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Subject[PATCH v2 2/4] PM/Freezer: Make thaw_processes() thaw only userspace tasks
Date
Currently the situation is:

freeze_processes() - freezes only userspace tasks
freeze_kernel_threads() - freezes only kernel threads
thaw_kernel_threads() - thaws only kernel threads
thaw_processes() - thaws *everything* (both userspace tasks and kernel threads)

The point that thaw_processes() thaws everything is rather unintuitive
and can lead to bugs. So, modify thaw_processes() so that it thaws only
userspace processes. This way we can also have more control over what
exactly gets thawed in different situations.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
---

kernel/power/process.c | 9 ++++-----
1 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/kernel/power/process.c b/kernel/power/process.c
index 3734fb9..8ae6c4b 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -116,7 +116,8 @@ static int try_to_freeze_tasks(bool user_only)
/**
* freeze_processes - Signal user space processes to enter the refrigerator.
*
- * On success, returns 0. On failure, -errno and system is fully thawed.
+ * On success, returns 0. On failure, -errno and all user space processes
+ * are thawed.
*/
int freeze_processes(void)
{
@@ -170,17 +171,15 @@ void thaw_processes(void)
if (pm_freezing)
atomic_dec(&system_freezing_cnt);
pm_freezing = false;
- pm_nosig_freezing = false;

oom_killer_enable();

printk("Restarting tasks ... ");

- thaw_workqueues();
-
read_lock(&tasklist_lock);
do_each_thread(g, p) {
- __thaw_task(p);
+ if (!(p->flags & (PF_KTHREAD | PF_WQ_WORKER)))
+ __thaw_task(p);
} while_each_thread(g, p);
read_unlock(&tasklist_lock);



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