Message-ID: <48FF20F6.1040505@fr.ibm.com>
Date: Wed, 22 Oct 2008 14:47:50 +0200
From: Cedric Le Goater <clg@fr.ibm.com>
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To: Andrey Mirkin <major@openvz.org>
CC: devel@openvz.org, Pavel Emelyanov <xemul@openvz.org>,
       containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [Devel] Re: [PATCH 08/10] Introduce functions to restart a process
References: <1224285098-573-1-git-send-email-major@openvz.org> <1224285098-573-9-git-send-email-major@openvz.org> <48FC4E0C.7050008@fr.ibm.com> <200810221249.55600.major@openvz.org>
In-Reply-To: <200810221249.55600.major@openvz.org>
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>>> +ENTRY(i386_ret_from_resume)
>>> +	CFI_STARTPROC
>>> +	pushl %eax
>>> +	CFI_ADJUST_CFA_OFFSET 4
>>> +	call schedule_tail
>>> +	GET_THREAD_INFO(%ebp)
>>> +	popl %eax
>>> +	CFI_ADJUST_CFA_OFFSET -4
>>> +	movl (%esp), %eax
>>> +	testl %eax, %eax
>>> +	jz    1f
>>> +	pushl %esp
>>> +	call  *%eax
>>> +	addl  $4, %esp
>>> +1:
>>> +	addl  $256, %esp
>>> +	jmp   ret_from_fork_tail
>>> +	CFI_ENDPROC
>>> +END(i386_ret_from_resume)
>> Could you explain why you need to do this
>>
>> 	call  *%eax
>>
>> is it related to the freezer code ?
> 
> It is not related to the freezer code actually.
> That is needed to restart syscalls. Right now I don't have a code in my 
> patchset which restarts a syscall, but later I plan to add it.
> In OpenVZ checkpointing we restart syscalls if process was caught in syscall 
> during checkpointing.

ok. I get it now. why 256 bytes of extra stack ? I'm sure it's not random. 

Thanks,

C.
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