On 09/24/2014 09:57 PM, wenxiong@xxxxxxxxxxxxxxxxxx wrote:
> We would like to change path checker to directio for IBM IPR devices.
>
> Signed-off-by: Wen Xiong <wenxiong@xxxxxxxxxxxxxxxxxx>
> ---
> libmultipath/hwtable.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> Index: b/libmultipath/hwtable.c
> ===================================================================
> --- a/libmultipath/hwtable.c 2014-09-23 17:39:27.000000000 -0500
> +++ b/libmultipath/hwtable.c 2014-09-23 17:40:31.419667000 -0500
> @@ -630,7 +630,7 @@ static struct hwentry default_hw[] = {
> .pgfailback = -FAILBACK_IMMEDIATE,
> .rr_weight = RR_WEIGHT_NONE,
> .no_path_retry = NO_PATH_RETRY_UNDEF,
> - .checker_name = TUR,
> + .checker_name = DIRECTIO,
> .prio_name = PRIO_ALUA,
> .prio_args = NULL,
> },
>
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Any particular reason for doing so?
Using 'directio' has the drawback that it might stall under higher
load, as it's being added to the _tail_ of the request queue.
TUR is using the 'SG_IO' ioctl, which is added to the head of the
request_queue and hence won't be stalled ...
Cheers,
Hannes
--
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