Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-pa0-f51.google.com ([209.85.220.51]:53987 "EHLO mail-pa0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758459AbaKUKRY (ORCPT ); Fri, 21 Nov 2014 05:17:24 -0500 Received: by mail-pa0-f51.google.com with SMTP id ey11so4622583pad.10 for ; Fri, 21 Nov 2014 02:17:23 -0800 (PST) From: Omar Sandoval To: Alexander Viro , Andrew Morton , Chris Mason , Josef Bacik , linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-nfs@vger.kernel.org, Trond Myklebust , Mel Gorman Cc: Omar Sandoval , Dave Kleikamp , Ming Lei Subject: [PATCH v2 1/5] direct-io: don't dirty ITER_BVEC pages on read Date: Fri, 21 Nov 2014 02:08:27 -0800 Message-Id: In-Reply-To: References: In-Reply-To: References: Sender: linux-nfs-owner@vger.kernel.org List-ID: Reads through the iov_iter infrastructure for kernel pages shouldn't be dirtied by the direct I/O code. This is based on Dave Kleikamp's and Ming Lei's previously posted patches. Cc: Dave Kleikamp Cc: Ming Lei Signed-off-by: Omar Sandoval --- fs/direct-io.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/direct-io.c b/fs/direct-io.c index e181b6b..e542ce4 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -120,6 +120,7 @@ struct dio { spinlock_t bio_lock; /* protects BIO fields below */ int page_errors; /* errno from get_user_pages() */ int is_async; /* is IO async ? */ + int should_dirty; /* should we mark read pages dirty? */ bool defer_completion; /* defer AIO completion to workqueue? */ int io_error; /* IO error in completion path */ unsigned long refcount; /* direct_io_worker() and bios */ @@ -392,7 +393,7 @@ 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) @@ -463,13 +464,13 @@ 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); } @@ -1177,6 +1178,7 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, dio->inode = inode; dio->rw = rw; + dio->should_dirty = !(iter->type & ITER_BVEC); /* * For AIO O_(D)SYNC writes we need to defer completions to a workqueue -- 2.1.3