Re: [PATCH] ext3: avoid sending down non-refcounted pages

[Andreas Dilger <adilger@clusterfs.com>]

On Dec 08, 2005  18:09 +0900, FUJITA Tomonori wrote:
> If file systems don't send down non-refcounted pages, it makes life
> much easier for open-iscsi because it uses tcp_sendpage.
> 
> Christoph said that he'll take care of xfs. This patch makes ext3 use
> normal pages instead of kmalloc'ed pages.
> 
> --- a/fs/jbd/transaction.c
> +++ b/fs/jbd/transaction.c
> -				frozen_buffer = jbd_kmalloc(jh2bh(jh)->b_size,
> -							    GFP_NOFS);
> +				frozen_buffer =
> +					(char *) jbd_get_free_page(GFP_NOFS);
> @@ -877,7 +878,7 @@ int journal_get_undo_access(handle_t *ha
> -		committed_data = jbd_kmalloc(jh2bh(jh)->b_size, GFP_NOFS);
> +		committed_data = (char *) jbd_get_free_page(GFP_NOFS);

What happens on 1kB or 2kB block filesystems (i.e. b_size != PAGE_SIZE)?
This will allocate a whole page for each block (which may be considerable
overhead on e.g. a 64kB PAGE_SIZE ia64 or PPC system).

Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.



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