[PATCH v2 14/14] microblaze/thread_info: Introduce TIF_NOTIFY_IPI flag

K Prateek Nayak
2024-06-13T18:22:59Z

Add support for TIF_NOTIFY_IPI on MicroBlaze. 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: Michal Simek <monstr@monstr.eu>
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-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/microblaze/include/asm/thread_info.h | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/microblaze/include/asm/thread_info.h b/arch/microblaze/include/asm/thread_info.h
index a0ddd2a36fb9..953a334bb4fe 100644
--- a/arch/microblaze/include/asm/thread_info.h
+++ b/arch/microblaze/include/asm/thread_info.h
@@ -103,6 +103,7 @@ static inline struct thread_info *current_thread_info(void)
#define TIF_SINGLESTEP 4
#define TIF_NOTIFY_SIGNAL 5 /* signal notifications exist */
#define TIF_MEMDIE 6 /* is terminating due to OOM killer */
+#define TIF_NOTIFY_IPI 7 /* Pending IPI on TIF_POLLLING idle CPU */
#define TIF_SYSCALL_AUDIT 9 /* syscall auditing active */
#define TIF_SECCOMP 10 /* secure computing */

@@ -115,6 +116,7 @@ static inline struct thread_info *current_thread_info(void)
#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)
#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
#define _TIF_SECCOMP (1 << TIF_SECCOMP)
--
2.34.1