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x86/entry: Force inlining of 32-bit syscall code 

On systems that support fast syscalls, we only really care about
the performance of the fast syscall path.  Forcibly inline it
and add a likely annotation.

This saves 4-6 cycles.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/8472036ff1f4b426b4c4c3e3d0b3bf5264407c0c.1444091585.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andy Lutomirski 2015-10-05 17:48:19 -07:00 committed by Ingo Molnar
parent 460d12453e
commit 33c52129f4
1 changed files with 5 additions and 3 deletions
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8
arch/x86/entry/common.c
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@ -324,9 +324,11 @@ __visible void syscall_return_slowpath(struct pt_regs *regs)
#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
/*
* Does a 32-bit syscall. Called with IRQs on and does all entry and
* exit work and returns with IRQs off.
* exit work and returns with IRQs off. This function is extremely hot
* in workloads that use it, and it's usually called from
* do_fast_syscall_32, so forcibly inline it to improve performance.
*/
static void do_syscall_32_irqs_on(struct pt_regs *regs)
static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs)
{
struct thread_info *ti = pt_regs_to_thread_info(regs);
unsigned int nr = (unsigned int)regs->orig_ax;
@ -345,7 +347,7 @@ static void do_syscall_32_irqs_on(struct pt_regs *regs)
nr = syscall_trace_enter(regs);
}
if (nr < IA32_NR_syscalls) {
if (likely(nr < IA32_NR_syscalls)) {
/*
* It's possible that a 32-bit syscall implementation
* takes a 64-bit parameter but nonetheless assumes that