Re: [patch 1/8] raid5: add a per-stripe lock

[Dan Williams <dan.j.williams@xxxxxxxxx>]

On Mon, Jun 4, 2012 at 1:01 AM, Shaohua Li <shli@xxxxxxxxxx> wrote:
> Add a per-stripe lock to protect stripe specific data, like dev->read,
> written, ... The purpose is to reduce lock contention of conf->device_lock.
>
> Signed-off-by: Shaohua Li <shli@xxxxxxxxxxxx>
> ---
>  drivers/md/raid5.c |   17 +++++++++++++++++
>  drivers/md/raid5.h |    1 +
>  2 files changed, 18 insertions(+)
>
> Index: linux/drivers/md/raid5.c
> ===================================================================
> --- linux.orig/drivers/md/raid5.c       2012-06-01 13:38:54.705210229 +0800
> +++ linux/drivers/md/raid5.c    2012-06-01 13:43:05.594056130 +0800
> @@ -749,6 +749,7 @@ static void ops_complete_biofill(void *s
>
>        /* clear completed biofills */
>        spin_lock_irq(&conf->device_lock);
> +       spin_lock_irq(&sh->stripe_lock);
>        for (i = sh->disks; i--; ) {
>                struct r5dev *dev = &sh->dev[i];
>
> @@ -774,6 +775,7 @@ static void ops_complete_biofill(void *s
>                        }
>                }
>        }
> +       spin_unlock_irq(&sh->stripe_lock);
>        spin_unlock_irq(&conf->device_lock);

Btw... I know this is fixed up in a later patch with the deletion of
device_lock, but bisection may land on this patch which enables irqs a
bit too early.

--
Dan
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