From b450129554213a4d4c5932f8a293646c029e1b0a Mon Sep 17 00:00:00 2001 From: Paul Jackson Date: Thu, 7 Feb 2008 00:14:47 -0800 Subject: [PATCH] hotplug cpu move tasks in empty cpusets - refinements - Narrow the scope of callback_mutex in scan_for_empty_cpusets(). - Avoid rewriting the cpus, mems of cpusets except when it is likely that we'll be changing them. - Have remove_tasks_in_empty_cpuset() also check for empty mems. Signed-off-by: Paul Jackson Acked-by: Cliff Wickman Cc: David Rientjes Cc: Paul Menage Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/cpuset.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 6868c1e7891..67b2bfe2781 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -1709,7 +1709,8 @@ static void remove_tasks_in_empty_cpuset(struct cpuset *cs) * has online cpus, so can't be empty). */ parent = cs->parent; - while (cpus_empty(parent->cpus_allowed)) + while (cpus_empty(parent->cpus_allowed) || + nodes_empty(parent->mems_allowed)) parent = parent->parent; move_member_tasks_to_cpuset(cs, parent); @@ -1741,7 +1742,6 @@ static void scan_for_empty_cpusets(const struct cpuset *root) list_add_tail((struct list_head *)&root->stack_list, &queue); - mutex_lock(&callback_mutex); while (!list_empty(&queue)) { cp = container_of(queue.next, struct cpuset, stack_list); list_del(queue.next); @@ -1750,19 +1750,24 @@ static void scan_for_empty_cpusets(const struct cpuset *root) list_add_tail(&child->stack_list, &queue); } cont = cp->css.cgroup; + + /* Continue past cpusets with all cpus, mems online */ + if (cpus_subset(cp->cpus_allowed, cpu_online_map) && + nodes_subset(cp->mems_allowed, node_states[N_HIGH_MEMORY])) + continue; + /* Remove offline cpus and mems from this cpuset. */ + mutex_lock(&callback_mutex); cpus_and(cp->cpus_allowed, cp->cpus_allowed, cpu_online_map); nodes_and(cp->mems_allowed, cp->mems_allowed, node_states[N_HIGH_MEMORY]); + mutex_unlock(&callback_mutex); + + /* Move tasks from the empty cpuset to a parent */ if (cpus_empty(cp->cpus_allowed) || - nodes_empty(cp->mems_allowed)) { - /* Move tasks from the empty cpuset to a parent */ - mutex_unlock(&callback_mutex); + nodes_empty(cp->mems_allowed)) remove_tasks_in_empty_cpuset(cp); - mutex_lock(&callback_mutex); - } } - mutex_unlock(&callback_mutex); } /*