[Devel] Re: [ckrm-tech] [PATCH] BC: resource beancounters (v4) (added user memory)

[Chandra Seetharaman]

On Fri, 2006-09-08 at 11:22 +0400, Pavel Emelianov wrote:
> Chandra Seetharaman wrote:
> 
> [snip]
> >>>> The question is - whether web server is multithreaded or not...
> >>>> If it is not - then no problem here, you can change current
> >>>> context and new resources will be charged accordingly.
> >>>>
> >>>> And current BC code is _able_ to handle it with _minor_ changes.
> >>>> (One just need to save bc not on mm struct, but rather on vma struct
> >>>> and change mm->bc on set_bc_id()).
> >>>>
> >>>> However, no one (can some one from CKRM team please?) explained so far
> >>>> what to do with threads. Consider the following example.
> >>>>
> >>>> 1. Threaded web server spawns a child to serve a client.
> >>>> 2. child thread touches some pages and they are charged to child BC
> >>>>    (which differs from parent's one)
> >>>> 3. child exits, but since its mm is shared with parent, these pages
> >>>>    stay mapped and charged to child BC.
> >>>>
> >>>> So the question is:  what to do with these pages?
> >>>> - should we recharge them to another BC?
> >>>> - leave them charged?
> >>>>     
> >>>>         
> >>> Leave them charged. It will be charged to the appropriate UBC when they
> >>> touch it again.
> >>>   
> >>>       
> >> Do you mean that page must be re-charged each time someone touches it?
> >>     
> >
> > What I meant is that to leave them charged, and if when they are
> > ummapped and mapped later, charge it to the appropriate BC.
> >   
> In this case multithreaded apache that tries to serve each domain in
> separate BC will fill the memory with BC-s, held by pages allocated
> and mapped in threads.

I do not understand how the memory will be filled with BCs. Can you
explain, please.
-- 

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    Chandra Seetharaman               | Be careful what you choose....
              - sekharan at us.ibm.com   |      .......you may get it.
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