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@infradead.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: linux-ia64@vger.kernel.org
Link: http://lkml.kernel.org/n/tip-6633akuird5hi3si4gbegkm8@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/ia64/include/asm/thread_info.h b/arch/ia64/include/asm/thread_info.h
index 5957cf6..5b17418 100644 (file)
--- 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__