Re: [patch] Prefetching file_read_actor()

Rik van Riel (riel@conectiva.com.br)
Mon, 31 Dec 2001 10:50:15 -0200 (BRST)

On Mon, 31 Dec 2001, Dave Jones wrote:

> diff -urN --exclude-from=/home/davej/.exclude linux-2.5.2-pre5/mm/filemap.c linux-2.5/mm/filemap.c
> --- linux-2.5.2-pre5/mm/filemap.c Sun Dec 16 23:21:24 2001
> +++ linux-2.5/mm/filemap.c Mon Dec 31 03:22:51 2001
> @@ -1570,6 +1570,15 @@
> size = count;
>
> kaddr = kmap(page);
> +
> + if (size > 128) {
> + int i;
> + for(i=0; i<size; i+=64) {
> + prefetch (kaddr+offset);
> + prefetch (kaddr+offset+(L1_CACHE_BYTES*2));

Neat piece of deep magic, please document it ;)

Rik

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