Re: [PATCH 7/8] SQUASHME: Move a check from nfs_pageio_do_add_request to nfs_generic_pg_test

From: Benny Halevy <bhalevy@panasas.com>
To: Boaz Harrosh <bharrosh@panasas.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>,
	NFS list <linux-nfs@vger.kernel.org>,
	open-osd <osd-dev@open-osd.org>
Subject: Re: [PATCH 7/8] SQUASHME: Move a check from nfs_pageio_do_add_request to nfs_generic_pg_test
Date: Sun, 29 May 2011 20:30:04 +0300	[thread overview]
Message-ID: <4DE2829C.3080208@panasas.com> (raw)
In-Reply-To: <1306665090-1155-1-git-send-email-bharrosh@panasas.com>

On 2011-05-29 13:31, Boaz Harrosh wrote:
> desc->pg_bsize is negotiated with the MDS. But if we are doing
> pnfs-IO it is not relevent.
> 
> While at it cleanup nfs_pageio_do_add_request() in light of the
> less things it needs to do.
> 
> Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
> ---
>  fs/nfs/pagelist.c |   27 +++++++++++++--------------
>  1 files changed, 13 insertions(+), 14 deletions(-)
> 
> diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
> index 36bb67f..624ec2c 100644
> --- a/fs/nfs/pagelist.c
> +++ b/fs/nfs/pagelist.c
> @@ -206,6 +206,16 @@ nfs_wait_on_request(struct nfs_page *req)
>  
>  static bool nfs_generic_pg_test(struct nfs_pageio_descriptor *desc, struct nfs_page *prev, struct nfs_page *req)
>  {
> +	/*
> +	* FIXME: ideally we should be able to coalesce all requests
> +	* that are not block boundary aligned, but currently this
> +	* is problematic for the case of bsize < PAGE_CACHE_SIZE,
> +	* since nfs_flush_multi and nfs_pagein_multi assume you
> +	* can have only one struct nfs_page.
> +	*/

nit: comment indent (will fix)

> +	if (desc->pg_bsize < PAGE_SIZE)
> +		return 0;
> +
>  	return desc->pg_count + req->wb_bytes <= desc->pg_bsize;
>  }
>  
> @@ -279,29 +289,18 @@ static bool nfs_can_coalesce_requests(struct nfs_page *prev,
>  static int nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc,
>  				     struct nfs_page *req)
>  {
> -	size_t newlen = req->wb_bytes;
> -
>  	if (desc->pg_count != 0) {
>  		struct nfs_page *prev;
>  
> -		/*
> -		 * FIXME: ideally we should be able to coalesce all requests
> -		 * that are not block boundary aligned, but currently this
> -		 * is problematic for the case of bsize < PAGE_CACHE_SIZE,
> -		 * since nfs_flush_multi and nfs_pagein_multi assume you
> -		 * can have only one struct nfs_page.
> -		 */
> -		if (desc->pg_bsize < PAGE_SIZE)
> -			return 0;
> -		newlen += desc->pg_count;
>  		prev = nfs_list_entry(desc->pg_list.prev);
>  		if (!nfs_can_coalesce_requests(prev, req, desc))
>  			return 0;
> -	} else
> +	} else {
>  		desc->pg_base = req->wb_pgbase;
> +	}

nit: no need to add the braces here (will remove)

>  	nfs_list_remove_request(req);
>  	nfs_list_add_request(req, &desc->pg_list);
> -	desc->pg_count = newlen;
> +	desc->pg_count += req->wb_bytes;

Thanks!

Benny

>  	return 1;
>  }
>  