Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964983AbWL1IkY (ORCPT ); Thu, 28 Dec 2006 03:40:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965006AbWL1IkW (ORCPT ); Thu, 28 Dec 2006 03:40:22 -0500 Received: from e31.co.us.ibm.com ([32.97.110.149]:38563 "EHLO e31.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964983AbWL1Ijn (ORCPT ); Thu, 28 Dec 2006 03:39:43 -0500 Date: Thu, 28 Dec 2006 14:14:08 +0530 From: Suparna Bhattacharya To: linux-aio@kvack.org, akpm@osdl.org, drepper@redhat.com Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, jakub@redhat.com, mingo@elte.hu Subject: [FSAIO][PATCH 8/8] AIO O_SYNC filesystem write Message-ID: <20061228084408.GH6971@in.ibm.com> Reply-To: suparna@in.ibm.com References: <20061227153855.GA25898@in.ibm.com> <20061228082308.GA4476@in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20061228082308.GA4476@in.ibm.com> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7053 Lines: 212 AIO support for O_SYNC buffered writes, built over O_SYNC-speedup. It uses the tagged radix tree lookups to writeout just the pages pertaining to this request, and retries instead of blocking for writeback to complete on the same range. All the writeout is issued at the time of io submission, and there is a check to make sure that retries skip over straight to the wait_on_page_writeback_range. Limitations: Extending file writes or hole overwrites with O_SYNC may still block because we have yet to convert generic_osync_inode to be asynchronous. For non O_SYNC writes, writeout happens in the background and so typically appears async to the caller except for memory throttling and non-block aligned writes involving read-modify-write. Signed-off-by: Suparna Bhattacharya Acked-by: Ingo Molnar --- include/linux/aio.h | 0 linux-2.6.20-rc1-root/include/linux/fs.h | 13 +++++- linux-2.6.20-rc1-root/mm/filemap.c | 61 +++++++++++++++++++++---------- 3 files changed, 54 insertions(+), 20 deletions(-) diff -puN include/linux/aio.h~aio-fs-write include/linux/aio.h diff -puN mm/filemap.c~aio-fs-write mm/filemap.c --- linux-2.6.20-rc1/mm/filemap.c~aio-fs-write 2006-12-21 08:46:21.000000000 +0530 +++ linux-2.6.20-rc1-root/mm/filemap.c 2006-12-21 08:46:21.000000000 +0530 @@ -239,10 +239,11 @@ EXPORT_SYMBOL(filemap_flush); * @end: ending page index * * Wait for writeback to complete against pages indexed by start->end - * inclusive + * inclusive. In AIO context, this may queue an async notification + * and retry callback and return, instead of blocking the caller. */ -int wait_on_page_writeback_range(struct address_space *mapping, - pgoff_t start, pgoff_t end) +int __wait_on_page_writeback_range(struct address_space *mapping, + pgoff_t start, pgoff_t end, wait_queue_t *wait) { struct pagevec pvec; int nr_pages; @@ -254,20 +255,20 @@ int wait_on_page_writeback_range(struct pagevec_init(&pvec, 0); index = start; - while ((index <= end) && + while (!ret && (index <= end) && (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, PAGECACHE_TAG_WRITEBACK, min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1)) != 0) { unsigned i; - for (i = 0; i < nr_pages; i++) { + for (i = 0; !ret && (i < nr_pages); i++) { struct page *page = pvec.pages[i]; /* until radix tree lookup accepts end_index */ if (page->index > end) continue; - wait_on_page_writeback(page); + ret = __wait_on_page_writeback(page, wait); if (PageError(page)) ret = -EIO; } @@ -303,18 +304,27 @@ int sync_page_range(struct inode *inode, { pgoff_t start = pos >> PAGE_CACHE_SHIFT; pgoff_t end = (pos + count - 1) >> PAGE_CACHE_SHIFT; - int ret; + int ret = 0; if (!mapping_cap_writeback_dirty(mapping) || !count) return 0; + if (in_aio()) { + /* Already issued writeouts for this iocb ? */ + if (kiocbTryRestart(io_wait_to_kiocb(current->io_wait))) + goto do_wait; /* just need to check if done */ + } ret = filemap_fdatawrite_range(mapping, pos, pos + count - 1); - if (ret == 0) { + + if (ret >= 0) { mutex_lock(&inode->i_mutex); ret = generic_osync_inode(inode, mapping, OSYNC_METADATA); mutex_unlock(&inode->i_mutex); } - if (ret == 0) - ret = wait_on_page_writeback_range(mapping, start, end); +do_wait: + if (ret >= 0) { + ret = __wait_on_page_writeback_range(mapping, start, end, + current->io_wait); + } return ret; } EXPORT_SYMBOL(sync_page_range); @@ -335,15 +345,23 @@ int sync_page_range_nolock(struct inode { pgoff_t start = pos >> PAGE_CACHE_SHIFT; pgoff_t end = (pos + count - 1) >> PAGE_CACHE_SHIFT; - int ret; + int ret = 0; if (!mapping_cap_writeback_dirty(mapping) || !count) return 0; + if (in_aio()) { + /* Already issued writeouts for this iocb ? */ + if (kiocbTryRestart(io_wait_to_kiocb(current->io_wait))) + goto do_wait; /* just need to check if done */ + } ret = filemap_fdatawrite_range(mapping, pos, pos + count - 1); - if (ret == 0) + if (ret >= 0) ret = generic_osync_inode(inode, mapping, OSYNC_METADATA); - if (ret == 0) - ret = wait_on_page_writeback_range(mapping, start, end); +do_wait: + if (ret >= 0) { + ret = __wait_on_page_writeback_range(mapping, start, end, + current->io_wait); + } return ret; } EXPORT_SYMBOL(sync_page_range_nolock); @@ -2216,7 +2234,7 @@ zero_length_segment: */ if (likely(status >= 0)) { if (unlikely((file->f_flags & O_SYNC) || IS_SYNC(inode))) { - if (!a_ops->writepage || !is_sync_kiocb(iocb)) + if (!a_ops->writepage) status = generic_osync_inode(inode, mapping, OSYNC_METADATA|OSYNC_DATA); } @@ -2268,7 +2286,10 @@ __generic_file_aio_write_nolock(struct k ocount -= iv->iov_len; /* This segment is no good */ break; } - + if (!is_sync_kiocb(iocb) && kiocbIsRestarted(iocb)) { + /* nothing to transfer, may just need to sync data */ + return ocount; + } count = ocount; pos = *ppos; @@ -2368,8 +2389,10 @@ ssize_t generic_file_aio_write_nolock(st ssize_t err; err = sync_page_range_nolock(inode, mapping, pos, ret); - if (err < 0) + if (err < 0) { ret = err; + iocb->ki_pos = pos; + } } return ret; } @@ -2394,8 +2417,10 @@ ssize_t generic_file_aio_write(struct ki ssize_t err; err = sync_page_range(inode, mapping, pos, ret); - if (err < 0) + if (err < 0) { ret = err; + iocb->ki_pos = pos; + } } return ret; } diff -puN include/linux/fs.h~aio-fs-write include/linux/fs.h --- linux-2.6.20-rc1/include/linux/fs.h~aio-fs-write 2006-12-21 08:46:21.000000000 +0530 +++ linux-2.6.20-rc1-root/include/linux/fs.h 2006-12-21 08:46:21.000000000 +0530 @@ -279,6 +279,7 @@ extern int dir_notify_enable; #include #include #include +#include #include #include @@ -1588,8 +1589,16 @@ extern int filemap_fdatawait(struct addr extern int filemap_write_and_wait(struct address_space *mapping); extern int filemap_write_and_wait_range(struct address_space *mapping, loff_t lstart, loff_t lend); -extern int wait_on_page_writeback_range(struct address_space *mapping, - pgoff_t start, pgoff_t end); +extern int __wait_on_page_writeback_range(struct address_space *mapping, + pgoff_t start, pgoff_t end, wait_queue_t *wait); + +static inline int wait_on_page_writeback_range(struct address_space *mapping, + pgoff_t start, pgoff_t end) +{ + return __wait_on_page_writeback_range(mapping, start, end, + ¤t->__wait.wait); +} + extern int __filemap_fdatawrite_range(struct address_space *mapping, loff_t start, loff_t end, int sync_mode); _ -- Suparna Bhattacharya (suparna@in.ibm.com) Linux Technology Center IBM Software Lab, India - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/