linux-kernel - Re: [PATCH 2/5] x86: ret_from_fork

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Message-ID: <20081126201054.GB2624@localhost>
Date:	Wed, 26 Nov 2008 23:10:54 +0300
From:	Cyrill Gorcunov <gorcunov@...il.com>
To:	Andi Kleen <andi@...stfloor.org>
Cc:	mingo@...e.hu, tglx@...utronix.de, hpa@...or.com,
	linux-kernel@...r.kernel.org, heukelum@...tmail.fm
Subject: Re: [PATCH 2/5] x86: ret_from_fork - get rid of jump back

[Andi Kleen - Wed, Nov 26, 2008 at 09:04:33PM +0100]
| gorcunov@...il.com writes:
| > --- 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)
| 
| The uncommon path is supposed to be out of line. I don't think
| the CPU will like that.
| 
| -Andi
| 
| >  rff_action:
| 
| -- 
| ak@...ux.intel.com
| 

Aha! Thanks Andi for review.

		- Cyrill -
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