[PATCH] i386/x86-64/ia64: Move polling flag into thread_info_status

During some profiling I noticed that default_idle causes a lot of
memory traffic. I think that is caused by the atomic operations
to clear/set the polling flag in thread_info. There is actually
no reason to make this atomic - only the idle thread does it
to itself, other CPUs only read it. So I moved it into ti->status.

Converted i386/x86-64/ia64 for now because that was the easiest
way to fix ACPI which also manipulates these flags in its idle
function.

Cc: Nick Piggin <npiggin@novell.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 13 insertions, 5 deletions

diff --git a/include/asm-i386/thread_info.h b/include/asm-i386/thread_info.h
index 8420ed1..fdbc7f4 100644
--- a/include/asm-i386/thread_info.h
+++ b/include/asm-i386/thread_info.h
@@ -140,8 +140,7 @@ register unsigned long current_stack_pointer asm("esp") __attribute_used__;
 #define TIF_SYSCALL_AUDIT	7	/* syscall auditing active */
 #define TIF_SECCOMP		8	/* secure computing */
 #define TIF_RESTORE_SIGMASK	9	/* restore signal mask in do_signal() */
-#define TIF_POLLING_NRFLAG	16	/* true if poll_idle() is polling TIF_NEED_RESCHED */
-#define TIF_MEMDIE		17
+#define TIF_MEMDIE		16
 
 #define _TIF_SYSCALL_TRACE	(1<<TIF_SYSCALL_TRACE)
 #define _TIF_NOTIFY_RESUME	(1<<TIF_NOTIFY_RESUME)
@@ -153,7 +152,6 @@ register unsigned long current_stack_pointer asm("esp") __attribute_used__;
 #define _TIF_SYSCALL_AUDIT	(1<<TIF_SYSCALL_AUDIT)
 #define _TIF_SECCOMP		(1<<TIF_SECCOMP)
 #define _TIF_RESTORE_SIGMASK	(1<<TIF_RESTORE_SIGMASK)
-#define _TIF_POLLING_NRFLAG	(1<<TIF_POLLING_NRFLAG)
 
 /* work to do on interrupt/exception return */
 #define _TIF_WORK_MASK \
@@ -170,6 +168,9 @@ register unsigned long current_stack_pointer asm("esp") __attribute_used__;
  * have to worry about atomic accesses.
  */
 #define TS_USEDFPU		0x0001	/* FPU was used by this task this quantum (SMP) */
+#define TS_POLLING		0x0002	/* True if in idle loop and not sleeping */
+
+#define tsk_is_polling(t) ((t)->thread_info->status & TS_POLLING)
 
 #endif /* __KERNEL__ */
 
diff --git a/include/asm-ia64/thread_info.h b/include/asm-ia64/thread_info.h
index e5392c4..8bc9869 100644
--- a/include/asm-ia64/thread_info.h
+++ b/include/asm-ia64/thread_info.h
@@ -27,6 +27,7 @@ struct thread_info {
 	__u32 flags;			/* thread_info flags (see TIF_*) */
 	__u32 cpu;			/* current CPU */
 	__u32 last_cpu;			/* Last CPU thread ran on */
+	__u32 status;			/* Thread synchronous flags */
 	mm_segment_t addr_limit;	/* user-level address space limit */
 	int preempt_count;		/* 0=premptable, <0=BUG; will also serve as bh-counter */
 	struct restart_block restart_block;
@@ -103,4 +104,8 @@ 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 tsk_is_polling(t) ((t)->thread_info->status & TS_POLLING)
+
 #endif /* _ASM_IA64_THREAD_INFO_H */
diff --git a/include/asm-x86_64/thread_info.h b/include/asm-x86_64/thread_info.h
index 4ac0e0a..b5e8821 100644
--- a/include/asm-x86_64/thread_info.h
+++ b/include/asm-x86_64/thread_info.h
@@ -101,7 +101,7 @@ static inline struct thread_info *stack_thread_info(void)
 #define TIF_IRET		5	/* force IRET */
 #define TIF_SYSCALL_AUDIT	7	/* syscall auditing active */
 #define TIF_SECCOMP		8	/* secure computing */
-#define TIF_POLLING_NRFLAG	16	/* true if poll_idle() is polling TIF_NEED_RESCHED */
+/* 16 free */
 #define TIF_IA32		17	/* 32bit process */ 
 #define TIF_FORK		18	/* ret_from_fork */
 #define TIF_ABI_PENDING		19
@@ -115,7 +115,6 @@ static inline struct thread_info *stack_thread_info(void)
 #define _TIF_IRET		(1<<TIF_IRET)
 #define _TIF_SYSCALL_AUDIT	(1<<TIF_SYSCALL_AUDIT)
 #define _TIF_SECCOMP		(1<<TIF_SECCOMP)
-#define _TIF_POLLING_NRFLAG	(1<<TIF_POLLING_NRFLAG)
 #define _TIF_IA32		(1<<TIF_IA32)
 #define _TIF_FORK		(1<<TIF_FORK)
 #define _TIF_ABI_PENDING	(1<<TIF_ABI_PENDING)
@@ -137,6 +136,9 @@ static inline struct thread_info *stack_thread_info(void)
  */
 #define TS_USEDFPU		0x0001	/* FPU was used by this task this quantum (SMP) */
 #define TS_COMPAT		0x0002	/* 32bit syscall active */
+#define TS_POLLING		0x0004	/* true if in idle loop and not sleeping */
+
+#define tsk_is_polling(t) ((t)->thread_info->status & TS_POLLING)
 
 #endif /* __KERNEL__ */