Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755249AbbG3Lgp (ORCPT ); Thu, 30 Jul 2015 07:36:45 -0400 Received: from mail-pa0-f45.google.com ([209.85.220.45]:33664 "EHLO mail-pa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750982AbbG3Lgn (ORCPT ); Thu, 30 Jul 2015 07:36:43 -0400 From: Ming Lei To: Jens Axboe , linux-kernel@vger.kernel.org, Dave Kleikamp Cc: Zach Brown , Christoph Hellwig , Maxim Patlasov , Andrew Morton , Alexander Viro , Tejun Heo , Dave Chinner , Ming Lei Subject: [PATCH v8 1/6] fs: direct-io: don't dirtying pages for ITER_BVEC/ITER_KVEC direct read Date: Thu, 30 Jul 2015 07:36:19 -0400 Message-Id: <1438256184-23645-2-git-send-email-ming.lei@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1438256184-23645-1-git-send-email-ming.lei@canonical.com> References: <1438256184-23645-1-git-send-email-ming.lei@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2647 Lines: 72 When direct read 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 doesn't dirtying pages for ITER_BVEC/ITER_KVEC direct read, and loop should be the 1st case to use ITER_BVEC/ITER_KVEC for direct read I/O. The patch is based on previous Dave's patch. Reviewed-by: Dave Kleikamp Reviewed-by: Christoph Hellwig Signed-off-by: Ming Lei --- fs/direct-io.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/fs/direct-io.c b/fs/direct-io.c index 745d234..07e4b28 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 = (iter->type == ITER_IOVEC); sdio.iter = iter; sdio.final_block_in_request = (offset + iov_iter_count(iter)) >> blkbits; -- 1.9.1 -- 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/