Re: [RFC 0/8] Cpuset aware writeback

[Ethan Solomita <solo@google.com>]

Christoph Lameter wrote:
> On Fri, 20 Apr 2007, Ethan Solomita wrote:
>
>   
> > cpuset_write_dirty_map.htm
> >
> >    In __set_page_dirty_nobuffers() you always call cpuset_update_dirty_nodes()
> > but in __set_page_dirty_buffers() you call it only if page->mapping is still
> > set after locking. Is there a reason for the difference? Also a question not
> > about your patch: why do those functions call __mark_inode_dirty() even if the
> > dirty page has been truncated and mapping == NULL?
> >     
>
> If page->mapping has been cleared then the page was removed from the 
> mapping. __mark_inode_dirty just dirties the inode. If a truncation occurs 
> then the inode was modified.
>   

   You didn't address the first half. Why do the buffers() and 
nobuffers() act differently when calling cpuset_update_dirty_nodes()?

> > cpuset_write_throttle.htm
> >
> >    I noticed that several lines have leading spaces. I didn't check if other
> > patches have the problem too.
> >     
>
> Maybe download the patches? How did those strange .htm endings get 
> appended to the patches?
>   

   Something weird with Firefox, but instead of jumping on me did you 
consider double checking your patches? I just went back, found the text 
versions, and the spaces are still there.e.g.:

+  	unsigned long dirtyable_memory;


> >    In get_dirty_limits(), when cpusets are configd you don't subtract highmen
> > the same way that is done without cpusets. Is this intentional?
> >     
>
> That is something in flux upstream. Linus changed it recently. Do it one 
> way or the other.
>   

   Exactly -- your patch should be consistent and do it the same way as 
whatever your patch is built against. Your patch is built against a 
kernel that subtracts off highmem. "Do it..." are you handing off the 
patch and are done with it?

> >    It seems that dirty_exceeded is still a global punishment across cpusets.
> > Should it be addressed?
> >     
>
> Sure. It would be best if you could place that somehow in a cpuset.
>   

   Again it sounds like you're handing them off. I'm not objecting I 
just hadn't understood that.
   -- Ethan

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