>Hi,
>
>On Fri, 3 Sep 1999 15:41:23 +0200 (CEST), Andrea Arcangeli
><andrea@suse.de> said:
>
>> If your object is to put the bounce-buffer in ll_rw_block and to allow
>> the bigmemory to go into the page-cache IMHO you'll slowdown the
>> system too much. The buffer copies trashes the CPU cache. I thought to
>> do that too (I think I also mentioned that in one of my first emails
>> about bigmem).
>
>We already have patches flying around for cache-bypass bulk memory
>copies on P6. By restricting the page cache to 1G when you have 4G of
>free memory on a large web server, you are also slowing down the system
>too much. :) And of course, in the long term the bounce buffers will
In the envinroments where you _need_ more than 2gigabyte of memory between
anonymous memory and shm memory the use of the bigmem-memory as page-cache
_can't_ improve performances.
>Nonsense! You do only one copy, inside ll_rw_block. You do it before
If you don't show me the code it's hard to understand what are you doing
exactly and what you mean with buffer-bounce. You said you was doing what
my swap code does. But my code replaces the memory completly, it's not
only an helper memory for the I/O.
Andrea
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