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@infradead.org>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-35zzwlvwr7cp8xj196y10yyx@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/tile/include/asm/thread_info.h b/arch/tile/include/asm/thread_info.h
index 729aa107f64e6391cb435ff1f5c038065eafe3b2..d767ff9f59b9c1532aa14dd8c8b342cd9a82155d 100644 (file)
--- 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__