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Date: Mon, 2 Aug 2004 09:57:42 -0700
From: Andrew Morton <akpm@osdl.org>
To: Guillaume Thouvenin <guillaume.thouvenin@bull.net>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [Patch for review] BSD accounting IO stats
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Guillaume Thouvenin <guillaume.thouvenin@bull.net> wrote:
>
> diff -uprN -X dontdiff linux-2.6.8-rc2/drivers/block/ll_rw_blk.c linux-2.6.8-rc2+BSDacct_IO/drivers/block/ll_rw_blk.c
>  --- linux-2.6.8-rc2/drivers/block/ll_rw_blk.c	2004-07-18 06:57:42.000000000 +0200
>  +++ linux-2.6.8-rc2+BSDacct_IO/drivers/block/ll_rw_blk.c	2004-07-27 09:17:33.149321480 +0200
>  @@ -1949,10 +1949,12 @@ void drive_stat_acct(struct request *rq,
>   
>   	if (rw == READ) {
>   		disk_stat_add(rq->rq_disk, read_sectors, nr_sectors);
>  +		current->rblk += nr_sectors;
>   		if (!new_io)
>   			disk_stat_inc(rq->rq_disk, read_merges);
>   	} else if (rw == WRITE) {
>   		disk_stat_add(rq->rq_disk, write_sectors, nr_sectors);
>  +		current->wblk += nr_sectors;
>   		if (!new_io)
>   			disk_stat_inc(rq->rq_disk, write_merges);
>   	}

The `wblk' accounting will be quite wrong - most writes will be accounted
to pdflush, kjournald, etc.