From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755487AbbE2GgR (ORCPT ); Fri, 29 May 2015 02:36:17 -0400 Received: from mail-pa0-f46.google.com ([209.85.220.46]:36708 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755017AbbE2Gf7 (ORCPT ); Fri, 29 May 2015 02:35:59 -0400 From: Ming Lei To: linux-kernel@vger.kernel.org, Dave Kleikamp Cc: Jens Axboe , Zach Brown , Christoph Hellwig , Maxim Patlasov , Andrew Morton , Alexander Viro , Tejun Heo , Dave Chinner , Ming Lei Subject: [PATCH v4 1/5] fs: kiocb: introduce IOCB_DONT_DIRTY_PAGE flag for direct IO Date: Fri, 29 May 2015 14:35:34 +0800 Message-Id: <1432881338-898-2-git-send-email-ming.lei@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1432881338-898-1-git-send-email-ming.lei@canonical.com> References: <1432881338-898-1-git-send-email-ming.lei@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When direct IO is submitted from kernel, it is often unnecessary to dirty pages, for example of loop, dirtying pages have been considered in the upper filesystem(over loop) side already, and they don't need to be dirtied again. So this patch introduces IOCB_DONT_DIRTY_PAGE flag for direct IO, and other ITER_BVEC and ITER_KVEC cases might benefit from it too, then it can be used for other dio cases which may have different rules to deal with page dirtying. The patch is based on previous Dave's patch. Cc: Dave Kleikamp Signed-off-by: Ming Lei --- fs/direct-io.c | 9 ++++++--- include/linux/fs.h | 1 + 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/fs/direct-io.c b/fs/direct-io.c index 745d234..78964c0 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -120,6 +120,7 @@ struct dio { int page_errors; /* errno from get_user_pages() */ int is_async; /* is IO async ? */ bool defer_completion; /* defer AIO completion to workqueue? */ + bool should_dirty; /* if pages should be dirtied */ int io_error; /* IO error in completion path */ unsigned long refcount; /* direct_io_worker() and bios */ struct bio *bio_list; /* singly linked via bi_private */ @@ -393,7 +394,7 @@ static inline void dio_bio_submit(struct dio *dio, struct dio_submit *sdio) dio->refcount++; spin_unlock_irqrestore(&dio->bio_lock, flags); - if (dio->is_async && dio->rw == READ) + if (dio->is_async && dio->rw == READ && dio->should_dirty) bio_set_pages_dirty(bio); if (sdio->submit_io) @@ -464,13 +465,14 @@ static int dio_bio_complete(struct dio *dio, struct bio *bio) if (!uptodate) dio->io_error = -EIO; - if (dio->is_async && dio->rw == READ) { + if (dio->is_async && dio->rw == READ && dio->should_dirty) { bio_check_pages_dirty(bio); /* transfers ownership */ } else { bio_for_each_segment_all(bvec, bio, i) { struct page *page = bvec->bv_page; - if (dio->rw == READ && !PageCompound(page)) + if (dio->rw == READ && !PageCompound(page) && + dio->should_dirty) set_page_dirty_lock(page); page_cache_release(page); } @@ -1217,6 +1219,7 @@ do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode, spin_lock_init(&dio->bio_lock); dio->refcount = 1; + dio->should_dirty = !(iocb->ki_flags & IOCB_DONT_DIRTY_PAGE); sdio.iter = iter; sdio.final_block_in_request = (offset + iov_iter_count(iter)) >> blkbits; diff --git a/include/linux/fs.h b/include/linux/fs.h index ff4135e..54027ad 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -316,6 +316,7 @@ struct writeback_control; #define IOCB_EVENTFD (1 << 0) #define IOCB_APPEND (1 << 1) #define IOCB_DIRECT (1 << 2) +#define IOCB_DONT_DIRTY_PAGE (1 << 3) struct kiocb { struct file *ki_filp; -- 1.9.1