From: Hannes Reinecke <hare@suse.de>
To: dm-devel@redhat.com
Subject: Re: [PATCH 1/1] multipath-tools: Change path checker for IBM IPR devices
Date: Thu, 25 Sep 2014 08:29:56 +0200 [thread overview]
Message-ID: <5423B664.2020007@suse.de> (raw)
In-Reply-To: <20140924195752.289011902@linux.vnet.ibm.com>
On 09/24/2014 09:57 PM, wenxiong@linux.vnet.ibm.com wrote:
> We would like to change path checker to directio for IBM IPR devices.
>
> Signed-off-by: Wen Xiong <wenxiong@linux.vnet.ibm.com>
> ---
> 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,
> },
>
> -- -- dm-devel mailing list dm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel
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
--
Dr. Hannes Reinecke zSeries & Storage
hare@suse.de +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
next prev parent reply other threads:[~2014-09-25 6:29 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-24 19:57 [PATCH 0/1] Change path checker for IPR devices wenxiong
2014-09-24 19:57 ` [PATCH 1/1] multipath-tools: Change path checker for IBM " wenxiong
2014-09-25 6:29 ` Hannes Reinecke [this message]
2014-09-25 16:47 ` Brian King
2014-09-25 16:57 ` [dm-devel] " Christoph Hellwig
2014-09-30 18:05 ` wenxiong
2014-10-01 12:51 ` Christoph Hellwig
2014-10-06 15:22 ` Brian King
2014-10-06 21:50 ` wenxiong
2014-10-21 11:03 ` Christoph Hellwig
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