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authorAndy Lutomirski <luto@kernel.org>2015-10-06 02:48:19 +0200
committerIngo Molnar <mingo@kernel.org>2015-10-09 09:41:12 +0200
commit33c52129f45e06d9ce23e1a3d50bf9fd6770748b (patch)
tree7252b2e12e4441966f13a7519649308aef421bcb /arch/x86/entry/common.c
parentx86/entry: Make irqs_disabled checks in exit code depend on lockdep (diff)
downloadlinux-33c52129f45e06d9ce23e1a3d50bf9fd6770748b.tar.xz
linux-33c52129f45e06d9ce23e1a3d50bf9fd6770748b.zip
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>
Diffstat (limited to 'arch/x86/entry/common.c')
-rw-r--r--arch/x86/entry/common.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 03aacd188458..d5eee851071c 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -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