[tip:sched/core] sched/idle, ia64: Switch from TS_POLLING to TIF_POLLING_NRFLAG

From: tip-bot for Peter Zijlstra
Date: Thu May 08 2014 - 06:47:22 EST


Commit-ID: 04075425331f91f7176a34232c21b63af0eafc53
Gitweb: http://git.kernel.org/tip/04075425331f91f7176a34232c21b63af0eafc53
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Fri, 11 Apr 2014 09:59:08 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
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@xxxxxxxxxxxxx>
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: linux-ia64@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/n/tip-6633akuird5hi3si4gbegkm8@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
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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