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From: Usama Arif <usama.arif@bytedance.com>
To: dwmw2@infradead.org, tglx@linutronix.de, arjan@linux.intel.com
Cc: mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
	hpa@zytor.com, x86@kernel.org, pbonzini@redhat.com,
	paulmck@kernel.org, linux-kernel@vger.kernel.org,
	kvm@vger.kernel.org, rcu@vger.kernel.org, mimoja@mimoja.de,
	hewenliang4@huawei.com, thomas.lendacky@amd.com,
	seanjc@google.com, pmenzel@molgen.mpg.de,
	fam.zheng@bytedance.com, punit.agrawal@bytedance.com,
	simon.evans@bytedance.com, liangma@liangbit.com,
	David Woodhouse <dwmw@amazon.co.uk>
Subject: [PATCH v6 09/11] x86/mtrr: Avoid repeated save of MTRRs on boot-time CPU bringup
Date: Thu,  2 Feb 2023 21:56:23 +0000	[thread overview]
Message-ID: <20230202215625.3248306-10-usama.arif@bytedance.com> (raw)
In-Reply-To: <20230202215625.3248306-1-usama.arif@bytedance.com>

From: David Woodhouse <dwmw@amazon.co.uk>

There's no need to repeatedly save the BSP's MTRRs for each AP we bring
up at boot time. And there's no need to use smp_call_function_single()
even for the one time we *do* want to do it.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 arch/x86/kernel/cpu/mtrr/mtrr.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.c b/arch/x86/kernel/cpu/mtrr/mtrr.c
index 783f3210d582..b6eae3ad4414 100644
--- a/arch/x86/kernel/cpu/mtrr/mtrr.c
+++ b/arch/x86/kernel/cpu/mtrr/mtrr.c
@@ -721,11 +721,20 @@ void __init mtrr_bp_init(void)
  */
 void mtrr_save_state(void)
 {
+	static bool mtrr_saved;
 	int first_cpu;
 
 	if (!mtrr_enabled())
 		return;
 
+	if (system_state < SYSTEM_RUNNING) {
+		if (!mtrr_saved) {
+			mtrr_save_fixed_ranges(NULL);
+			mtrr_saved = true;
+		}
+		return;
+	}
+
 	first_cpu = cpumask_first(cpu_online_mask);
 	smp_call_function_single(first_cpu, mtrr_save_fixed_ranges, NULL, 1);
 }
-- 
2.25.1


  parent reply	other threads:[~2023-02-02 21:57 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-02 21:56 [PATCH v6 00/11] Parallel CPU bringup for x86_64 Usama Arif
2023-02-02 21:56 ` [PATCH v6 01/11] x86/apic/x2apic: Fix parallel handling of cluster_mask Usama Arif
2023-02-06 23:20   ` Thomas Gleixner
2023-02-07 10:57     ` David Woodhouse
2023-02-07 11:27       ` David Woodhouse
2023-02-07 14:24         ` Thomas Gleixner
2023-02-07 19:53           ` David Woodhouse
2023-02-07 20:58             ` Thomas Gleixner
2023-02-07 14:22       ` Thomas Gleixner
2023-02-02 21:56 ` [PATCH v6 02/11] cpu/hotplug: Move idle_thread_get() to <linux/smpboot.h> Usama Arif
2023-02-06 23:33   ` Thomas Gleixner
2023-02-07  1:24     ` Paul E. McKenney
2023-02-02 21:56 ` [PATCH v6 03/11] cpu/hotplug: Add dynamic parallel bringup states before CPUHP_BRINGUP_CPU Usama Arif
2023-02-06 23:43   ` Thomas Gleixner
2023-02-02 21:56 ` [PATCH v6 04/11] x86/smpboot: Reference count on smpboot_setup_warm_reset_vector() Usama Arif
2023-02-06 23:48   ` Thomas Gleixner
     [not found]     ` <57195f701f6d1d70ec440c9a28cbee4cfb81dc41.camel@amazon.co.uk>
2023-02-07 14:39       ` Thomas Gleixner
2023-02-07 16:50         ` Sean Christopherson
2023-02-07 19:48         ` [EXTERNAL][PATCH " David Woodhouse
2023-02-02 21:56 ` [PATCH v6 05/11] x86/smpboot: Split up native_cpu_up into separate phases and document them Usama Arif
2023-02-06 23:59   ` Thomas Gleixner
2023-02-02 21:56 ` [PATCH v6 06/11] x86/smpboot: Support parallel startup of secondary CPUs Usama Arif
2023-02-02 22:30   ` David Woodhouse
2023-02-02 22:50     ` [External] " Usama Arif
2023-02-03  8:14       ` David Woodhouse
2023-02-03 14:41         ` Arjan van de Ven
2023-02-03 18:17   ` Sean Christopherson
2023-02-07  0:07   ` Thomas Gleixner
2023-02-02 21:56 ` [PATCH v6 07/11] x86/smpboot: Disable parallel boot for AMD CPUs Usama Arif
2023-02-03 19:48   ` Kim Phillips
     [not found]     ` <d5ec64236ba75f0d3f3718fb69b2cb9169d8af0a.camel@amazon.co.uk>
2023-02-03 21:45       ` Kim Phillips
2023-02-03 22:25         ` [EXTERNAL][PATCH " David Woodhouse
2023-02-04  9:07     ` [PATCH " David Woodhouse
2023-02-04 10:09     ` David Woodhouse
2023-02-04 15:40     ` David Woodhouse
2023-02-04 18:18       ` Arjan van de Ven
2023-02-04 22:31         ` David Woodhouse
2023-02-05 22:13           ` [External] " Usama Arif
2023-02-06  8:05             ` David Woodhouse
2023-02-06 12:11               ` Usama Arif
2023-02-06 18:07                 ` Sean Christopherson
2023-02-06 17:58       ` Kim Phillips
2023-02-07 16:27         ` Kim Phillips
2023-02-07  0:23       ` Thomas Gleixner
2023-02-07 10:04         ` David Woodhouse
2023-02-07 14:44           ` Thomas Gleixner
2023-02-07  0:09   ` Thomas Gleixner
     [not found]     ` <cbd9e88e738dc0c479e87121ca82431731905c73.camel@amazon.co.uk>
2023-02-07 14:46       ` Thomas Gleixner
2023-02-02 21:56 ` [PATCH v6 08/11] x86/smpboot: Send INIT/SIPI/SIPI to secondary CPUs in parallel Usama Arif
2023-02-07  0:28   ` Thomas Gleixner
2023-02-02 21:56 ` Usama Arif [this message]
2023-02-02 21:56 ` [PATCH v6 10/11] x86/smpboot: Serialize topology updates for secondary bringup Usama Arif
2023-02-02 21:56 ` [PATCH v6 11/11] x86/smpboot: reuse timer calibration Usama Arif
2023-02-07  0:31   ` Thomas Gleixner
2023-02-07 23:16   ` Arjan van de Ven
2023-02-07 23:55     ` Thomas Gleixner
2023-02-05 19:17 ` [PATCH v6 00/11] Parallel CPU bringup for x86_64 Russ Anderson
2023-02-06  8:28   ` David Woodhouse
2023-02-06 12:18     ` [External] " Usama Arif

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