles at all. */ -static void cpuset_hotplug_workfn(struct work_struct *work) +static void cpuset_hotplug(bool use_cpu_hp_lock) { static cpumask_t new_cpus; static nodemask_t new_mems; @@ -2358,25 +2351,31 @@ static void cpuset_hotplug_workfn(struct work_struct *work) } /* rebuild sched domains if cpus_allowed has changed */ - if (cpus_updated || force_rebuild) { - force_rebuild = false; - rebuild_sched_domains(); + if (cpus_updated) { + if (use_cpu_hp_lock) + rebuild_sched_domains(); + else { + /* Acquiring cpu_hotplug_lock is not required. + * When cpuset_hotplug() is called in hotplug path, + * cpu_hotplug_lock is held by the hotplug context + * which is waiting for cpuhp_thread_fun to indicate + * completion of callback. + */ + mutex_lock(&cpuset_mutex); + rebuild_sched_domains_cpuslocked(); + mutex_unlock(&cpuset_mutex); + } } } -void cpuset_update_active_cpus(void) +static void cpuset_hotplug_workfn(struct work_struct *work) { - /* - * We're inside cpu hotplug critical region which usually nests - * inside cgroup synchronization. Bounce actual hotplug processing - * to a work item to avoid reverse locking order. - */ - schedule_work(&cpuset_hotplug_work); + cpuset_hotplug(true); } -void cpuset_wait_for_hotplug(void) +void cpuset_update_active_cpus(void) { - flush_work(&cpuset_hotplug_work); + cpuset_hotplug(false); } /* diff --git a/kernel/power/process.c b/kernel/power/process.c index 7381d49a44db5..c326d7235c5f0 100644 --- a/kernel/power/process.c +++ b/kernel/power/process.c @@ -204,8 +204,6 @@ void thaw_processes(void) __usermodehelper_set_disable_depth(UMH_FREEZING); thaw_workqueues(); - cpuset_wait_for_hotplug(); - read_lock(&tasklist_lock); for_each_process_thread(g, p) { /* No other threads should have PF_SUSPEND_TASK set */ diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 75554f366fd3a..88b3450b29abf 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5624,7 +5624,6 @@ static void cpuset_cpu_active(void) * restore the original sched domains by considering the * cpuset configurations. */ - cpuset_force_rebuild(); } cpuset_update_active_cpus(); } |