Re: more xcalloc() -> mempool conversions!

On 25 Sep 2000, at 17:52, Adrian Chadd <adrian@creative.net.au> wrote:

>
> This patch is a little rough but it converts a couple of "should have been
> MemPool'ed a long time ago" structures.
>
> Can I get someone to look at this and tell me if its right? If so, I'll
> commit it.
>

 I wanted to ask few clarifications.

 1. Why do we need to always clear alloced memory?
   memPool seems to only use calloc to actually get memory. When it gets
   memory from pools, it doesn't clear it, instead it clears mem always
   during free. Seems weird, although no difference.
   memset adds some overhead, even if very small, it adds up (especially
   on systems with limited CPU-ram bandwidth, like Intel). Do we actually
   need to clear the membuffers? Maybe there would be reason to split
   memPoolAlloc into separate versions: memPoolMalloc and memPoolCalloc?

 2. memPool does not try to align allocations at any size. calloc() does
   it at small sizes (8). Maybe we should add a check that when allocations
   of VM page size granularity occurs, we should use valloc() or memalign()
   As Henrik has noted, this could speedup OS->userspace disk buffering by
   reducing mem-mem copying. Also, if we tune dlmalloc.c to use mmaps for
   allocations > 4-16KB, we could eventually somewhat reduce memory
   fragmentation also.

------------------------------------
 Andres Kroonmaa <andre@online.ee>
 Delfi Online
 Tel: 6501 731, Fax: 6501 708
 Pärnu mnt. 158, Tallinn,
 11317 Estonia
Received on Mon Sep 25 2000 - 04:48:15 MDT