[PATCH v2 07/14] openrisc/thread_info: Introduce TIF_NOTIFY_IPI flag

K Prateek Nayak
2024-06-13T18:20:17Z

Add support for TIF_NOTIFY_IPI on OpenRISC. 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: Jonas Bonn <jonas@southpole.se>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Stafford Horne <shorne@gmail.com>
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-openrisc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Signed-off-by: K Prateek Nayak <kprateek.nayak@amd.com>
---
v1..v2:
o No changes.
---
arch/openrisc/include/asm/thread_info.h | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/openrisc/include/asm/thread_info.h b/arch/openrisc/include/asm/thread_info.h
index 4af3049c34c2..6a386703bc43 100644
--- a/arch/openrisc/include/asm/thread_info.h
+++ b/arch/openrisc/include/asm/thread_info.h
@@ -92,6 +92,7 @@ register struct thread_info *current_thread_info_reg asm("r10");
* mode
*/
#define TIF_NOTIFY_SIGNAL 5 /* signal notifications exist */
+#define TIF_NOTIFY_IPI 6 /* Pending IPI on TIF_POLLLING idle CPU */
#define TIF_SYSCALL_TRACEPOINT 8 /* for ftrace syscall instrumentation */
#define TIF_RESTORE_SIGMASK 9
#define TIF_POLLING_NRFLAG 16 /* true if poll_idle() is polling * TIF_NEED_RESCHED
@@ -104,6 +105,7 @@ register struct thread_info *current_thread_info_reg asm("r10");
#define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
#define _TIF_SINGLESTEP (1<<TIF_SINGLESTEP)
#define _TIF_NOTIFY_SIGNAL (1<<TIF_NOTIFY_SIGNAL)
+#define _TIF_NOTIFY_IPI (1<<TIF_NOTIFY_IPI)
#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)

--
2.34.1