From: Trond Myklebust Date: Mon, 2 Apr 2007 18:48:28 -0400 NFS: Another cleanup of the read/write request coalescing code Signed-off-by: Trond Myklebust --- fs/nfs/pagelist.c | 71 +++++++++++++++++++++++++++++++++++++++++++--- fs/nfs/read.c | 62 +++++++++++++++++----------------------- fs/nfs/write.c | 53 +++++++++++++--------------------- include/linux/nfs_page.h | 14 ++++++++- 4 files changed, 125 insertions(+), 75 deletions(-) diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index 7017eb0..5281285 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -225,14 +225,26 @@ out: /** * nfs_pageio_init - initialise a page io descriptor * @desc: pointer to descriptor - * @iosize: io block size + * @inode: pointer to inode + * @doio: pointer to io function + * @bsize: io block size + * @io_flags: extra parameters for the io function */ -void nfs_pageio_init(struct nfs_pageio_descriptor *desc, unsigned int bsize) +void nfs_pageio_init(struct nfs_pageio_descriptor *desc, + struct inode *inode, + int (*doio)(struct inode *, struct list_head *, size_t, int), + unsigned int bsize, + int io_flags) { INIT_LIST_HEAD(&desc->pg_list); + desc->pg_bytes_written = 0; desc->pg_count = 0; desc->pg_bsize = bsize; desc->pg_base = 0; + desc->pg_inode = inode; + desc->pg_doio = doio; + desc->pg_ioflags = io_flags; + desc->pg_error = 0; } /** @@ -265,15 +277,15 @@ static int nfs_can_coalesce_requests(struct nfs_page *prev, } /** - * nfs_pageio_add_request - Attempt to coalesce a request into a page list. + * nfs_pageio_do_add_request - Attempt to coalesce a request into a page list. * @desc: destination io descriptor * @req: request * * 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, - struct nfs_page *req) +static int nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc, + struct nfs_page *req) { size_t newlen = req->wb_bytes; @@ -301,6 +313,46 @@ static int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc, return 1; } +/* + * Helper for nfs_pageio_add_request and nfs_pageio_complete + */ +static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc) +{ + if (!list_empty(&desc->pg_list)) { + int error = desc->pg_doio(desc->pg_inode, + &desc->pg_list, + desc->pg_count, + desc->pg_ioflags); + if (error < 0) + desc->pg_error = error; + else + desc->pg_bytes_written += desc->pg_count; + } + if (list_empty(&desc->pg_list)) { + desc->pg_count = 0; + desc->pg_base = 0; + } +} + +/** + * nfs_pageio_add_request - Attempt to coalesce a request into a page list. + * @desc: destination io descriptor + * @req: request + * + * 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, + struct nfs_page *req) +{ + while (!nfs_pageio_do_add_request(desc, req)) { + nfs_pageio_doio(desc); + if (desc->pg_error < 0) + return 0; + } + return 1; +} + /** * nfs_pageio_add_list - Split coalesced requests out from a list. * @desc: destination io descriptor @@ -320,6 +372,15 @@ void nfs_pageio_add_list(struct nfs_pageio_descriptor *desc, } } +/** + * nfs_pageio_complete - Complete I/O on an nfs_pageio_descriptor + * @desc: pointer to io descriptor + */ +void nfs_pageio_complete(struct nfs_pageio_descriptor *desc) +{ + nfs_pageio_doio(desc); +} + #define NFS_SCAN_MAXENTRIES 16 /** * nfs_scan_dirty - Scan the radix tree for dirty requests diff --git a/fs/nfs/read.c b/fs/nfs/read.c index 97f0f42..0effa74 100644 --- a/fs/nfs/read.c +++ b/fs/nfs/read.c @@ -27,7 +27,8 @@ #define NFSDBG_FACILITY NFSDBG_PAGECACHE -static int nfs_pagein_one(struct list_head *, struct inode *); +static int nfs_pagein_multi(struct inode *, struct list_head *, size_t, int); +static int nfs_pagein_one(struct inode *, struct list_head *, size_t, int); static const struct rpc_call_ops nfs_read_partial_ops; static const struct rpc_call_ops nfs_read_full_ops; @@ -133,7 +134,10 @@ static int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode, memclear_highpage_flush(page, len, PAGE_CACHE_SIZE - len); nfs_list_add_request(new, &one_request); - nfs_pagein_one(&one_request, inode); + if (NFS_SERVER(inode)->rsize < PAGE_CACHE_SIZE) + nfs_pagein_multi(inode, &one_request, len, 0); + else + nfs_pagein_one(inode, &one_request, len, 0); return 0; } @@ -230,7 +234,7 @@ static void nfs_execute_read(struct nfs_read_data *data) * won't see the new data until our attribute cache is updated. This is more * or less conventional NFS client behavior. */ -static int nfs_pagein_multi(struct list_head *head, struct inode *inode) +static int nfs_pagein_multi(struct inode *inode, struct list_head *head, size_t count, int flags) { struct nfs_page *req = nfs_list_entry(head->next); struct page *page = req->wb_page; @@ -242,7 +246,7 @@ static int nfs_pagein_multi(struct list_head *head, struct inode *inode) nfs_list_remove_request(req); - nbytes = req->wb_bytes; + nbytes = count; do { size_t len = min(nbytes,rsize); @@ -258,23 +262,19 @@ static int nfs_pagein_multi(struct list_head *head, struct inode *inode) ClearPageError(page); offset = 0; - nbytes = req->wb_bytes; + nbytes = count; do { data = list_entry(list.next, struct nfs_read_data, pages); list_del_init(&data->pages); data->pagevec[0] = page; - if (nbytes > rsize) { - nfs_read_rpcsetup(req, data, &nfs_read_partial_ops, - rsize, offset); - offset += rsize; - nbytes -= rsize; - } else { - nfs_read_rpcsetup(req, data, &nfs_read_partial_ops, - nbytes, offset); - nbytes = 0; - } + if (nbytes < rsize) + rsize = nbytes; + nfs_read_rpcsetup(req, data, &nfs_read_partial_ops, + rsize, offset); + offset += rsize; + nbytes -= rsize; nfs_execute_read(data); } while (nbytes != 0); @@ -291,30 +291,24 @@ out_bad: return -ENOMEM; } -static int nfs_pagein_one(struct list_head *head, struct inode *inode) +static int nfs_pagein_one(struct inode *inode, struct list_head *head, size_t count, int flags) { struct nfs_page *req; struct page **pages; struct nfs_read_data *data; - unsigned int count; - - if (NFS_SERVER(inode)->rsize < PAGE_CACHE_SIZE) - return nfs_pagein_multi(head, inode); - data = nfs_readdata_alloc(NFS_SERVER(inode)->rsize); + data = nfs_readdata_alloc(count); if (!data) goto out_bad; INIT_LIST_HEAD(&data->pages); pages = data->pagevec; - count = 0; while (!list_empty(head)) { req = nfs_list_entry(head->next); nfs_list_remove_request(req); nfs_list_add_request(req, &data->pages); ClearPageError(req->wb_page); *pages++ = req->wb_page; - count += req->wb_bytes; } req = nfs_list_entry(data->pages.next); @@ -328,22 +322,20 @@ out_bad: } static int -nfs_pagein_list(struct list_head *head, unsigned int rsize) +nfs_pagein_list(struct inode *inode, struct list_head *head, unsigned int rsize) { struct nfs_pageio_descriptor desc; - struct nfs_page *req; unsigned int pages = 0; int error = 0; - while (!list_empty(head)) { - nfs_pageio_init(&desc, rsize); - nfs_pageio_add_list(&desc, head); - req = nfs_list_entry(desc.pg_list.next); - error = nfs_pagein_one(&desc.pg_list, req->wb_context->dentry->d_inode); - if (error < 0) - break; - pages += (desc.pg_count + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; - } + 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) @@ -597,7 +589,7 @@ int nfs_readpages(struct file *filp, struct address_space *mapping, filp->private_data); ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc); if (!list_empty(&head)) { - int err = nfs_pagein_list(&head, server->rsize); + int err = nfs_pagein_list(inode, &head, server->rsize); if (!ret) nfs_add_stats(inode, NFSIOS_READPAGES, err); ret = err; diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 36a8f3c..e533d01 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -835,7 +835,7 @@ static void nfs_execute_write(struct nfs_write_data *data) * Generate multiple small requests to write out a single * contiguous dirty area on one page. */ -static int nfs_flush_multi(struct inode *inode, struct list_head *head, int how) +static int nfs_flush_multi(struct inode *inode, struct list_head *head, size_t count, int how) { struct nfs_page *req = nfs_list_entry(head->next); struct page *page = req->wb_page; @@ -847,7 +847,7 @@ static int nfs_flush_multi(struct inode *inode, struct list_head *head, int how) nfs_list_remove_request(req); - nbytes = req->wb_bytes; + nbytes = count; do { size_t len = min(nbytes, wsize); @@ -862,23 +862,19 @@ static int nfs_flush_multi(struct inode *inode, struct list_head *head, int how) ClearPageError(page); offset = 0; - nbytes = req->wb_bytes; + nbytes = count; do { data = list_entry(list.next, struct nfs_write_data, pages); list_del_init(&data->pages); data->pagevec[0] = page; - if (nbytes > wsize) { - nfs_write_rpcsetup(req, data, &nfs_write_partial_ops, - wsize, offset, how); - offset += wsize; - nbytes -= wsize; - } else { - nfs_write_rpcsetup(req, data, &nfs_write_partial_ops, - nbytes, offset, how); - nbytes = 0; - } + if (nbytes < wsize) + wsize = nbytes; + nfs_write_rpcsetup(req, data, &nfs_write_partial_ops, + wsize, offset, how); + offset += wsize; + nbytes -= wsize; nfs_execute_write(data); } while (nbytes != 0); @@ -904,26 +900,23 @@ out_bad: * This is the case if nfs_updatepage detects a conflicting request * that has been written but not committed. */ -static int nfs_flush_one(struct inode *inode, struct list_head *head, int how) +static int nfs_flush_one(struct inode *inode, struct list_head *head, size_t count, int how) { struct nfs_page *req; struct page **pages; struct nfs_write_data *data; - unsigned int count; - data = nfs_writedata_alloc(NFS_SERVER(inode)->wsize); + data = nfs_writedata_alloc(count); if (!data) goto out_bad; pages = data->pagevec; - count = 0; while (!list_empty(head)) { req = nfs_list_entry(head->next); nfs_list_remove_request(req); nfs_list_add_request(req, &data->pages); ClearPageError(req->wb_page); *pages++ = req->wb_page; - count += req->wb_bytes; } req = nfs_list_entry(data->pages.next); @@ -946,28 +939,22 @@ static int nfs_flush_one(struct inode *inode, struct list_head *head, int how) static int nfs_flush_list(struct inode *inode, struct list_head *head, int npages, int how) { struct nfs_pageio_descriptor desc; - int (*flush_one)(struct inode *, struct list_head *, int); int wpages = NFS_SERVER(inode)->wpages; int wsize = NFS_SERVER(inode)->wsize; - int error; - flush_one = nfs_flush_one; - if (wsize < PAGE_CACHE_SIZE) - flush_one = nfs_flush_multi; /* For single writes, FLUSH_STABLE is more efficient */ if (npages <= wpages && npages == NFS_I(inode)->npages && nfs_list_entry(head->next)->wb_bytes <= wsize) how |= FLUSH_STABLE; - do { - nfs_pageio_init(&desc, wsize); - nfs_pageio_add_list(&desc, head); - error = flush_one(inode, &desc.pg_list, how); - if (error < 0) - goto out_err; - } while (!list_empty(head)); - return 0; -out_err: + if (wsize < PAGE_CACHE_SIZE) + nfs_pageio_init(&desc, inode, nfs_flush_multi, wsize, how); + else + nfs_pageio_init(&desc, inode, nfs_flush_one, wsize, how); + nfs_pageio_add_list(&desc, head); + nfs_pageio_complete(&desc); + if (desc.pg_error == 0) + return 0; while (!list_empty(head)) { struct nfs_page *req = nfs_list_entry(head->next); nfs_list_remove_request(req); @@ -975,7 +962,7 @@ out_err: nfs_end_page_writeback(req->wb_page); nfs_clear_page_writeback(req); } - return error; + return desc.pg_error; } /* diff --git a/include/linux/nfs_page.h b/include/linux/nfs_page.h index 3ef8e04..91c7b18 100644 --- a/include/linux/nfs_page.h +++ b/include/linux/nfs_page.h @@ -50,9 +50,15 @@ struct nfs_page { struct nfs_pageio_descriptor { struct list_head pg_list; + unsigned long pg_bytes_written; size_t pg_count; size_t pg_bsize; unsigned int pg_base; + + struct inode *pg_inode; + int (*pg_doio)(struct inode *, struct list_head *, size_t, int); + int pg_ioflags; + int pg_error; }; #define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags)) @@ -71,10 +77,14 @@ extern long nfs_scan_dirty(struct address_space *mapping, struct list_head *dst); extern int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *head, struct list_head *dst, unsigned long idx_start, unsigned int npages); -extern void nfs_pageio_init(struct nfs_pageio_descriptor *desc, - size_t iosize); +extern void nfs_pageio_init(struct nfs_pageio_descriptor *desc, + struct inode *inode, + int (*doio)(struct inode *, struct list_head *, size_t, int), + size_t bsize, + int how); extern void nfs_pageio_add_list(struct nfs_pageio_descriptor *, struct list_head *); +extern void nfs_pageio_complete(struct nfs_pageio_descriptor *desc); extern int nfs_wait_on_request(struct nfs_page *); extern void nfs_unlock_request(struct nfs_page *req); extern int nfs_set_page_writeback_locked(struct nfs_page *req);