On 04/23/2014 12:29 AM, Weston Andros Adamson wrote:
> This is a step toward allowing pg_test to inform the the
> coalescing code to reduce the size of requests so they may fit in
> whatever scheme the pg_test callback wants to define.
>
> For now, just return the size of the request if there is space, or 0
> if there is not. This shouldn't change any behavior as it acts
> the same as when the pg_test functions returned bool.
>
> Signed-off-by: Weston Andros Adamson <dros@xxxxxxxxxxxxxxx>
> ---
> fs/nfs/blocklayout/blocklayout.c | 16 ++++++++++++----
> fs/nfs/nfs4filelayout.c | 12 +++++++-----
> fs/nfs/objlayout/objio_osd.c | 14 ++++++++++----
> fs/nfs/pagelist.c | 22 +++++++++++++++++++---
> fs/nfs/pnfs.c | 12 +++++++++---
> fs/nfs/pnfs.h | 3 ++-
> include/linux/nfs_page.h | 5 +++--
> 7 files changed, 62 insertions(+), 22 deletions(-)
>
> diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
> index 65d849b..3867976 100644
> --- a/fs/nfs/blocklayout/blocklayout.c
> +++ b/fs/nfs/blocklayout/blocklayout.c
> @@ -1189,13 +1189,17 @@ bl_pg_init_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *req)
> pnfs_generic_pg_init_read(pgio, req);
> }
>
> -static bool
> +/*
> + * Return 0 if @req cannot be coalesced into @pgio, otherwise return the number
> + * of bytes (maximum @req->wb_bytes) that can be coalesced.
> + */
> +static size_t
> bl_pg_test_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
> struct nfs_page *req)
> {
> if (pgio->pg_dreq != NULL &&
> !is_aligned_req(req, SECTOR_SIZE))
> - return false;
> + return 0;
>
> return pnfs_generic_pg_test(pgio, prev, req);
> }
> @@ -1241,13 +1245,17 @@ bl_pg_init_write(struct nfs_pageio_descriptor *pgio, struct nfs_page *req)
> }
> }
>
> -static bool
> +/*
> + * Return 0 if @req cannot be coalesced into @pgio, otherwise return the number
> + * of bytes (maximum @req->wb_bytes) that can be coalesced.
> + */
> +static size_t
> bl_pg_test_write(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
> struct nfs_page *req)
> {
> if (pgio->pg_dreq != NULL &&
> !is_aligned_req(req, PAGE_CACHE_SIZE))
> - return false;
> + return 0;
>
> return pnfs_generic_pg_test(pgio, prev, req);
> }
> diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
> index b6fc8c1..dfc7282 100644
> --- a/fs/nfs/nfs4filelayout.c
> +++ b/fs/nfs/nfs4filelayout.c
> @@ -915,10 +915,10 @@ filelayout_alloc_lseg(struct pnfs_layout_hdr *layoutid,
> /*
> * filelayout_pg_test(). Called by nfs_can_coalesce_requests()
> *
> - * return true : coalesce page
> - * return false : don't coalesce page
> + * Return 0 if @req cannot be coalesced into @pgio, otherwise return the number
> + * of bytes (maximum @req->wb_bytes) that can be coalesced.
> */
> -static bool
> +static size_t
> filelayout_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
> struct nfs_page *req)
> {
> @@ -927,7 +927,7 @@ filelayout_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
>
> if (!pnfs_generic_pg_test(pgio, prev, req) ||
> !nfs_generic_pg_test(pgio, prev, req))
> - return false;
> + return 0;
>
> p_stripe = (u64)req_offset(prev);
> r_stripe = (u64)req_offset(req);
> @@ -936,7 +936,9 @@ filelayout_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
> do_div(p_stripe, stripe_unit);
> do_div(r_stripe, stripe_unit);
>
> - return (p_stripe == r_stripe);
> + if (p_stripe == r_stripe)
> + return req->wb_bytes;
> + return 0;
> }
>
> static void
> diff --git a/fs/nfs/objlayout/objio_osd.c b/fs/nfs/objlayout/objio_osd.c
> index 5457745..c20352a 100644
> --- a/fs/nfs/objlayout/objio_osd.c
> +++ b/fs/nfs/objlayout/objio_osd.c
> @@ -564,14 +564,20 @@ int objio_write_pagelist(struct nfs_write_data *wdata, int how)
> return 0;
> }
>
> -static bool objio_pg_test(struct nfs_pageio_descriptor *pgio,
> +/*
> + * Return 0 if @req cannot be coalesced into @pgio, otherwise return the number
> + * of bytes (maximum @req->wb_bytes) that can be coalesced.
> + */
> +static size_t objio_pg_test(struct nfs_pageio_descriptor *pgio,
> struct nfs_page *prev, struct nfs_page *req)
> {
> if (!pnfs_generic_pg_test(pgio, prev, req))
> - return false;
> + return 0;
>
> - return pgio->pg_count + req->wb_bytes <=
> - (unsigned long)pgio->pg_layout_private;
> + if (pgio->pg_count + req->wb_bytes <=
> + (unsigned long)pgio->pg_layout_private)
> + return req->wb_bytes;
nit
I hate this form please do an "else". This form I use when there
is no symmetry between the options, its like saying "I cut processing
short in this condition"
Thanks
Boaz
> + return 0;
> }
>
> static void objio_init_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *req)
> diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
> index ecd34b7..3c35b9e 100644
> --- a/fs/nfs/pagelist.c
> +++ b/fs/nfs/pagelist.c
> @@ -277,7 +277,17 @@ nfs_wait_on_request(struct nfs_page *req)
> TASK_UNINTERRUPTIBLE);
> }
>
> -bool nfs_generic_pg_test(struct nfs_pageio_descriptor *desc, struct nfs_page *prev, struct nfs_page *req)
> +/*
> + * nfs_generic_pg_test - determine if requests can be coalesced
> + * @desc: pointer to descriptor
> + * @prev: previous request in desc, or NULL
> + * @req: this request
> + *
> + * Returns zero if @req can be coalesced into @desc, otherwise it returns
> + * the size of the request.
> + */
> +size_t 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
> @@ -289,7 +299,9 @@ bool nfs_generic_pg_test(struct nfs_pageio_descriptor *desc, struct nfs_page *pr
> if (desc->pg_bsize < PAGE_SIZE)
> return 0;
>
> - return desc->pg_count + req->wb_bytes <= desc->pg_bsize;
> + if (desc->pg_count + req->wb_bytes <= desc->pg_bsize)
> + return req->wb_bytes;
> + return 0;
> }
> EXPORT_SYMBOL_GPL(nfs_generic_pg_test);
>
> @@ -354,6 +366,8 @@ static bool nfs_can_coalesce_requests(struct nfs_page *prev,
> struct nfs_page *req,
> struct nfs_pageio_descriptor *pgio)
> {
> + size_t size;
> +
> if (!nfs_match_open_context(req->wb_context, prev->wb_context))
> return false;
> if (req->wb_context->dentry->d_inode->i_flock != NULL &&
> @@ -365,7 +379,9 @@ static bool nfs_can_coalesce_requests(struct nfs_page *prev,
> return false;
> if (req_offset(req) != req_offset(prev) + prev->wb_bytes)
> return false;
> - return pgio->pg_ops->pg_test(pgio, prev, req);
> + size = pgio->pg_ops->pg_test(pgio, prev, req);
> + WARN_ON_ONCE(size && size != req->wb_bytes);
> + return size > 0;
> }
>
> /**
> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
> index cb53d45..6201bf6 100644
> --- a/fs/nfs/pnfs.c
> +++ b/fs/nfs/pnfs.c
> @@ -1461,7 +1461,11 @@ pnfs_pageio_init_write(struct nfs_pageio_descriptor *pgio, struct inode *inode,
> nfs_pageio_init(pgio, inode, ld->pg_write_ops, compl_ops, server->wsize, ioflags);
> }
>
> -bool
> +/*
> + * Return 0 if @req cannot be coalesced into @pgio, otherwise return the number
> + * of bytes (maximum @req->wb_bytes) that can be coalesced.
> + */
> +size_t
> pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
> struct nfs_page *req)
> {
> @@ -1482,8 +1486,10 @@ pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
> * first byte that lies outside the pnfs_layout_range. FIXME?
> *
> */
> - return req_offset(req) < end_offset(pgio->pg_lseg->pls_range.offset,
> - pgio->pg_lseg->pls_range.length);
> + if (req_offset(req) < end_offset(pgio->pg_lseg->pls_range.offset,
> + pgio->pg_lseg->pls_range.length))
> + return req->wb_bytes;
> + return 0;
> }
> EXPORT_SYMBOL_GPL(pnfs_generic_pg_test);
>
> diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
> index 0237939..0386d7c 100644
> --- a/fs/nfs/pnfs.h
> +++ b/fs/nfs/pnfs.h
> @@ -192,7 +192,8 @@ int pnfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc);
> void pnfs_generic_pg_init_write(struct nfs_pageio_descriptor *pgio,
> struct nfs_page *req, u64 wb_size);
> int pnfs_generic_pg_writepages(struct nfs_pageio_descriptor *desc);
> -bool pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev, struct nfs_page *req);
> +size_t pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio,
> + struct nfs_page *prev, struct nfs_page *req);
> void pnfs_set_lo_fail(struct pnfs_layout_segment *lseg);
> struct pnfs_layout_segment *pnfs_layout_process(struct nfs4_layoutget *lgp);
> void pnfs_free_lseg_list(struct list_head *tmp_list);
> diff --git a/include/linux/nfs_page.h b/include/linux/nfs_page.h
> index 905809d..214e098 100644
> --- a/include/linux/nfs_page.h
> +++ b/include/linux/nfs_page.h
> @@ -46,7 +46,8 @@ struct nfs_page {
> struct nfs_pageio_descriptor;
> struct nfs_pageio_ops {
> void (*pg_init)(struct nfs_pageio_descriptor *, struct nfs_page *);
> - bool (*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *, struct nfs_page *);
> + size_t (*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *,
> + struct nfs_page *);
> int (*pg_doio)(struct nfs_pageio_descriptor *);
> };
>
> @@ -89,7 +90,7 @@ extern int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
> struct nfs_page *);
> extern void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
> extern void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
> -extern bool nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
> +extern size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
> struct nfs_page *prev,
> struct nfs_page *req);
> extern int nfs_wait_on_request(struct nfs_page *);
>
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