From: Shaohua Li <shaohua.li@intel.com>
To: Wu Fengguang <wfg@linux.intel.com>
Cc: lkml <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Jens Axboe <axboe@kernel.dk>,
Herbert Poetzl <herbert@13thfloor.at>,
Eric Dumazet <eric.dumazet@gmail.com>,
Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [PATCH] fix readahead pipeline break caused by block plug
Date: Wed, 01 Feb 2012 10:25:26 +0800 [thread overview]
Message-ID: <1328063126.21268.54.camel@sli10-conroe> (raw)
In-Reply-To: <20120131103416.GA1661@localhost>
On Tue, 2012-01-31 at 18:34 +0800, Wu Fengguang wrote:
> I'd like to propose a sister patch on the write part. It may not be
> as easy to measure any performance impacts of it, but I'll try.
I did think about it, the write case doesn't matter because we didn't do
real IO there.
I can do another patch to cleanup the code (moving it to direct_io),
sounds ok?
> ---
> Subject: remove plugging at buffered write time
> Date: Tue Jan 31 18:25:48 CST 2012
>
> Buffered write(2) is not directly tied to IO, so no need to handle plug
> in generic_file_aio_write().
>
> CC: Jens Axboe <axboe@kernel.dk>
> CC: Li Shaohua <shaohua.li@intel.com>
> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
> ---
> mm/filemap.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> --- linux-next.orig/mm/filemap.c 2012-01-31 18:23:52.000000000 +0800
> +++ linux-next/mm/filemap.c 2012-01-31 18:25:38.000000000 +0800
> @@ -2267,6 +2267,7 @@ generic_file_direct_write(struct kiocb *
> struct file *file = iocb->ki_filp;
> struct address_space *mapping = file->f_mapping;
> struct inode *inode = mapping->host;
> + struct blk_plug plug;
> ssize_t written;
> size_t write_len;
> pgoff_t end;
> @@ -2301,7 +2302,9 @@ generic_file_direct_write(struct kiocb *
> }
> }
>
> + blk_start_plug(&plug);
> written = mapping->a_ops->direct_IO(WRITE, iocb, iov, pos, *nr_segs);
> + blk_finish_plug(&plug);
>
> /*
> * Finally, try again to invalidate clean pages which might have been
> @@ -2610,13 +2613,11 @@ ssize_t generic_file_aio_write(struct ki
> {
> struct file *file = iocb->ki_filp;
> struct inode *inode = file->f_mapping->host;
> - struct blk_plug plug;
> ssize_t ret;
>
> BUG_ON(iocb->ki_pos != pos);
>
> mutex_lock(&inode->i_mutex);
> - blk_start_plug(&plug);
> ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos);
> mutex_unlock(&inode->i_mutex);
>
> @@ -2627,7 +2628,6 @@ ssize_t generic_file_aio_write(struct ki
> if (err < 0 && ret > 0)
> ret = err;
> }
> - blk_finish_plug(&plug);
> return ret;
> }
> EXPORT_SYMBOL(generic_file_aio_write);
next prev parent reply other threads:[~2012-02-01 2:26 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-31 7:59 [PATCH] fix readahead pipeline break caused by block plug Shaohua Li
2012-01-31 8:36 ` Christoph Hellwig
2012-01-31 8:48 ` Eric Dumazet
2012-01-31 8:50 ` Herbert Poetzl
2012-01-31 8:53 ` Shaohua Li
2012-01-31 9:17 ` Eric Dumazet
2012-01-31 10:20 ` Wu Fengguang
2012-01-31 10:34 ` Wu Fengguang
2012-01-31 10:46 ` Christoph Hellwig
2012-01-31 10:57 ` Wu Fengguang
2012-01-31 11:34 ` Christoph Hellwig
2012-01-31 11:42 ` Wu Fengguang
2012-01-31 11:57 ` Christoph Hellwig
2012-01-31 12:20 ` Wu Fengguang
2012-02-01 2:25 ` Shaohua Li [this message]
2012-01-31 14:47 ` Vivek Goyal
2012-01-31 20:23 ` Vivek Goyal
2012-01-31 22:03 ` Vivek Goyal
2012-01-31 22:13 ` Andrew Morton
2012-01-31 22:22 ` Vivek Goyal
2012-02-01 3:36 ` Vivek Goyal
2012-02-01 7:10 ` Wu Fengguang
2012-02-01 16:01 ` Vivek Goyal
2012-02-01 9:18 ` Christoph Hellwig
2012-02-01 20:10 ` Vivek Goyal
2012-02-01 20:13 ` Jeff Moyer
2012-02-01 20:22 ` Andrew Morton
2012-02-01 7:02 ` Wu Fengguang
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