linux-kernel - [tip: sched/core] sched, x86: Enable Lazy preemption

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Message-ID: <173089012568.32228.5430722974826547973.tip-bot2@tip-bot2>
Date: Wed, 06 Nov 2024 10:48:45 -0000
From: "tip-bot2 for Peter Zijlstra" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: "Peter Zijlstra (Intel)" <peterz@...radead.org>,
 Sebastian Andrzej Siewior <bigeasy@...utronix.de>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: sched/core] sched, x86: Enable Lazy preemption

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     476e8583ca16eecec0a3a28b6ee7130f4e369389
Gitweb:        https://git.kernel.org/tip/476e8583ca16eecec0a3a28b6ee7130f4e369389
Author:        Peter Zijlstra <peterz@...radead.org>
AuthorDate:    Fri, 04 Oct 2024 14:46:54 +02:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Tue, 05 Nov 2024 12:55:38 +01:00

sched, x86: Enable Lazy preemption

Add the TIF bit and select the Kconfig symbol to make it go.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Link: https://lkml.kernel.org/r/20241007075055.555778919@infradead.org
---
 arch/x86/Kconfig                   | 1 +
 arch/x86/include/asm/thread_info.h | 6 ++++--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 2852fcd..b76aa7f 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -93,6 +93,7 @@ config X86
 	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
 	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
 	select ARCH_HAS_PMEM_API		if X86_64
+	select ARCH_HAS_PREEMPT_LAZY
 	select ARCH_HAS_PTE_DEVMAP		if X86_64
 	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_HW_PTE_YOUNG
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 12da7df..75bb390 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -87,8 +87,9 @@ struct thread_info {
 #define TIF_NOTIFY_RESUME	1	/* callback before returning to user */
 #define TIF_SIGPENDING		2	/* signal pending */
 #define TIF_NEED_RESCHED	3	/* rescheduling necessary */
-#define TIF_SINGLESTEP		4	/* reenable singlestep on user return*/
-#define TIF_SSBD		5	/* Speculative store bypass disable */
+#define TIF_NEED_RESCHED_LAZY	4	/* rescheduling necessary */
+#define TIF_SINGLESTEP		5	/* reenable singlestep on user return*/
+#define TIF_SSBD		6	/* Speculative store bypass disable */
 #define TIF_SPEC_IB		9	/* Indirect branch speculation mitigation */
 #define TIF_SPEC_L1D_FLUSH	10	/* Flush L1D on mm switches (processes) */
 #define TIF_USER_RETURN_NOTIFY	11	/* notify kernel of userspace return */
@@ -110,6 +111,7 @@ struct thread_info {
 #define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
 #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
 #define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
+#define _TIF_NEED_RESCHED_LAZY	(1 << TIF_NEED_RESCHED_LAZY)
 #define _TIF_SINGLESTEP		(1 << TIF_SINGLESTEP)
 #define _TIF_SSBD		(1 << TIF_SSBD)
 #define _TIF_SPEC_IB		(1 << TIF_SPEC_IB)