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authorVarun Wadekar <vwadekar@nvidia.com>2012-01-16 15:32:21 +0530
committerVarun Wadekar <vwadekar@nvidia.com>2012-01-16 15:32:21 +0530
commit7919e929aa227048738e14df6bcbad3ee4458443 (patch)
tree0c38267369fa636d7435bf22af39e3783a24ef62 /kernel
parentfcbd75c6b179b717b074d0cb7490e42ae728fb2d (diff)
parent93dad393c796013cb6371be63d7af600c5e36c2c (diff)
Merge branch 'linux-3.1.y' into android-tegra-nv-3.1
Linux 3.1.9 Conflicts: Makefile Change-Id: I22227ab33ba7ddaba8e6fe049393c58a83d73648 Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/cgroup.c6
-rw-r--r--kernel/cpu.c74
2 files changed, 77 insertions, 3 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 225f47478f34..54a36fe288f0 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1178,10 +1178,10 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
/*
* If the 'all' option was specified select all the subsystems,
- * otherwise 'all, 'none' and a subsystem name options were not
- * specified, let's default to 'all'
+ * otherwise if 'none', 'name=' and a subsystem name options
+ * were not specified, let's default to 'all'
*/
- if (all_ss || (!all_ss && !one_ss && !opts->none)) {
+ if (all_ss || (!one_ss && !opts->none && !opts->name)) {
for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
struct cgroup_subsys *ss = subsys[i];
if (ss == NULL)
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 404770761a4e..eae3d9b39574 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -15,6 +15,7 @@
#include <linux/stop_machine.h>
#include <linux/mutex.h>
#include <linux/gfp.h>
+#include <linux/suspend.h>
#ifdef CONFIG_SMP
/* Serializes the updates to cpu_online_mask, cpu_present_mask */
@@ -476,6 +477,79 @@ static int alloc_frozen_cpus(void)
return 0;
}
core_initcall(alloc_frozen_cpus);
+
+/*
+ * Prevent regular CPU hotplug from racing with the freezer, by disabling CPU
+ * hotplug when tasks are about to be frozen. Also, don't allow the freezer
+ * to continue until any currently running CPU hotplug operation gets
+ * completed.
+ * To modify the 'cpu_hotplug_disabled' flag, we need to acquire the
+ * 'cpu_add_remove_lock'. And this same lock is also taken by the regular
+ * CPU hotplug path and released only after it is complete. Thus, we
+ * (and hence the freezer) will block here until any currently running CPU
+ * hotplug operation gets completed.
+ */
+void cpu_hotplug_disable_before_freeze(void)
+{
+ cpu_maps_update_begin();
+ cpu_hotplug_disabled = 1;
+ cpu_maps_update_done();
+}
+
+
+/*
+ * When tasks have been thawed, re-enable regular CPU hotplug (which had been
+ * disabled while beginning to freeze tasks).
+ */
+void cpu_hotplug_enable_after_thaw(void)
+{
+ cpu_maps_update_begin();
+ cpu_hotplug_disabled = 0;
+ cpu_maps_update_done();
+}
+
+/*
+ * When callbacks for CPU hotplug notifications are being executed, we must
+ * ensure that the state of the system with respect to the tasks being frozen
+ * or not, as reported by the notification, remains unchanged *throughout the
+ * duration* of the execution of the callbacks.
+ * Hence we need to prevent the freezer from racing with regular CPU hotplug.
+ *
+ * This synchronization is implemented by mutually excluding regular CPU
+ * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/
+ * Hibernate notifications.
+ */
+static int
+cpu_hotplug_pm_callback(struct notifier_block *nb,
+ unsigned long action, void *ptr)
+{
+ switch (action) {
+
+ case PM_SUSPEND_PREPARE:
+ case PM_HIBERNATION_PREPARE:
+ cpu_hotplug_disable_before_freeze();
+ break;
+
+ case PM_POST_SUSPEND:
+ case PM_POST_HIBERNATION:
+ cpu_hotplug_enable_after_thaw();
+ break;
+
+ default:
+ return NOTIFY_DONE;
+ }
+
+ return NOTIFY_OK;
+}
+
+
+int cpu_hotplug_pm_sync_init(void)
+{
+ pm_notifier(cpu_hotplug_pm_callback, 0);
+ return 0;
+}
+core_initcall(cpu_hotplug_pm_sync_init);
+
#endif /* CONFIG_PM_SLEEP_SMP */
/**