On 05/26/2011 12:30 AM, Benny Halevy wrote:
> By default, unless pnfs is used coalesce pages until pg_bsize
> (rsize or wsize) is reached.
>
> pnfs layout drivers define their own pg_test methods that use
> pnfs_generic_pg_test and need to define their own I/O size
> limits (e.g. based on the file stripe size).
>
> Signed-off-by: Benny Halevy <bhalevy@xxxxxxxxxxx>
> ---
> fs/nfs/pagelist.c | 17 +++++++----------
> 1 files changed, 7 insertions(+), 10 deletions(-)
>
> diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
> index 0209ffb..c795660 100644
> --- a/fs/nfs/pagelist.c
> +++ b/fs/nfs/pagelist.c
> @@ -204,6 +204,11 @@ nfs_wait_on_request(struct nfs_page *req)
> TASK_UNINTERRUPTIBLE);
> }
>
> +static bool nfs_generic_pg_test(struct nfs_pageio_descriptor *desc, struct nfs_page *prev, struct nfs_page *req)
> +{
> + return desc->pg_count + req->wb_bytes <= desc->pg_bsize;
> +}
> +
> /**
> * nfs_pageio_init - initialise a page io descriptor
> * @desc: pointer to descriptor
> @@ -229,7 +234,7 @@ void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
> desc->pg_ioflags = io_flags;
> desc->pg_error = 0;
> desc->pg_lseg = NULL;
> - desc->pg_test = NULL;
> + desc->pg_test = nfs_generic_pg_test;
> }
>
> /**
> @@ -259,13 +264,7 @@ static bool nfs_can_coalesce_requests(struct nfs_page *prev,
> return false;
> if (prev->wb_pgbase + prev->wb_bytes != PAGE_CACHE_SIZE)
> return false;
> - /*
> - * Non-whole file layouts need to check that req is inside of
> - * pgio->pg_lseg.
> - */
> - if (pgio->pg_test && !pgio->pg_test(pgio, prev, req))
> - return false;
> - return true;
> + return pgio->pg_test(pgio, prev, req);
> }
>
> /**
> @@ -294,8 +293,6 @@ static int nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc,
> if (desc->pg_bsize < PAGE_SIZE)
> return 0;
What about this part? what is desc->pg_bsize? Is it not what was negotiated with the
MDS? this too should be ignored in PNFS. Maybe just add it to the generic test? me think
Boaz
> newlen += desc->pg_count;
> - if (newlen > desc->pg_bsize)
> - return 0;
> prev = nfs_list_entry(desc->pg_list.prev);
> if (!nfs_can_coalesce_requests(prev, req, desc))
> return 0;
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