From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: [PATCH 27/27] direct-io: remove random prefetches Date: Sat, 9 Apr 2022 06:50:43 +0200 Message-ID: <20220409045043.23593-28-hch@lst.de> References: <20220409045043.23593-1-hch@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=eypoqjBCbHteIGJMjEE77faduCfiNIsAQ0ydQeu7OQ0=; b=nqH1nBV8lOr2r5wyOjol3g7s8X NGopilIp147x4XNnQqzR5o2YWkY6IO58VVUojmV/ASvSDXVzRQHv+BqUNN8ISkIuVH5Huq+5W/+g6 Fx9NKN7nsNjG6IaaR01B6x8gfqb84JVGaMt2Mch/XsNqmw38mh/kWIOczl1+aSfojYjwvPWnkVT0z zeBYxWSj02o09fDuqh1c1ftABUKI9QxyXU2GCBR2V2aNbgjbyvKcSUL75+QEIgn+hIxNaN3b6eMN+ HQ75AhIB7YFYQ9KIFGF2dUiaHQ4ZLNQzEzLlTd1WzYc4Lz5oFphMfcUxRdKyObtKnqHpozib+pvzE Et/uKlCg==; In-Reply-To: <20220409045043.23593-1-hch@lst.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" To: Jens Axboe Cc: jfs-discussion@lists.sourceforge.net, linux-nvme@lists.infradead.org, virtualization@lists.linux-foundation.org, linux-mm@kvack.org, dm-devel@redhat.com, target-devel@vger.kernel.org, linux-mtd@lists.infradead.org, drbd-dev@lists.linbit.com, linux-s390@vger.kernel.org, linux-nilfs@vger.kernel.org, linux-scsi@vger.kernel.org, cluster-devel@redhat.com, xen-devel@lists.xenproject.org, linux-ext4@vger.kernel.org, linux-um@lists.infradead.org, nbd@other.debian.org, linux-block@vger.kernel.org, linux-bcache@vger.kernel.org, ceph-devel@vger.kernel.org, linux-raid@vger.kernel.org, linux-mmc@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-xfs@vger.kernel.org, ocfs2-devel@oss.oracle.com, linux-fsdevel@vger.kernel.org, ntfs3@lists.linux.dev, linux-btrfs@vger.kernel.org Randomly poking into block device internals for manual prefetches isn't exactly a very maintainable thing to do. And none of the performance criticil direct I/O implementations still use this library function anyway, so just drop it. Signed-off-by: Christoph Hellwig --- fs/direct-io.c | 32 ++++---------------------------- 1 file changed, 4 insertions(+), 28 deletions(-) diff --git a/fs/direct-io.c b/fs/direct-io.c index aef06e607b405..840752006f601 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -1115,11 +1115,10 @@ static inline int drop_refcount(struct dio *dio) * individual fields and will generate much worse code. This is important * for the whole file. */ -static inline ssize_t -do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode, - struct block_device *bdev, struct iov_iter *iter, - get_block_t get_block, dio_iodone_t end_io, - dio_submit_t submit_io, int flags) +ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode, + struct block_device *bdev, struct iov_iter *iter, + get_block_t get_block, dio_iodone_t end_io, + dio_submit_t submit_io, int flags) { unsigned i_blkbits = READ_ONCE(inode->i_blkbits); unsigned blkbits = i_blkbits; @@ -1334,29 +1333,6 @@ do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode, kmem_cache_free(dio_cache, dio); return retval; } - -ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode, - struct block_device *bdev, struct iov_iter *iter, - get_block_t get_block, - dio_iodone_t end_io, dio_submit_t submit_io, - int flags) -{ - /* - * The block device state is needed in the end to finally - * submit everything. Since it's likely to be cache cold - * prefetch it here as first thing to hide some of the - * latency. - * - * Attempt to prefetch the pieces we likely need later. - */ - prefetch(&bdev->bd_disk->part_tbl); - prefetch(bdev->bd_disk->queue); - prefetch((char *)bdev->bd_disk->queue + SMP_CACHE_BYTES); - - return do_blockdev_direct_IO(iocb, inode, bdev, iter, get_block, - end_io, submit_io, flags); -} - EXPORT_SYMBOL(__blockdev_direct_IO); static __init int dio_init(void) -- 2.30.2