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

From: Zhi Yong Wu
Date: Wed Jul 31 2013 - 10:17:20 EST


On Wed, Jul 31, 2013 at 9:35 PM, Ben Myers <bpm@xxxxxxx> wrote:
> 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@xxxxxxxxxxxxx> wrote:
>> > On Tue, Jul 30, 2013 at 05:59:07PM +0800, zwu.kernel@xxxxxxxxx wrote:
>> >> From: Zhi Yong Wu <wuzhy@xxxxxxxxxxxxxxxxxx>
>> >>
>> >> 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@xxxxxxxxxxxxxxxxxx>
>> >> ---
>> >> 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.
Got it, thanks. I have sent out v3 with this style change.

>
> -Ben



--
Regards,

Zhi Yong Wu
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