FROMLIST: binder: Use wake up hint for synchronous transactions.

(from https://patchwork.kernel.org/patch/9817747)

Use wake_up_interruptible_sync() to hint to the scheduler binder
transactions are synchronous wakeups. Disable preemption while waking
to avoid ping-ponging on the binder lock.

Change-Id: I041dd798f3d0c4c15aa461e4e6d71dc270e1ca86
Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Omprakash Dhyade <odhyade@codeaurora.org>

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 9105f416ce463d6180453ffb4f7f842aa0cc0c32..9ff1d15f7c3100ca4dca2705093be61d311b48c2 100644 (file)
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2200,8 +2200,12 @@ static void binder_transaction(struct binder_proc *proc,
        list_add_tail(&t->work.entry, target_list);
        tcomplete->type = BINDER_WORK_TRANSACTION_COMPLETE;
        list_add_tail(&tcomplete->entry, &thread->todo);
-       if (target_wait)
-               wake_up_interruptible(target_wait);
+       if (target_wait) {
+               if (reply || !(t->flags & TF_ONE_WAY))
+                       wake_up_interruptible_sync(target_wait);
+               else
+                       wake_up_interruptible(target_wait);
+       }
        return;
 
 err_translate_failed: