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Message-ID: <168422819946.404.17515488991384731626.tip-bot2@tip-bot2>
Date: Tue, 16 May 2023 09:09:59 -0000
From: "tip-bot2 for Thomas Gleixner" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Thomas Gleixner <tglx@...utronix.de>,
"Peter Zijlstra (Intel)" <peterz@...radead.org>,
Michael Kelley <mikelley@...rosoft.com>,
Oleksandr Natalenko <oleksandr@...alenko.name>,
Helge Deller <deller@....de>,
"Guilherme G. Piccoli" <gpiccoli@...lia.com>, x86@...nel.org,
linux-kernel@...r.kernel.org
Subject: [tip: smp/core] x86/smpboot: Remove wait for cpu_online()
The following commit has been merged into the smp/core branch of tip:
Commit-ID: e464640cf7af12f3c2748065936b95eae1f735ba
Gitweb: https://git.kernel.org/tip/e464640cf7af12f3c2748065936b95eae1f735ba
Author: Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Fri, 12 May 2023 23:07:22 +02:00
Committer: Peter Zijlstra <peterz@...radead.org>
CommitterDate: Mon, 15 May 2023 13:44:54 +02:00
x86/smpboot: Remove wait for cpu_online()
Now that the core code drops sparse_irq_lock after the idle thread
synchronized, it's pointless to wait for the AP to mark itself online.
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Tested-by: Michael Kelley <mikelley@...rosoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@...alenko.name>
Tested-by: Helge Deller <deller@....de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@...lia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205256.316417181@linutronix.de
---
arch/x86/kernel/smpboot.c | 26 ++------------------------
1 file changed, 2 insertions(+), 24 deletions(-)
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 3f731be..4349e8a 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -275,7 +275,6 @@ static void notrace start_secondary(void *unused)
* half valid vector space.
*/
lock_vector_lock();
- /* Sync point with do_wait_cpu_online() */
set_cpu_online(smp_processor_id(), true);
lapic_online();
unlock_vector_lock();
@@ -1104,20 +1103,6 @@ static int wait_cpu_initialized(unsigned int cpu)
return 0;
}
-/*
- * Bringup step three: Wait for the target AP to reach set_cpu_online() in
- * start_secondary().
- */
-static void wait_cpu_online(unsigned int cpu)
-{
- /*
- * Wait for the AP to mark itself online, so the core caller
- * can drop sparse_irq_lock.
- */
- while (!cpu_online(cpu))
- schedule();
-}
-
static int native_kick_ap(unsigned int cpu, struct task_struct *tidle)
{
int apicid = apic->cpu_present_to_apicid(cpu);
@@ -1164,16 +1149,9 @@ int native_cpu_up(unsigned int cpu, struct task_struct *tidle)
int ret;
ret = native_kick_ap(cpu, tidle);
- if (ret)
- goto out;
-
- ret = wait_cpu_initialized(cpu);
- if (ret)
- goto out;
-
- wait_cpu_online(cpu);
+ if (!ret)
+ ret = wait_cpu_initialized(cpu);
-out:
/* Cleanup possible dangling ends... */
if (x86_platform.legacy.warm_reset)
smpboot_restore_warm_reset_vector();
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