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

From: tip-bot for Peter Zijlstra
Date: Thu May 08 2014 - 06:49:36 EST


Commit-ID: b3a8cb18ce284b5c47517b681c42fcb9d8a99992
Gitweb: http://git.kernel.org/tip/b3a8cb18ce284b5c47517b681c42fcb9d8a99992
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Fri, 11 Apr 2014 09:59:13 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 8 May 2014 09:16:54 +0200

sched/idle, tile: 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: Chris Metcalf <cmetcalf@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Chris Metcalf <cmetcalf@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-35zzwlvwr7cp8xj196y10yyx@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/tile/include/asm/thread_info.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/tile/include/asm/thread_info.h b/arch/tile/include/asm/thread_info.h
index 729aa10..d767ff9 100644
--- a/arch/tile/include/asm/thread_info.h
+++ b/arch/tile/include/asm/thread_info.h
@@ -129,6 +129,7 @@ extern void _cpu_idle(void);
#define TIF_MEMDIE 7 /* OOM killer at work */
#define TIF_NOTIFY_RESUME 8 /* callback before returning to user */
#define TIF_SYSCALL_TRACEPOINT 9 /* syscall tracepoint instrumentation */
+#define TIF_POLLING_NRFLAG 10 /* idle is polling for TIF_NEED_RESCHED */

#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
@@ -140,6 +141,7 @@ extern void _cpu_idle(void);
#define _TIF_MEMDIE (1<<TIF_MEMDIE)
#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
#define _TIF_SYSCALL_TRACEPOINT (1<<TIF_SYSCALL_TRACEPOINT)
+#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)

/* Work to do on any return to user space. */
#define _TIF_ALLWORK_MASK \
@@ -162,7 +164,6 @@ extern void _cpu_idle(void);
#ifdef __tilegx__
#define TS_COMPAT 0x0001 /* 32-bit compatibility mode */
#endif
-#define TS_POLLING 0x0004 /* in idle loop but not sleeping */
#define TS_RESTORE_SIGMASK 0x0008 /* restore signal mask in do_signal */

#ifndef __ASSEMBLY__
--
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