| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 69/84] binder: Use wake up hint for synchronous transactions. | Date | Mon, 28 Aug 2017 10:05:34 +0200 |
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4.9-stable review patch. If anyone has any objections, please let me know.
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From: Riley Andrews <riandrews@google.com>
commit 00b40d613352c623aaae88a44e5ded7c912909d7 upstream.
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.
Signed-off-by: Todd Kjos <tkjos@google.com> Signed-off-by: Omprakash Dhyade <odhyade@codeaurora.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/android/binder.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -1724,8 +1724,12 @@ static void binder_transaction(struct bi 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_get_unused_fd_failed:
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