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Message-ID: <20240613181613.4329-7-kprateek.nayak@amd.com>
Date: Thu, 13 Jun 2024 18:16:05 +0000
From: K Prateek Nayak <kprateek.nayak@....com>
To: <linux-kernel@...r.kernel.org>
CC: "Gautham R. Shenoy" <gautham.shenoy@....com>, K Prateek Nayak
<kprateek.nayak@....com>, Richard Henderson <richard.henderson@...aro.org>,
Ivan Kokshaysky <ink@...assic.park.msu.ru>, Matt Turner <mattst88@...il.com>,
"Rafael J. Wysocki" <rafael@...nel.org>, Daniel Lezcano
<daniel.lezcano@...aro.org>, Ingo Molnar <mingo@...hat.com>, Peter Zijlstra
<peterz@...radead.org>, Juri Lelli <juri.lelli@...hat.com>, Vincent Guittot
<vincent.guittot@...aro.org>, Dietmar Eggemann <dietmar.eggemann@....com>,
Steven Rostedt <rostedt@...dmis.org>, Ben Segall <bsegall@...gle.com>, "Mel
Gorman" <mgorman@...e.de>, Daniel Bristot de Oliveira <bristot@...hat.com>,
Valentin Schneider <vschneid@...hat.com>, <linux-alpha@...r.kernel.org>,
<linux-pm@...r.kernel.org>
Subject: [PATCH v2 06/14] alpha/thread_info: Introduce TIF_NOTIFY_IPI flag
Add support for TIF_NOTIFY_IPI on Alpha. 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: Richard Henderson <richard.henderson@...aro.org>
Cc: Ivan Kokshaysky <ink@...assic.park.msu.ru>
Cc: Matt Turner <mattst88@...il.com>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>
Cc: Daniel Lezcano <daniel.lezcano@...aro.org>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Juri Lelli <juri.lelli@...hat.com>
Cc: Vincent Guittot <vincent.guittot@...aro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@....com>
Cc: Steven Rostedt <rostedt@...dmis.org>
Cc: Ben Segall <bsegall@...gle.com>
Cc: Mel Gorman <mgorman@...e.de>
Cc: Daniel Bristot de Oliveira <bristot@...hat.com>
Cc: Valentin Schneider <vschneid@...hat.com>
Cc: linux-alpha@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Cc: linux-pm@...r.kernel.org
Signed-off-by: K Prateek Nayak <kprateek.nayak@....com>
---
v1..v2:
o No changes.
---
arch/alpha/include/asm/thread_info.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/alpha/include/asm/thread_info.h b/arch/alpha/include/asm/thread_info.h
index 4a4d00b37986..8c17855c85c7 100644
--- a/arch/alpha/include/asm/thread_info.h
+++ b/arch/alpha/include/asm/thread_info.h
@@ -64,6 +64,7 @@ register unsigned long *current_stack_pointer __asm__ ("$30");
#define TIF_NEED_RESCHED 3 /* rescheduling necessary */
#define TIF_SYSCALL_AUDIT 4 /* syscall audit active */
#define TIF_NOTIFY_SIGNAL 5 /* signal notifications exist */
+#define TIF_NOTIFY_IPI 6 /* Pending IPI on TIF_POLLLING idle CPU */
#define TIF_DIE_IF_KERNEL 9 /* dik recursion lock */
#define TIF_MEMDIE 13 /* is terminating due to OOM killer */
#define TIF_POLLING_NRFLAG 14 /* idle is polling for TIF_NEED_RESCHED */
@@ -74,6 +75,7 @@ register unsigned long *current_stack_pointer __asm__ ("$30");
#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
#define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT)
#define _TIF_NOTIFY_SIGNAL (1<<TIF_NOTIFY_SIGNAL)
+#define _TIF_NOTIFY_IPI (1<<TIF_NOTIFY_IPI)
#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
/* Work to do on interrupt/exception return. */
--
2.34.1
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