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Commit 8b09bee3 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Cleanup for nfs_readpages() 



Do the coalescing of read requests into block sized requests at start of
I/O as we scan through the pages instead of going through a second pass.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent bcb71bba

fs/nfs/pagelist.c

+2 −2
Original line number Diff line number Diff line
@@ -342,7 +342,7 @@ static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc) 
 * Returns true if the request 'req' was successfully coalesced into the

 * existing list of pages 'desc'.

 */

static int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,

int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,

			   struct nfs_page *req)

{

	while (!nfs_pageio_do_add_request(desc, req)) {

fs/nfs/read.c

+15 −32
Original line number Diff line number Diff line
@@ -321,28 +321,6 @@ static int nfs_pagein_one(struct inode *inode, struct list_head *head, size_t co 
	return -ENOMEM;

}



static int

nfs_pagein_list(struct inode *inode, struct list_head *head, unsigned int rsize)

{

	struct nfs_pageio_descriptor desc;

	unsigned int pages = 0;

	int error = 0;



	if (rsize < PAGE_CACHE_SIZE)

		nfs_pageio_init(&desc, inode, nfs_pagein_multi, rsize, 0);

	else

		nfs_pageio_init(&desc, inode, nfs_pagein_one, rsize, 0);



	nfs_pageio_add_list(&desc, head);

	nfs_pageio_complete(&desc);

	pages += (desc.pg_bytes_written + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;



	nfs_async_read_error(head);

	if (error >= 0)

		return pages;

	return error;

}



/*

 * This is the callback from RPC telling us whether a reply was

 * received or some error occurred (timeout or socket shutdown).
@@ -532,7 +510,7 @@ int nfs_readpage(struct file *file, struct page *page) 
}



struct nfs_readdesc {

	struct list_head *head;

	struct nfs_pageio_descriptor *pgio;

	struct nfs_open_context *ctx;

};
@@ -556,19 +534,21 @@ readpage_async_filler(void *data, struct page *page) 
	}

	if (len < PAGE_CACHE_SIZE)

		memclear_highpage_flush(page, len, PAGE_CACHE_SIZE - len);

	nfs_list_add_request(new, desc->head);

	nfs_pageio_add_request(desc->pgio, new);

	return 0;

}



int nfs_readpages(struct file *filp, struct address_space *mapping,

		struct list_head *pages, unsigned nr_pages)

{

	LIST_HEAD(head);

	struct nfs_pageio_descriptor pgio;

	struct nfs_readdesc desc = {

		.head		= &head,

		.pgio = &pgio,

	};

	struct inode *inode = mapping->host;

	struct nfs_server *server = NFS_SERVER(inode);

	size_t rsize = server->rsize;

	unsigned long npages;

	int ret = -ESTALE;



	dprintk("NFS: nfs_readpages (%s/%Ld %d)\n",
@@ -587,13 +567,16 @@ int nfs_readpages(struct file *filp, struct address_space *mapping, 
	} else

		desc.ctx = get_nfs_open_context((struct nfs_open_context *)

				filp->private_data);

	if (rsize < PAGE_CACHE_SIZE)

		nfs_pageio_init(&pgio, inode, nfs_pagein_multi, rsize, 0);

	else

		nfs_pageio_init(&pgio, inode, nfs_pagein_one, rsize, 0);



	ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc);

	if (!list_empty(&head)) {

		int err = nfs_pagein_list(inode, &head, server->rsize);

		if (!ret)

			nfs_add_stats(inode, NFSIOS_READPAGES, err);

			ret = err;

	}



	nfs_pageio_complete(&pgio);

	npages = (pgio.pg_bytes_written + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;

	nfs_add_stats(inode, NFSIOS_READPAGES, npages);

	put_nfs_open_context(desc.ctx);

out:

	return ret;

include/linux/nfs_page.h

+2 −0
Original line number Diff line number Diff line
@@ -82,6 +82,8 @@ extern void nfs_pageio_init(struct nfs_pageio_descriptor *desc, 
			     int (*doio)(struct inode *, struct list_head *, size_t, int),

			     size_t bsize,

			     int how);

extern	int nfs_pageio_add_request(struct nfs_pageio_descriptor *,

				   struct nfs_page *);

extern	void nfs_pageio_add_list(struct nfs_pageio_descriptor *,

				 struct list_head *);

extern	void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);