Re: [PATCH] raid5:Only move IO_THRESHOLD stripes from delay_list to hold_list in raid5_activate_delayed().

[Paul Menzel <paulepanter@users.sourceforge.net>]

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Dear Ma Jian,


thanks for the patch.


Am Freitag, den 06.07.2012, 20:38 +0800 schrieb majianpeng:
> To imporve write performance and as posssible as to achieve full-write,

s,imporve,improve,
s,posssible,possible,

The second part of the sentence is not clear to me.

Maybe: … and to achieve full-write if possible.

> it only fetch IO_THRESHOLD stripes from delay_list to hold_list.

Can you proof the speed up with some benchmarks? That would be awesome.

> Signed-off-by: majianpeng <majianpeng@gmail.com>

Last not least, could you write your first and last names separated by a
space? (I do not know if I separated them correctly.)

Ma Jian Peng (马建朋) <majianpeng@gmail.com>

    $ git config user.name "Ma Jian Peng (马建朋)"

Maybe even pass `--global` to it.

> ---
>  drivers/md/raid5.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> index 04348d7..45308c5 100644
> --- a/drivers/md/raid5.c
> +++ b/drivers/md/raid5.c
> @@ -3662,6 +3662,7 @@ finish:
>  
>  static void raid5_activate_delayed(struct r5conf *conf)
>  {
> +	int count = 0;
>  	if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
>  		while (!list_empty(&conf->delayed_list)) {
>  			struct list_head *l = conf->delayed_list.next;
> @@ -3672,6 +3673,8 @@ static void raid5_activate_delayed(struct r5conf *conf)
>  			if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
>  				atomic_inc(&conf->preread_active_stripes);
>  			list_add_tail(&sh->lru, &conf->hold_list);
> +			if (count++ >= IO_THRESHOLD)
> +				break;
>  		}
>  	}
>  }


Thanks,

Paul

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