aboutsummaryrefslogtreecommitdiffstats
path: root/kernel
diff options
context:
space:
mode:
authorLi Zefan <lizf@cn.fujitsu.com>2008-09-13 05:33:08 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-09-13 17:41:50 -0400
commit4e74339af6a59c061cf02f1ac497766bca1de19a (patch)
tree0903456d2aced7e2e9534b3b3d1c5f58e1056b53 /kernel
parentdea420ce0e2973e8ef1fd11fde6804c8d03a82ad (diff)
cpuset: avoid changing cpuset's cpus when -errno returned
After the patch: commit 0b2f630a28d53b5a2082a5275bc3334b10373508 Author: Miao Xie <miaox@cn.fujitsu.com> Date: Fri Jul 25 01:47:21 2008 -0700 cpusets: restructure the function update_cpumask() and update_nodemask() It might happen that 'echo 0 > /cpuset/sub/cpus' returned failure but 'cpus' has been changed, because cpus was changed before calling heap_init() which may return -ENOMEM. This patch restores the orginal behavior. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Cc: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/cpuset.c37
1 files changed, 15 insertions, 22 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index f227bc172690..827cd9adccb2 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -843,37 +843,25 @@ static void cpuset_change_cpumask(struct task_struct *tsk,
843/** 843/**
844 * update_tasks_cpumask - Update the cpumasks of tasks in the cpuset. 844 * update_tasks_cpumask - Update the cpumasks of tasks in the cpuset.
845 * @cs: the cpuset in which each task's cpus_allowed mask needs to be changed 845 * @cs: the cpuset in which each task's cpus_allowed mask needs to be changed
846 * @heap: if NULL, defer allocating heap memory to cgroup_scan_tasks()
846 * 847 *
847 * Called with cgroup_mutex held 848 * Called with cgroup_mutex held
848 * 849 *
849 * The cgroup_scan_tasks() function will scan all the tasks in a cgroup, 850 * The cgroup_scan_tasks() function will scan all the tasks in a cgroup,
850 * calling callback functions for each. 851 * calling callback functions for each.
851 * 852 *
852 * Return 0 if successful, -errno if not. 853 * No return value. It's guaranteed that cgroup_scan_tasks() always returns 0
854 * if @heap != NULL.
853 */ 855 */
854static int update_tasks_cpumask(struct cpuset *cs) 856static void update_tasks_cpumask(struct cpuset *cs, struct ptr_heap *heap)
855{ 857{
856 struct cgroup_scanner scan; 858 struct cgroup_scanner scan;
857 struct ptr_heap heap;
858 int retval;
859
860 /*
861 * cgroup_scan_tasks() will initialize heap->gt for us.
862 * heap_init() is still needed here for we should not change
863 * cs->cpus_allowed when heap_init() fails.
864 */
865 retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL);
866 if (retval)
867 return retval;
868 859
869 scan.cg = cs->css.cgroup; 860 scan.cg = cs->css.cgroup;
870 scan.test_task = cpuset_test_cpumask; 861 scan.test_task = cpuset_test_cpumask;
871 scan.process_task = cpuset_change_cpumask; 862 scan.process_task = cpuset_change_cpumask;
872 scan.heap = &heap; 863 scan.heap = heap;
873 retval = cgroup_scan_tasks(&scan); 864 cgroup_scan_tasks(&scan);
874
875 heap_free(&heap);
876 return retval;
877} 865}
878 866
879/** 867/**
@@ -883,6 +871,7 @@ static int update_tasks_cpumask(struct cpuset *cs)
883 */ 871 */
884static int update_cpumask(struct cpuset *cs, const char *buf) 872static int update_cpumask(struct cpuset *cs, const char *buf)
885{ 873{
874 struct ptr_heap heap;
886 struct cpuset trialcs; 875 struct cpuset trialcs;
887 int retval; 876 int retval;
888 int is_load_balanced; 877 int is_load_balanced;
@@ -917,6 +906,10 @@ static int update_cpumask(struct cpuset *cs, const char *buf)
917 if (cpus_equal(cs->cpus_allowed, trialcs.cpus_allowed)) 906 if (cpus_equal(cs->cpus_allowed, trialcs.cpus_allowed))
918 return 0; 907 return 0;
919 908
909 retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL);
910 if (retval)
911 return retval;
912
920 is_load_balanced = is_sched_load_balance(&trialcs); 913 is_load_balanced = is_sched_load_balance(&trialcs);
921 914
922 mutex_lock(&callback_mutex); 915 mutex_lock(&callback_mutex);
@@ -927,9 +920,9 @@ static int update_cpumask(struct cpuset *cs, const char *buf)
927 * Scan tasks in the cpuset, and update the cpumasks of any 920 * Scan tasks in the cpuset, and update the cpumasks of any
928 * that need an update. 921 * that need an update.
929 */ 922 */
930 retval = update_tasks_cpumask(cs); 923 update_tasks_cpumask(cs, &heap);
931 if (retval < 0) 924
932 return retval; 925 heap_free(&heap);
933 926
934 if (is_load_balanced) 927 if (is_load_balanced)
935 async_rebuild_sched_domains(); 928 async_rebuild_sched_domains();
@@ -1965,7 +1958,7 @@ static void scan_for_empty_cpusets(const struct cpuset *root)
1965 nodes_empty(cp->mems_allowed)) 1958 nodes_empty(cp->mems_allowed))
1966 remove_tasks_in_empty_cpuset(cp); 1959 remove_tasks_in_empty_cpuset(cp);
1967 else { 1960 else {
1968 update_tasks_cpumask(cp); 1961 update_tasks_cpumask(cp, NULL);
1969 update_tasks_nodemask(cp, &oldmems); 1962 update_tasks_nodemask(cp, &oldmems);
1970 } 1963 }
1971 } 1964 }