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From Norman Tuttle <ntut...@photon.poly.edu>
Subject Re: Dangerous Flood memory model compromises larger runs
Date Fri, 14 Nov 2003 01:37:56 GMT
Thank you for your input (and immediate response), Sander and Cliff. We
hope to use it to help resolve our issues.

-Norman Tuttle ntuttle@opendemand.com

On Thu, 13 Nov 2003, Sander Striker wrote:

> On Thu, 2003-11-13 at 16:26, Cliff Woolley wrote:
> > On Thu, 13 Nov 2003, Norman Tuttle wrote:
> > 
> > > How do the pools define "if possible" in your wording below (i.e., how
> > > would the pool know when to reuse memory)?
> > 
> > It's kind of complicated, so I don't know how well I can explain it off
> > the top of my head (Sander, feel free to jump in here :), but it keeps
> > freelist buckets of varying power-of-two sizes, and if it finds one of the
> > appropriate size, it will use it.
> 
> The allocator keeps freelists of multiples of 4k blocks actually ;)
> 
> > But there are two levels of things going on, too, because the allocator
> > hands out blocks of a certain size, which the pools then divide up into
> > smaller blocks...
> 
> Pools get blocks from the allocator.  Pools then hand out the requested
> memory to the caller.  They hold on to the 'surplus' for the next
> allocation.
> 
> On a pool clear, all used blocks return to the allocator (except for
> the block containing the pool itself (8k)).
> 
> > Oy.
> > 
> > Sander?  Help me out.  :)
> 
> You know what, this question comes up reasonably frequently.  Enough for
> me to start writing a document on this.
> 
> I'll post a URL later on.
> 
> 
> Sander
> 


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