[mp2] getting rid of the pool argument

As some of you may have followed the discussions here, we are scared to death 
from users using the wrong pools and shooting themselves into the foot. 
Really, what happens is that we take the cool easy Perl and bring back the 
malloc/free issue in a different reincarnation. It's the 'free' part that is 
going to bite us, because memory can be freed w/o a user knowing about it, if 
they have used the wrong pool.

We tried to make things safe and copy the string using perl's malloc, like in 
server_root_relative, which is slowing things down, but sort-of-OK when the 
string is short, and the API is not used heavily. But this copying can't be 
used in other APIs which potentially move mountains of data.

So it all comes to this - can we get rid of the pool argument completely and 
handle it behind the scenes? I think we can do that. This is still raw in my 
head but if we maintain a global variable (similar to 
Apache->request/Apache->server), switching to the right pool (pconf at the 
startup, server pool at child_init/exit, connection pool for filters and 
request pool for requests we may be able to completely get rid of it. If power 
users will want to use a specific pool (e.g. allocating memory from $s pool, 
while inside a request handler), they should be able to change the default 
pool via API and then restore it back (e.g. 
$old_pool=Apache->default_pool($new_pool)).

The question are whether 1) it's a good idea 2) it's not going to hurt the 
performance (remember Apache->request is bad under threads because it uses 
Thread Local Storage, which is supposedly slow).

Also maybe if we assume that there are never too many connections with 
KeepAlive, we could always use $c->pool and never $r->pool, which will 
simplify things a lot, with a bit of memory overhead (but re-usable). Since 
most setups don't use KeepAlive with mod_perl it may just work.

Againg these are just raw ideas. So please throw yours in and let's cook some 
nice meal.

__________________________________________________________________
Stas Bekman            JAm_pH ------> Just Another mod_perl Hacker
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