From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Evaluating _TIF_NOHZ to decide whether to use the slow syscall entry path
is not only pointless, it's actually counterproductive:
1) Context tracking code is invoked unconditionally before that flag is
evaluated.
2) If the flag is set the slow path is invoked for nothing due to #1
Remove it.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/include/asm/thread_info.h | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -133,14 +133,10 @@ struct thread_info {
#define _TIF_X32 (1 << TIF_X32)
#define _TIF_FSCHECK (1 << TIF_FSCHECK)
-/*
- * work to do in syscall_trace_enter(). Also includes TIF_NOHZ for
- * enter_from_user_mode()
- */
+/* Work to do before invoking the actual syscall. */
#define _TIF_WORK_SYSCALL_ENTRY \
(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | _TIF_SYSCALL_AUDIT | \
- _TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT | \
- _TIF_NOHZ)
+ _TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT)
/* flags to check in __switch_to() */
#define _TIF_WORK_CTXSW_BASE \
