linux-kernel - [tip:sched/core] sched/idle, ia64: Switch from TS_POLLING to TIF_POLLING

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Message-ID: <tip-6633akuird5hi3si4gbegkm8@git.kernel.org>
Date:	Thu, 8 May 2014 03:46:38 -0700
From:	tip-bot for Peter Zijlstra <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...nel.org,
	torvalds@...ux-foundation.org, peterz@...radead.org,
	tony.luck@...el.com, luto@...capital.net, fenghua.yu@...el.com,
	tglx@...utronix.de
Subject: [tip:sched/core] sched/idle, ia64:
  Switch from TS_POLLING to TIF_POLLING_NRFLAG

Commit-ID:  04075425331f91f7176a34232c21b63af0eafc53
Gitweb:     http://git.kernel.org/tip/04075425331f91f7176a34232c21b63af0eafc53
Author:     Peter Zijlstra <peterz@...radead.org>
AuthorDate: Fri, 11 Apr 2014 09:59:08 +0200
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Thu, 8 May 2014 09:16:55 +0200

sched/idle, ia64: Switch from TS_POLLING to TIF_POLLING_NRFLAG

Standardize the idle polling indicator to TIF_POLLING_NRFLAG such that
both TIF_NEED_RESCHED and TIF_POLLING_NRFLAG are in the same word.
This will allow us, using fetch_or(), to both set NEED_RESCHED and
check for POLLING_NRFLAG in a single operation and avoid pointless
wakeups.

Changing from the non-atomic thread_info::status flags to the atomic
thread_info::flags shouldn't be a big issue since most polling state
changes were followed/preceded by a full memory barrier anyway.

Signed-off-by: Peter Zijlstra <peterz@...radead.org>
Cc: Fenghua Yu <fenghua.yu@...el.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Tony Luck <tony.luck@...el.com>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: linux-ia64@...r.kernel.org
Link: http://lkml.kernel.org/n/tip-6633akuird5hi3si4gbegkm8@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/ia64/include/asm/thread_info.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/ia64/include/asm/thread_info.h b/arch/ia64/include/asm/thread_info.h
index 5957cf6..5b17418 100644
--- a/arch/ia64/include/asm/thread_info.h
+++ b/arch/ia64/include/asm/thread_info.h
@@ -107,6 +107,7 @@ struct thread_info {
 #define TIF_MCA_INIT		18	/* this task is processing MCA or INIT */
 #define TIF_DB_DISABLED		19	/* debug trap disabled for fsyscall */
 #define TIF_RESTORE_RSE		21	/* user RBS is newer than kernel RBS */
+#define TIF_POLLING_NRFLAG	22	/* idle is polling for TIF_NEED_RESCHED */
 
 #define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
 #define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
@@ -118,6 +119,7 @@ struct thread_info {
 #define _TIF_MCA_INIT		(1 << TIF_MCA_INIT)
 #define _TIF_DB_DISABLED	(1 << TIF_DB_DISABLED)
 #define _TIF_RESTORE_RSE	(1 << TIF_RESTORE_RSE)
+#define _TIF_POLLING_NRFLAG	(1 << TIF_POLLING_NRFLAG)
 
 /* "work to do on user-return" bits */
 #define TIF_ALLWORK_MASK	(_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SYSCALL_AUDIT|\
@@ -125,7 +127,6 @@ struct thread_info {
 /* like TIF_ALLWORK_BITS but sans TIF_SYSCALL_TRACE or TIF_SYSCALL_AUDIT */
 #define TIF_WORK_MASK		(TIF_ALLWORK_MASK&~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT))
 
-#define TS_POLLING		1 	/* true if in idle loop and not sleeping */
 #define TS_RESTORE_SIGMASK	2	/* restore signal mask in do_signal() */
 
 #ifndef __ASSEMBLY__
--
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