Re: [PATCH 13/24] pnfs_submit: read path changeover

Boaz Harrosh
2010-06-09T19:19:21Z

On 06/08/2010 07:19 AM, Fred Isaman wrote:
> Change readpages path to only call LAYOUTGET once.
>
> Signed-off-by: Fred Isaman <iisaman@netapp.com>
> ---
> fs/nfs/pagelist.c | 2 ++
> fs/nfs/pnfs.c | 37 +++++++------------------------------
> fs/nfs/pnfs.h | 25 ++++++++++++++++---------
> 3 files changed, 25 insertions(+), 39 deletions(-)
>
> diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
> index ed647b9..c3e5a1f 100644
> --- a/fs/nfs/pagelist.c
> +++ b/fs/nfs/pagelist.c
> @@ -253,6 +253,8 @@ static int nfs_can_coalesce_requests(struct nfs_page *prev,
> return 0;
> if (prev->wb_pgbase + prev->wb_bytes != PAGE_CACHE_SIZE)
> return 0;
> + if (req->wb_lseg != prev->wb_lseg)
> + return 0;
> #ifdef CONFIG_NFS_V4_1
> if (pgio->pg_test && !pgio->pg_test(pgio, prev, req))
> return 0;
> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
> index 2b5f6fc..692a18e 100644
> --- a/fs/nfs/pnfs.c
> +++ b/fs/nfs/pnfs.c
> @@ -1689,7 +1689,7 @@ pnfs_readpages(struct nfs_read_data *rdata)
> {
> struct nfs_readargs *args = &rdata->args;
> struct inode *inode = rdata->inode;
> - int numpages, status, pgcount, temp;
> + int numpages, pgcount, temp;
> struct nfs_server *nfss = NFS_SERVER(inode);
> struct nfs_inode *nfsi = NFS_I(inode);
> struct pnfs_layout_segment *lseg;
> @@ -1701,19 +1701,8 @@ pnfs_readpages(struct nfs_read_data *rdata)
> args->count,
> args->offset);
>
> - /* Retrieve and set layout if not allready cached */
> - status = _pnfs_update_layout(inode,
> - args->context,
> - args->count,
> - args->offset,
> - IOMODE_READ,
> - &lseg);
> - if (status) {
> - dprintk("%s: Updating layout failed (%d), retry with NFS \n",
> - __func__, status);
> - trypnfs = PNFS_NOT_ATTEMPTED;
> - goto out;
> - }
> + lseg = rdata->req->wb_lseg;
> + get_lseg(lseg);
>
> /* Determine number of pages. */
> pgcount = args->pgbase + args->count;
> @@ -1740,7 +1729,6 @@ pnfs_readpages(struct nfs_read_data *rdata)
> rdata->pdata.lseg = NULL;
> put_lseg(lseg);
> }
> - out:
> dprintk("%s End (trypnfs:%d)\n", __func__, trypnfs);
> return trypnfs;
> }
> @@ -1749,21 +1737,10 @@ enum pnfs_try_status
> _pnfs_try_to_read_data(struct nfs_read_data *data,
> const struct rpc_call_ops *call_ops)
> {
> - struct inode *ino = data->inode;
> - struct nfs_server *nfss = NFS_SERVER(ino);
> -
> - dprintk("--> %s\n", __func__);
> - /* Only create an rpc request if utilizing NFSv4 I/O */
> - if (!pnfs_enabled_sb(nfss) ||
> - !nfss->pnfs_curr_ld->ld_io_ops->read_pagelist) {
> - dprintk("<-- %s: not using pnfs\n", __func__);
> - return PNFS_NOT_ATTEMPTED;
> - } else {
> - dprintk("%s: Utilizing pNFS I/O\n", __func__);
> - data->pdata.call_ops = call_ops;
> - data->pdata.pnfs_error = 0;
> - return pnfs_readpages(data);
> - }

Wahoo, nice stuff Ha

By now this can go into it's only caller.
(And caller de-inlined, what was that all about)

> + dprintk("%s: Utilizing pNFS I/O\n", __func__);
> + data->pdata.call_ops = call_ops;
> + data->pdata.pnfs_error = 0;
> + return pnfs_readpages(data);
> }
>
> enum pnfs_try_status
> diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
> index 6326ed5..816ebe1 100644
> --- a/fs/nfs/pnfs.h
> +++ b/fs/nfs/pnfs.h
> @@ -94,22 +94,29 @@ static inline int pnfs_enabled_sb(struct nfs_server *nfss)
> return nfss->pnfs_curr_ld != NULL;
> }
>
> +static inline void _pnfs_clear_lseg_from_pages(struct list_head *head)
> +{
> + struct nfs_page *req;
> +
> + list_for_each_entry(req, head, wb_list) {
> + put_lseg(req->wb_lseg);
> + req->wb_lseg = NULL;
> + }
> +}
> +
> static inline enum pnfs_try_status
> pnfs_try_to_read_data(struct nfs_read_data *data,
> const struct rpc_call_ops *call_ops)

Don't think this needs to be inline, whats the point?

> {
> - struct inode *inode = data->inode;
> - struct nfs_server *nfss = NFS_SERVER(inode);
> enum pnfs_try_status ret;
>
> - /* FIXME: read_pagelist should probably be mandated */
> - if (PNFS_EXISTS_LDIO_OP(nfss, read_pagelist))
> - ret = _pnfs_try_to_read_data(data, call_ops);
> - else
> - ret = PNFS_NOT_ATTEMPTED;
> -
> + if (!data->req->wb_lseg)
> + return PNFS_NOT_ATTEMPTED;
> + ret = _pnfs_try_to_read_data(data, call_ops);
> if (ret == PNFS_ATTEMPTED)
> - nfs_inc_stats(inode, NFSIOS_PNFS_READ);
> + nfs_inc_stats(data->inode, NFSIOS_PNFS_READ);
> + else
> + _pnfs_clear_lseg_from_pages(&data->pages);
> return ret;
> }
>

Boaz