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Message-Id: <20240528003521.979836-9-ankur.a.arora@oracle.com>
Date: Mon, 27 May 2024 17:34:54 -0700
From: Ankur Arora <ankur.a.arora@...cle.com>
To: linux-kernel@...r.kernel.org
Cc: tglx@...utronix.de, peterz@...radead.org, torvalds@...ux-foundation.org,
paulmck@...nel.org, rostedt@...dmis.org, mark.rutland@....com,
juri.lelli@...hat.com, joel@...lfernandes.org, raghavendra.kt@....com,
sshegde@...ux.ibm.com, boris.ostrovsky@...cle.com,
konrad.wilk@...cle.com, Ankur Arora <ankur.a.arora@...cle.com>,
Andy Lutomirski <luto@...nel.org>
Subject: [PATCH v2 08/35] entry: handle lazy rescheduling at user-exit
The scheduling policy for TIF_NEED_RESCHED_LAZY is to allow the
running task to voluntarily schedule out, running it to completion.
For archs with GENERIC_ENTRY, do this by adding a check in
exit_to_user_mode_loop().
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Andy Lutomirski <luto@...nel.org>
Originally-by: Thomas Gleixner <tglx@...utronix.de>
Link: https://lore.kernel.org/lkml/87jzshhexi.ffs@tglx/
Signed-off-by: Ankur Arora <ankur.a.arora@...cle.com>
---
include/linux/entry-common.h | 2 +-
kernel/entry/common.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index b0fb775a600d..f5bb19369973 100644
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -65,7 +65,7 @@
#define EXIT_TO_USER_MODE_WORK \
(_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_UPROBE | \
_TIF_NEED_RESCHED | _TIF_PATCH_PENDING | _TIF_NOTIFY_SIGNAL | \
- ARCH_EXIT_TO_USER_MODE_WORK)
+ _TIF_NEED_RESCHED_LAZY | ARCH_EXIT_TO_USER_MODE_WORK)
/**
* arch_enter_from_user_mode - Architecture specific sanity check for user mode regs
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index 90843cc38588..bcb23c866425 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -98,7 +98,7 @@ __always_inline unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
local_irq_enable_exit_to_user(ti_work);
- if (ti_work & _TIF_NEED_RESCHED)
+ if (ti_work & (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY))
schedule();
if (ti_work & _TIF_UPROBE)
--
2.31.1
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