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

From: tip-bot for Peter Zijlstra
Date: Thu May 08 2014 - 06:47:07 EST


Commit-ID: 2a705ad65c9c393df1a684c780f890a29aab1128
Gitweb: http://git.kernel.org/tip/2a705ad65c9c393df1a684c780f890a29aab1128
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Fri, 11 Apr 2014 09:59:17 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 8 May 2014 09:16:53 +0200

sched/idle, alpha: 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>
Acked-by: Richard Henderson <rth@xxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Ivan Kokshaysky <ink@xxxxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Matt Turner <mattst88@xxxxxxxxx>
Cc: Richard Henderson <rth@xxxxxxxxxxx>
Cc: èæé <zhenglong.cai@xxxxxxxxxxx>
Cc: linux-alpha@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/n/tip-9tfzr196gs0n2afxv0ga8pc3@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/alpha/include/asm/thread_info.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/alpha/include/asm/thread_info.h b/arch/alpha/include/asm/thread_info.h
index 3d6ce6d..48bbea6 100644
--- a/arch/alpha/include/asm/thread_info.h
+++ b/arch/alpha/include/asm/thread_info.h
@@ -73,12 +73,14 @@ register struct thread_info *__current_thread_info __asm__("$8");
#define TIF_SYSCALL_AUDIT 4 /* syscall audit active */
#define TIF_DIE_IF_KERNEL 9 /* dik recursion lock */
#define TIF_MEMDIE 13 /* is terminating due to OOM killer */
+#define TIF_POLLING_NRFLAG 14 /* idle is polling for TIF_NEED_RESCHED */

#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
#define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT)
+#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)

/* Work to do on interrupt/exception return. */
#define _TIF_WORK_MASK (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
@@ -92,8 +94,6 @@ register struct thread_info *__current_thread_info __asm__("$8");
#define TS_UAC_NOFIX 0x0002 /* ! flags as they match */
#define TS_UAC_SIGBUS 0x0004 /* ! userspace part of 'osf_sysinfo' */
#define TS_RESTORE_SIGMASK 0x0008 /* restore signal mask in do_signal() */
-#define TS_POLLING 0x0010 /* idle task polling need_resched,
- skip sending interrupt */

#ifndef __ASSEMBLY__
#define HAVE_SET_RESTORE_SIGMASK 1
--
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