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Date: Fri, 31 Oct 2003 07:24:45 +0800
From: David Xu <davidxu@freebsd.org>
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Subject: Re: cvs commit: src/sys/i386/i386 trap.c src/sys/kern kern_sig.c
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John Baldwin wrote:

>On 30-Oct-2003 David Xu wrote:
>  
>
>>davidxu     2003/10/29 18:55:43 PST
>>
>>  FreeBSD src repository
>>
>>  Modified files:
>>    sys/i386/i386        trap.c 
>>    sys/kern             kern_sig.c 
>>  Log:
>>  Try to fetch thread mailbox address in page fault trap, so when thread
>>  blocks in page fault hanlder, and upcall thread can be scheduled. It is
>>  useful if process is doing lots of mmap based I/O.
>>    
>>
>
>Does this need to be ported to other arch's?
>
>  
>
Yes, I think if other arch's want same performance as ia32.  Peter
has already ported it to amd64.  But because I don't know other arch's
page fault behavior, for example, is it safe to access a faulting page
again in page fault trap if the page is the one includes kse mailbox ?
is it possible the arch write half of word in a page fault if the faulting
address crosses page boundary ? I need to avoid fetching a not fully
written mailbox address, current I do not check the address range
on ia32, I think I needn't to do so.

David Xu