Re: [PATCH v2 11/14] csky/thread_info: Introduce TIF_NOTIFY_IPI flag

Guo Ren
2024-06-15T17:13:52Z

On Fri, Jun 14, 2024 at 2:21 AM K Prateek Nayak <kprateek.nayak@amd.com> wrote:
>
> Add support for TIF_NOTIFY_IPI on C-SKY. With TIF_NOTIFY_IPI, a sender
> sending an IPI to an idle CPU in TIF_POLLING mode will set the
> TIF_NOTIFY_IPI flag in the target's idle tasks's thread_info to pull the
> CPU out of idle, as opposed to setting TIF_NEED_RESCHED previously. This
> avoids spurious calls to schedule_idle() in cases where an IPI does not
> necessarily wake up a task on the idle CPU.
>
> Cc: Guo Ren <guoren@kernel.org>
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Juri Lelli <juri.lelli@redhat.com>
> Cc: Vincent Guittot <vincent.guittot@linaro.org>
> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: Ben Segall <bsegall@google.com>
> Cc: Mel Gorman <mgorman@suse.de>
> Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
> Cc: Valentin Schneider <vschneid@redhat.com>
> Cc: K Prateek Nayak <kprateek.nayak@amd.com>
> Cc: linux-csky@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Cc: linux-pm@vger.kernel.org
> Acked-by: Guo Ren <guoren@kernel.org>
> Signed-off-by: K Prateek Nayak <kprateek.nayak@amd.com>
> ---
> v1..v2:
> o Collected the ack. Thank you :)
> ---
> arch/csky/include/asm/thread_info.h | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/csky/include/asm/thread_info.h b/arch/csky/include/asm/thread_info.h
> index b5ed788f0c68..9bc7a037c476 100644
> --- a/arch/csky/include/asm/thread_info.h
> +++ b/arch/csky/include/asm/thread_info.h
> @@ -61,6 +61,7 @@ static inline struct thread_info *current_thread_info(void)
> #define TIF_SYSCALL_TRACEPOINT 5 /* syscall tracepoint instrumentation */
> #define TIF_SYSCALL_AUDIT 6 /* syscall auditing */
> #define TIF_NOTIFY_SIGNAL 7 /* signal notifications exist */
> +#define TIF_NOTIFY_IPI 8 /* Pending IPI on TIF_POLLLING idle CPU */
> #define TIF_POLLING_NRFLAG 16 /* poll_idle() is TIF_NEED_RESCHED */
> #define TIF_MEMDIE 18 /* is terminating due to OOM killer */
> #define TIF_RESTORE_SIGMASK 20 /* restore signal mask in do_signal() */
> @@ -73,6 +74,7 @@ static inline struct thread_info *current_thread_info(void)
> #define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
> #define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
> #define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL)
> +#define _TIF_NOTIFY_IPI (1 << TIF_NOTIFY_IPI)
Acked-by: Guo Ren <guoren@kernel.org>

> #define _TIF_UPROBE (1 << TIF_UPROBE)
> #define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
> #define _TIF_MEMDIE (1 << TIF_MEMDIE)
> --
> 2.34.1
>

--
Best Regards
Guo Ren