[PATCH 06/13] cpuset: cleanup cpuset[_can]_attach()
From: Tejun Heo <tj@kernel.org>
Date: 2012-11-28 21:34:47
Also in:
linux-mm, lkml
Subsystem:
the rest · Maintainer:
Linus Torvalds
cpuset_can_attach() prepare global variables cpus_attach and
cpuset_attach_nodemask_{to|from} which are used by cpuset_attach().
There is no reason to prepare in cpuset_can_attach(). The same
information can be accessed from cpuset_attach().
Move the prepartion logic from cpuset_can_attach() to cpuset_attach()
and make the global variables static ones inside cpuset_attach().
While at it, convert cpus_attach to cpumask_t from cpumask_var_t.
There's no reason to mess with dynamic allocation on a static buffer.
Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/cpuset.c | 34 +++++++++++++---------------------
1 file changed, 13 insertions(+), 21 deletions(-)
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 5a52ed6..8bdd983 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c@@ -1395,15 +1395,6 @@ static int fmeter_getrate(struct fmeter *fmp) return val; } -/* - * Protected by cgroup_lock. The nodemasks must be stored globally because - * dynamically allocating them is not allowed in can_attach, and they must - * persist until attach. - */ -static cpumask_var_t cpus_attach; -static nodemask_t cpuset_attach_nodemask_from; -static nodemask_t cpuset_attach_nodemask_to; - /* Called by cgroups to determine if a cpuset is usable; cgroup_mutex held */ static int cpuset_can_attach(struct cgroup *cgrp, struct cgroup_taskset *tset) {
@@ -1430,19 +1421,15 @@ static int cpuset_can_attach(struct cgroup *cgrp, struct cgroup_taskset *tset) return ret; } - /* prepare for attach */ - if (cs == &top_cpuset) - cpumask_copy(cpus_attach, cpu_possible_mask); - else - guarantee_online_cpus(cs, cpus_attach); - - guarantee_online_mems(cs, &cpuset_attach_nodemask_to); - return 0; } static void cpuset_attach(struct cgroup *cgrp, struct cgroup_taskset *tset) { + /* static bufs protected by cgroup_mutex */ + static cpumask_t cpus_attach; + static nodemask_t cpuset_attach_nodemask_from; + static nodemask_t cpuset_attach_nodemask_to; struct mm_struct *mm; struct task_struct *task; struct task_struct *leader = cgroup_taskset_first(tset);
@@ -1450,12 +1437,20 @@ static void cpuset_attach(struct cgroup *cgrp, struct cgroup_taskset *tset) struct cpuset *cs = cgroup_cs(cgrp); struct cpuset *oldcs = cgroup_cs(oldcgrp); + /* prepare for attach */ + if (cs == &top_cpuset) + cpumask_copy(&cpus_attach, cpu_possible_mask); + else + guarantee_online_cpus(cs, &cpus_attach); + + guarantee_online_mems(cs, &cpuset_attach_nodemask_to); + cgroup_taskset_for_each(task, cgrp, tset) { /* * can_attach beforehand should guarantee that this doesn't * fail. TODO: have a better way to handle failure here */ - WARN_ON_ONCE(set_cpus_allowed_ptr(task, cpus_attach)); + WARN_ON_ONCE(set_cpus_allowed_ptr(task, &cpus_attach)); cpuset_change_task_nodemask(task, &cpuset_attach_nodemask_to); cpuset_update_task_spread_flag(cs, task);
@@ -1958,9 +1953,6 @@ int __init cpuset_init(void) if (err < 0) return err; - if (!alloc_cpumask_var(&cpus_attach, GFP_KERNEL)) - BUG(); - number_of_cpusets = 1; return 0; }
--
1.7.11.7
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