Re: Possible dcache BUG

[Gene Heskett]

On Friday 06 August 2004 12:58, Linus Torvalds wrote:
>On Fri, 6 Aug 2004, Gene Heskett wrote:
>> Linus, Andrew, should I apply this patch too at the next remake?
>
>Might be worth it, but it's more important to see any oops at all,
> or lack of oopses..
>
>> FWIW, I'm still up (20:38) this morning, and showing plenty (127+
>> megs) of free memory.  No crash, no odd log (other than samba
>> squawking about some option thats been changed & I haven't fixed
>> the smb.conf) so far.
>>
>> I'm beginning to like this test patch, Linus, thanks :)
>
>If the only thing you have done is add the list_del_init() debugging
>patch, then the only thing that has changed is really the access
> patterns to uncached memory.
>
>The original list_del_init() tries to only do a few single _writes_
> to the dentries around it. The added debugging will do _reads_ (and
> thus bring it into the cache) of the dentry pointers of the
> dentries around it.
>
>If that change makes a real difference, I really only see two
>possibilities:
> - there really is a prefetch bug (or possibly, there's a bug in our
>   prefetch fixup code, and the known prefetch bug just triggers the
>   problem indirectly)
> - it just changes the timing enough that whatever bug you hit went
> away.
>
>Now, Chris Shoemaker reported dentry problems on a intel CPU and
> said that wli had seen something too, but I'm wondering whether
> Chris and wli might have been seeing the knfsd/xfs-related dentry
> bug that I found yesterday. So I think the prefetch theory is still
> alive, but we should check with Chris. Chris?
>
>		Linus

I'm still up, a bit over 24 hours now. :)  Free memory is slowly going 
away, I ran mozilla for a while which got rid of about 60 megs, and 
now I see I'm down to 23 free, whereas at the 11 hour up marker I had 
nearly 130 megs free yet.  I've got to go to town, so that will leave 
seti and kmail doing their thing till I get back.  If it goes down, 
hopefully it will record something, unlike the last couple of times.

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
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by Gene Heskett are:
Copyright 2004 by Maurice Eugene Heskett, all rights reserved.
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