Commit 7c805795 authored Oct 23, 2019 by Thomas Gleixner Committed by Frederic Weisbecker Feb 14, 2020

x86/entry: Remove _TIF_NOHZ from _TIF_WORK_SYSCALL_ENTRY



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>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>

parent bb6d3fb3

arch/x86/include/asm/thread_info.h

+2 −6

Original line number	Diff line number	Diff line
		@@ -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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