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[RFC,31/86] x86/thread_info: add TIF_NEED_RESCHED_LAZY

Message ID 20231107215742.363031-32-ankur.a.arora@oracle.com (mailing list archive)
State New
Headers show
Series Make the kernel preemptible | expand

Commit Message

Ankur Arora Nov. 7, 2023, 9:57 p.m. UTC 
Add a new flag, TIF_NEED_RESCHED_LAZY which with TIF_NEED_RESCHED
gives the scheduler two levels of rescheduling priority:
TIF_NEED_RESCHED means that rescheduling happens at the next
opportunity; TIF_NEED_RESCHED_LAZY is used to note that a
reschedule is needed but does not impose any other constraints
on the scheduler.

Originally-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
---
 arch/x86/include/asm/thread_info.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Comments

Steven Rostedt Nov. 7, 2023, 11:26 p.m. UTC | #1 
On Tue,  7 Nov 2023 13:57:17 -0800
Ankur Arora <ankur.a.arora@oracle.com> wrote:

> Add a new flag, TIF_NEED_RESCHED_LAZY which with TIF_NEED_RESCHED
> gives the scheduler two levels of rescheduling priority:
> TIF_NEED_RESCHED means that rescheduling happens at the next
> opportunity; TIF_NEED_RESCHED_LAZY is used to note that a
> reschedule is needed but does not impose any other constraints
> on the scheduler.

Please add:

Link: https://lore.kernel.org/lkml/87cyyfxd4k.ffs@tglx/
Link: https://lore.kernel.org/lkml/87jzshhexi.ffs@tglx/

For each of the patches that were based off of Thomas's patch.

Thanks!

-- Steve



> 
> Originally-by: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
> ---
>  arch/x86/include/asm/thread_info.h | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
> index d63b02940747..114d12120051 100644
> --- a/arch/x86/include/asm/thread_info.h
> +++ b/arch/x86/include/asm/thread_info.h
> @@ -81,8 +81,9 @@ 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	/* Lazy rescheduling */
> +#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 */
> @@ -104,6 +105,7 @@ 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)
diff mbox series

Patch

diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index d63b02940747..114d12120051 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -81,8 +81,9 @@  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	/* Lazy rescheduling */
+#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 */
@@ -104,6 +105,7 @@  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)