diff mbox series

[v6,09/11] x86/mtrr: Avoid repeated save of MTRRs on boot-time CPU bringup

Message ID 20230202215625.3248306-10-usama.arif@bytedance.com (mailing list archive)
State New, archived
Headers show
Series Parallel CPU bringup for x86_64 | expand

Commit Message

Usama Arif Feb. 2, 2023, 9:56 p.m. UTC 
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 mbox series

Patch

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);
 }