From: Usama Arif <usama.arif@bytedance.com>
To: dwmw2@infradead.org, tglx@linutronix.de
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 8/9] x86/mtrr: Avoid repeated save of MTRRs on boot-time CPU bringup
Date: Wed, 1 Feb 2023 20:43:37 +0000 [thread overview]
Message-ID: <20230201204338.1337562-9-usama.arif@bytedance.com> (raw)
In-Reply-To: <20230201204338.1337562-1-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>
---
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 2746cac9d8a9..2884017586f1 100644
--- a/arch/x86/kernel/cpu/mtrr/mtrr.c
+++ b/arch/x86/kernel/cpu/mtrr/mtrr.c
@@ -814,11 +814,20 @@ void mtrr_ap_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
next prev parent reply other threads:[~2023-02-01 20:46 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-01 20:43 [PATCH 0/9] Parallel CPU bringup for x86_64 Usama Arif
2023-02-01 20:43 ` [PATCH 1/9] x86/apic/x2apic: Fix parallel handling of cluster_mask Usama Arif
2023-02-01 20:43 ` [PATCH 2/9] cpu/hotplug: Move idle_thread_get() to <linux/smpboot.h> Usama Arif
2023-02-01 20:43 ` [PATCH 3/9] cpu/hotplug: Add dynamic parallel bringup states before CPUHP_BRINGUP_CPU Usama Arif
2023-02-01 20:43 ` [PATCH 4/9] x86/smpboot: Reference count on smpboot_setup_warm_reset_vector() Usama Arif
2023-02-01 20:43 ` [PATCH 5/9] x86/smpboot: Split up native_cpu_up into separate phases and document them Usama Arif
2023-02-01 20:43 ` [PATCH 6/9] x86/smpboot: Support parallel startup of secondary CPUs Usama Arif
2023-02-01 20:43 ` [PATCH 7/9] x86/smpboot: Send INIT/SIPI/SIPI to secondary CPUs in parallel Usama Arif
2023-02-01 20:43 ` Usama Arif [this message]
2023-02-01 20:43 ` [PATCH 9/9] x86/smpboot: Serialize topology updates for secondary bringup Usama Arif
2023-02-02 10:02 ` [PATCH 0/9] Parallel CPU bringup for x86_64 David Woodhouse
2023-02-02 21:59 ` Usama Arif
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