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SubjectRe: [PATCH v2 07/10] futex: use freezable blocking call
On Wed, 1 May 2013, Colin Cross wrote:

> Avoid waking up every thread sleeping in a futex_wait call during
> suspend and resume by calling a freezable blocking call. Previous
> patches modified the freezer to avoid sending wakeups to threads
> that are blocked in freezable blocking calls.
>
> This call was selected to be converted to a freezable call because
> it doesn't hold any locks or release any resources when interrupted
> that might be needed by another freezing task or a kernel driver
> during suspend, and is a common site where idle userspace tasks are
> blocked.
>
> Signed-off-by: Colin Cross <ccross@android.com>

Acked-by: Thomas Gleixner <tglx@linutronix.de>

> ---
> kernel/futex.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/futex.c b/kernel/futex.c
> index b26dcfc..d710fae 100644
> --- a/kernel/futex.c
> +++ b/kernel/futex.c
> @@ -61,6 +61,7 @@
> #include <linux/nsproxy.h>
> #include <linux/ptrace.h>
> #include <linux/sched/rt.h>
> +#include <linux/freezer.h>
>
> #include <asm/futex.h>
>
> @@ -1807,7 +1808,7 @@ static void futex_wait_queue_me(struct futex_hash_bucket *hb, struct futex_q *q,
> * is no timeout, or if it has yet to expire.
> */
> if (!timeout || timeout->task)
> - schedule();
> + freezable_schedule();
> }
> __set_current_state(TASK_RUNNING);
> }
> --
> 1.8.2.1
>
>


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