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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Prarit Bhargava <prarit@redhat.com>,
	Richard Henderson <rth@twiddle.net>,
	Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
	Matt Turner <mattst88@gmail.com>, Sasha Levin <sashal@kernel.org>,
	linux-alpha@vger.kernel.org
Subject: [PATCH AUTOSEL 4.4 3/4] alpha: Send stop IPI to send to online CPUs
Date: Tue,  3 Aug 2021 07:44:50 -0400	[thread overview]
Message-ID: <20210803114451.2253268-3-sashal@kernel.org> (raw)
In-Reply-To: <20210803114451.2253268-1-sashal@kernel.org>

From: Prarit Bhargava <prarit@redhat.com>

[ Upstream commit caace6ca4e06f09413fb8f8a63319594cfb7d47d ]

This issue was noticed while debugging a shutdown issue where some
secondary CPUs are not being shutdown correctly.  A fix for that [1] requires
that secondary cpus be offlined using the cpu_online_mask so that the
stop operation is a no-op if CPU HOTPLUG is disabled.  I, like the author in
[1] looked at the architectures and found that alpha is one of two
architectures that executes smp_send_stop() on all possible CPUs.

On alpha, smp_send_stop() sends an IPI to all possible CPUs but only needs
to send them to online CPUs.

Send the stop IPI to only the online CPUs.

[1] https://lkml.org/lkml/2020/1/10/250

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/alpha/kernel/smp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index 2f24447fef92..1543b571bd99 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -584,7 +584,7 @@ void
 smp_send_stop(void)
 {
 	cpumask_t to_whom;
-	cpumask_copy(&to_whom, cpu_possible_mask);
+	cpumask_copy(&to_whom, cpu_online_mask);
 	cpumask_clear_cpu(smp_processor_id(), &to_whom);
 #ifdef DEBUG_IPI_MSG
 	if (hard_smp_processor_id() != boot_cpu_id)
-- 
2.30.2


  parent reply	other threads:[~2021-08-03 11:46 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-03 11:44 [PATCH AUTOSEL 4.4 1/4] reiserfs: add check for root_inode in reiserfs_fill_super Sasha Levin
2021-08-03 11:44 ` [PATCH AUTOSEL 4.4 2/4] reiserfs: check directory items on read from disk Sasha Levin
2021-08-03 11:44 ` Sasha Levin [this message]
2021-08-03 11:44 ` [PATCH AUTOSEL 4.4 4/4] net/qla3xxx: fix schedule while atomic in ql_wait_for_drvr_lock and ql_adapter_reset Sasha Levin

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