From be4c9dd7aee5ecf3e748da68c27b38bdca70d444 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Wed, 9 Jul 2014 16:49:04 +0800 Subject: [PATCH] cpuset: enable onlined cpu/node in effective masks Firstly offline cpu1: # echo 0-1 > cpuset.cpus # echo 0 > /sys/devices/system/cpu/cpu1/online # cat cpuset.cpus 0-1 # cat cpuset.effective_cpus 0 Then online it: # echo 1 > /sys/devices/system/cpu/cpu1/online # cat cpuset.cpus 0-1 # cat cpuset.effective_cpus 0-1 And cpuset will bring it back to the effective mask. The implementation is quite straightforward. Instead of calculating the offlined cpus/mems and do updates, we just set the new effective_mask to online_mask & congifured_mask. This is a behavior change for default hierarchy, so legacy hierarchy won't be affected. v2: - make refactoring of cpuset_hotplug_update_tasks() as seperate patch, suggested by Tejun. - make hotplug_update_tasks_insane() use @new_cpus and @new_mems as hotplug_update_tasks_sane() does. Signed-off-by: Li Zefan Signed-off-by: Tejun Heo --- kernel/cpuset.c | 65 +++++++++++++++++++++++++++---------------------- 1 file changed, 36 insertions(+), 29 deletions(-) diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 41822e2027c1..c47cb940712e 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -2080,26 +2080,27 @@ static void remove_tasks_in_empty_cpuset(struct cpuset *cs) } } -static void hotplug_update_tasks_legacy(struct cpuset *cs, - struct cpumask *off_cpus, - nodemask_t *off_mems) +static void +hotplug_update_tasks_legacy(struct cpuset *cs, + struct cpumask *new_cpus, nodemask_t *new_mems, + bool cpus_updated, bool mems_updated) { bool is_empty; mutex_lock(&callback_mutex); - cpumask_andnot(cs->cpus_allowed, cs->cpus_allowed, off_cpus); - cpumask_andnot(cs->effective_cpus, cs->effective_cpus, off_cpus); - nodes_andnot(cs->mems_allowed, cs->mems_allowed, *off_mems); - nodes_andnot(cs->effective_mems, cs->effective_mems, *off_mems); + cpumask_copy(cs->cpus_allowed, new_cpus); + cpumask_copy(cs->effective_cpus, new_cpus); + cs->mems_allowed = *new_mems; + cs->effective_mems = *new_mems; mutex_unlock(&callback_mutex); /* * Don't call update_tasks_cpumask() if the cpuset becomes empty, * as the tasks will be migratecd to an ancestor. */ - if (!cpumask_empty(off_cpus) && !cpumask_empty(cs->cpus_allowed)) + if (cpus_updated && !cpumask_empty(cs->cpus_allowed)) update_tasks_cpumask(cs); - if (!nodes_empty(*off_mems) && !nodes_empty(cs->mems_allowed)) + if (mems_updated && !nodes_empty(cs->mems_allowed)) update_tasks_nodemask(cs); is_empty = cpumask_empty(cs->cpus_allowed) || @@ -2118,24 +2119,24 @@ static void hotplug_update_tasks_legacy(struct cpuset *cs, mutex_lock(&cpuset_mutex); } -static void hotplug_update_tasks(struct cpuset *cs, - struct cpumask *off_cpus, - nodemask_t *off_mems) +static void +hotplug_update_tasks(struct cpuset *cs, + struct cpumask *new_cpus, nodemask_t *new_mems, + bool cpus_updated, bool mems_updated) { - mutex_lock(&callback_mutex); - cpumask_andnot(cs->effective_cpus, cs->effective_cpus, off_cpus); - if (cpumask_empty(cs->effective_cpus)) - cpumask_copy(cs->effective_cpus, - parent_cs(cs)->effective_cpus); + if (cpumask_empty(new_cpus)) + cpumask_copy(new_cpus, parent_cs(cs)->effective_cpus); + if (nodes_empty(*new_mems)) + *new_mems = parent_cs(cs)->effective_mems; - nodes_andnot(cs->effective_mems, cs->effective_mems, *off_mems); - if (nodes_empty(cs->effective_mems)) - cs->effective_mems = parent_cs(cs)->effective_mems; + mutex_lock(&callback_mutex); + cpumask_copy(cs->effective_cpus, new_cpus); + cs->effective_mems = *new_mems; mutex_unlock(&callback_mutex); - if (!cpumask_empty(off_cpus)) + if (cpus_updated) update_tasks_cpumask(cs); - if (!nodes_empty(*off_mems)) + if (mems_updated) update_tasks_nodemask(cs); } @@ -2149,8 +2150,10 @@ static void hotplug_update_tasks(struct cpuset *cs, */ static void cpuset_hotplug_update_tasks(struct cpuset *cs) { - static cpumask_t off_cpus; - static nodemask_t off_mems; + static cpumask_t new_cpus; + static nodemask_t new_mems; + bool cpus_updated; + bool mems_updated; retry: wait_event(cpuset_attach_wq, cs->attach_in_progress == 0); @@ -2165,14 +2168,18 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs) goto retry; } - cpumask_andnot(&off_cpus, cs->effective_cpus, - top_cpuset.effective_cpus); - nodes_andnot(off_mems, cs->effective_mems, top_cpuset.effective_mems); + cpumask_and(&new_cpus, cs->cpus_allowed, parent_cs(cs)->effective_cpus); + nodes_and(new_mems, cs->mems_allowed, parent_cs(cs)->effective_mems); + + cpus_updated = !cpumask_equal(&new_cpus, cs->effective_cpus); + mems_updated = !nodes_equal(new_mems, cs->effective_mems); if (cgroup_on_dfl(cs->css.cgroup)) - hotplug_update_tasks(cs, &off_cpus, &off_mems); + hotplug_update_tasks(cs, &new_cpus, &new_mems, + cpus_updated, mems_updated); else - hotplug_update_tasks_legacy(cs, &off_cpus, &off_mems); + hotplug_update_tasks_legacy(cs, &new_cpus, &new_mems, + cpus_updated, mems_updated); mutex_unlock(&cpuset_mutex); }