From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bombadil.infradead.org ([198.137.202.133]:54868 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725970AbeKTSRJ (ORCPT ); Tue, 20 Nov 2018 13:17:09 -0500 Date: Mon, 19 Nov 2018 23:49:20 -0800 From: Christoph Hellwig To: Dave Chinner Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk Subject: Re: [PATCH 4/5] splice: increase pipe size in splice_direct_to_actor() Message-ID: <20181120074920.GB25418@infradead.org> References: <20181119211742.8824-1-david@fromorbit.com> <20181119211742.8824-5-david@fromorbit.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181119211742.8824-5-david@fromorbit.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: [adding Al for pipe bits] On Tue, Nov 20, 2018 at 08:17:41AM +1100, Dave Chinner wrote: > From: Dave Chinner > > When copy_file_range() is called on files that have been opened with > O_DIRECT, do_splice_direct() does a manual copy of the range one > pipe buffer at a time. The default is 16 pages, which means on > x86_64 it is limited to 64kB IO. This is extremely slow - 64k > synchrnous read/write will run at maybe 5-10MB/s on a spinning disk > and be seek bound. It will be faster on SSDs, but still very > inefficient. > > Increase the pipe size to the maximum allowed user size so that we > can get decent throughput for this highly sub-optimal copy loop. We > also don't care if changing the pipe size fails - that will just > result in a slower copy. > > Signed-off-by: Dave Chinner > --- > fs/pipe.c | 2 +- > fs/splice.c | 8 ++++++++ > include/linux/pipe_fs_i.h | 1 + > 3 files changed, 10 insertions(+), 1 deletion(-) > > diff --git a/fs/pipe.c b/fs/pipe.c > index bdc5d3c0977d..5885d29cdaa6 100644 > --- a/fs/pipe.c > +++ b/fs/pipe.c > @@ -1025,7 +1025,7 @@ unsigned int round_pipe_size(unsigned long size) > * Allocate a new array of pipe buffers and copy the info over. Returns the > * pipe size if successful, or return -ERROR on error. > */ > -static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long arg) > +long pipe_set_size(struct pipe_inode_info *pipe, unsigned long arg) > { > struct pipe_buffer *bufs; > unsigned int size, nr_pages; > diff --git a/fs/splice.c b/fs/splice.c > index 3553f1956508..64dcc622db8d 100644 > --- a/fs/splice.c > +++ b/fs/splice.c > @@ -34,6 +34,7 @@ > #include > #include > #include > +#include > > #include "internal.h" > > @@ -931,6 +932,13 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, > current->splice_pipe = pipe; > } > > + /* > + * Try to increase the data holding capacity of the pipe so we can do > + * larger IOs. This may not increase the size at all because maximum > + * user pipe size is administrator controlled, but we still should try. > + */ > + pipe_set_size(pipe, pipe_max_size); > + > /* > * Do the splice. > */ > diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h > index 5a3bb3b7c9ad..e7d728e5b5f8 100644 > --- a/include/linux/pipe_fs_i.h > +++ b/include/linux/pipe_fs_i.h > @@ -191,5 +191,6 @@ struct pipe_inode_info *get_pipe_info(struct file *file); > > int create_pipe_files(struct file **, int); > unsigned int round_pipe_size(unsigned long size); > +long pipe_set_size(struct pipe_inode_info *pipe, unsigned long arg); > > #endif > -- > 2.19.1 > ---end quoted text---