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From: K Prateek Nayak <kprateek.nayak@amd.com>
To: <linux-kernel@vger.kernel.org>
CC: "Gautham R. Shenoy" <gautham.shenoy@amd.com>, K Prateek Nayak
	<kprateek.nayak@amd.com>, Jonas Bonn <jonas@southpole.se>, "Stefan
 Kristiansson" <stefan.kristiansson@saunalahti.fi>, Stafford Horne
	<shorne@gmail.com>, "Rafael J. Wysocki" <rafael@kernel.org>, Daniel Lezcano
	<daniel.lezcano@linaro.org>, Ingo Molnar <mingo@redhat.com>, Peter Zijlstra
	<peterz@infradead.org>, Juri Lelli <juri.lelli@redhat.com>, Vincent Guittot
	<vincent.guittot@linaro.org>, Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Steven Rostedt <rostedt@goodmis.org>, Ben Segall <bsegall@google.com>, "Mel
 Gorman" <mgorman@suse.de>, Daniel Bristot de Oliveira <bristot@redhat.com>,
	Valentin Schneider <vschneid@redhat.com>, <linux-openrisc@vger.kernel.org>,
	<linux-pm@vger.kernel.org>
Subject: [RFC PATCH 07/14] openrisc/thread_info: Introduce TIF_NOTIFY_IPI flag
Date: Tue, 20 Feb 2024 22:44:50 +0530
Message-ID: <20240220171457.703-8-kprateek.nayak@amd.com>
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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>
---
 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