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From Cliff Woolley <cliffwool...@yahoo.com>
Subject Re: freelists: a slightly different approach
Date Wed, 26 Sep 2001 18:42:14 GMT
On Wed, 26 Sep 2001, Ryan Bloom wrote:

> > Will I get lynched if I further suggest putting this thing in the
> > scoreboard?  We've got our conn_rec->id that gives us a handy lookup into
> > the scoreboard, so it seems a logical place to put it.  Or it can just be
> > a separate array, though the dimensions of that array will basically
> > mirror the dimensions of the scoreboard anyway.
> Ummmmmm,  how would that work?  Will you be referencing pointers to
> memory that isn't shared from shared memory?  That seems a bit broken
> to me.

Welllllll, yeah.  But I think I convinced myself it's a bad idea for
performance reasons anyway.  I'm not up to speed on how the locking
mechanisms for the scoreboard work, but it'd suck for one thread to have
to wait around on a scoreboard lock just because of this, when by
definition it's an unshared pointer to unshared data.  (I guess that last
bit alone might disqualify it.)  Oh well, it wouldn't kill us to have a
static array in each MPM that's the appropriate size and to just use that,
indexed by the second half of AP_CHILD_THREAD_FROM_ID.  As long as they
get stored somewhere in Apache and not in apr-util I'm happy.


   Cliff Woolley
   Charlottesville, VA

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