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@infradead.org>
Acked-by: Richard Henderson <rth@twiddle.net>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: 蔡正龙 <zhenglong.cai@cs2c.com.cn>
Cc: linux-alpha@vger.kernel.org
Link: http://lkml.kernel.org/n/tip-9tfzr196gs0n2afxv0ga8pc3@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/alpha/include/asm/thread_info.h b/arch/alpha/include/asm/thread_info.h
index 3d6ce6d..48bbea6 100644 (file)
--- 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