Messages in this thread Patch in this message | | | Date | Thu, 19 Sep 2019 17:03:16 +0200 | From | Thomas Gleixner <> | Subject | [RFC patch 02/15] x86/entry: Remove _TIF_NOHZ from _TIF_WORK_SYSCALL_ENTRY |
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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@linutronix.de> --- 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 \
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