Re: [PATCH v2] xfs: introduce object readahead to log recovery

[Ben Myers <bpm@sgi.com>]

Hey Zhi,

On Wed, Jul 31, 2013 at 12:07:32PM +0800, Zhi Yong Wu wrote:
> On Wed, Jul 31, 2013 at 7:11 AM, Dave Chinner <david@fromorbit.com> wrote:
> > On Tue, Jul 30, 2013 at 05:59:07PM +0800, zwu.kernel@gmail.com wrote:
> >> From: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
> >>
> >>   It can take a long time to run log recovery operation because it is
> >> single threaded and is bound by read latency. We can find that it took
> >> most of the time to wait for the read IO to occur, so if one object
> >> readahead is introduced to log recovery, it will obviously reduce the
> >> log recovery time.
> >>
> >> Log recovery time stat:
> >>
> >>           w/o this patch        w/ this patch
> >>
> >> real:        0m15.023s             0m7.802s
> >> user:        0m0.001s              0m0.001s
> >> sys:         0m0.246s              0m0.107s
> >>
> >> Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
> >> ---
> >>  fs/xfs/xfs_log_recover.c | 162 +++++++++++++++++++++++++++++++++++++++++++++--
> >>  fs/xfs/xfs_log_recover.h |   2 +
> >>  2 files changed, 159 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
> >> index 7681b19..029826f 100644
> >> --- a/fs/xfs/xfs_log_recover.c
> >> +++ b/fs/xfs/xfs_log_recover.c
> >> @@ -3116,6 +3116,111 @@ xlog_recover_free_trans(
> >>       kmem_free(trans);
> >>  }
> >>
> >> +STATIC void
> >> +xlog_recover_buffer_ra_pass2(
> >> +     struct xlog                     *log,
> >> +     struct xlog_recover_item        *item)
> >> +{
> >> +     xfs_buf_log_format_t    *buf_f = item->ri_buf[0].i_addr;
> >> +     xfs_mount_t             *mp = log->l_mp;
> >
> >         struct xfs_buf_log_format
> >         struct xfs_mount
> Why? *_t is also used in a lot of other places.

It is just a general style preference for using the struct instead of the _t in
the xfs codebase.  Over the course of the past few years they've slowly been
converted in this direction, and we prefer not to add any more _t if it can be
avoided.

-Ben