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Message-Id: <cc7949234e3ac0ddb402764be5ed620035f964a6.1227725632.git.gorcunov@gmail.com>
Date: Wed, 26 Nov 2008 22:17:01 +0300
From: gorcunov@...il.com
To: mingo@...e.hu, tglx@...utronix.de, hpa@...or.com
Cc: linux-kernel@...r.kernel.org, heukelum@...tmail.fm,
Cyrill Gorcunov <gorcunov@...il.com>
Subject: [PATCH 2/5] x86: ret_from_fork - get rid of jump back
From: Cyrill Gorcunov <gorcunov@...il.com>
Impact: cleanup, microoptimization
Use straightforward jumping if possible, cpu like it.
Signed-off-by: Cyrill Gorcunov <gorcunov@...il.com>
---
arch/x86/kernel/entry_64.S | 10 ++++------
1 files changed, 4 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 098ba0b..7b52b0f 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -379,7 +379,10 @@ ENTRY(ret_from_fork)
GET_THREAD_INFO(%rcx)
testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT),TI_flags(%rcx)
CFI_REMEMBER_STATE
- jnz rff_trace
+ jz rff_action
+ movq %rsp,%rdi
+ call syscall_trace_leave
+ GET_THREAD_INFO(%rcx)
rff_action:
RESTORE_REST
testl $3,CS-ARGOFFSET(%rsp) # from kernel_thread?
@@ -389,11 +392,6 @@ rff_action:
RESTORE_TOP_OF_STACK %rdi, -ARGOFFSET
jmp ret_from_sys_call
CFI_RESTORE_STATE
-rff_trace:
- movq %rsp,%rdi
- call syscall_trace_leave
- GET_THREAD_INFO(%rcx)
- jmp rff_action
CFI_ENDPROC
END(ret_from_fork)
--
1.6.0.4.603.gbc9c0
--
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