From: Bart Van Assche <bart.vanassche@sandisk.com>
To: Hannes Reinecke <hare@suse.de>,
"Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>, Ewan Milne <emilne@redhat.com>,
James Bottomley <james.bottomley@hansenpartnership.com>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>
Subject: Re: [PATCHv8 20/23] scsi: Add 'access_state' attribute
Date: Mon, 22 Feb 2016 07:34:58 -0800 [thread overview]
Message-ID: <56CB2AA2.9090505@sandisk.com> (raw)
In-Reply-To: <56CAB1E4.9060809@suse.de>
On 02/21/16 22:59, Hannes Reinecke wrote:
> The main reason why I need the 'access_state' attribute is to decouple
> the multipath daemon; at the moment the multipath daemon has to issue
> REPORT TARGET PORT GROUPS frequently to figure out the status, which is
> causing quite some load on the target. When using the 'access_state'
> attribute we would avoid doing I/O for that and have a consistent view,
> both on the kernel and the multipath daemon side.
>
> But it's actually a good thing to have the 'access_state' patch in a
> different series; I've got some more patches converting the remaining
> device_handler to also supply the 'access_state' values.
Hello Hannes,
The above sounds very interesting to me. Will multipathd recognize at
run-time whether or not the kernel supports the sysfs ALUA state
attribute ? Will ALUA state changes be reported through udev or will
multipathd poll the sysfs ALUA state attributes ? And if the netlink
buffer that is used in multipathd to receive udev events overflows
(ENOBUFS), will multipathd resynchronize its state ? As far as I can see
in source file libmultipath/uevent.c today multipathd ignores netlink
buffer overflows.
Thanks,
Bart.
next prev parent reply other threads:[~2016-02-22 15:35 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-19 8:16 [PATCHv8 00/23] ALUA device handler update, part II Hannes Reinecke
2016-02-19 8:16 ` [PATCHv8 01/23] scsi_dh_alua: Pass buffer as function argument Hannes Reinecke
2016-02-19 8:16 ` [PATCHv8 02/23] scsi_dh_alua: separate out alua_stpg() Hannes Reinecke
2016-02-19 8:17 ` [PATCHv8 03/23] scsi_dh_alua: Make stpg synchronous Hannes Reinecke
2016-02-19 8:17 ` [PATCHv8 04/23] scsi_dh_alua: call alua_rtpg() if stpg fails Hannes Reinecke
2016-02-19 8:17 ` [PATCHv8 05/23] scsi_dh_alua: switch to scsi_execute_req_flags() Hannes Reinecke
2016-02-19 8:17 ` [PATCHv8 06/23] scsi_dh_alua: allocate RTPG buffer separately Hannes Reinecke
2016-02-19 8:17 ` [PATCHv8 07/23] scsi_dh_alua: Use separate alua_port_group structure Hannes Reinecke
2016-02-19 8:17 ` [PATCHv8 08/23] scsi_dh_alua: use unique device id Hannes Reinecke
2016-02-19 8:17 ` [PATCHv8 09/23] scsi_dh_alua: simplify alua_initialize() Hannes Reinecke
2016-02-19 8:17 ` [PATCHv8 10/23] revert commit a8e5a2d593cb ("[SCSI] scsi_dh_alua: ALUA handler attach should succeed while TPG is transitioning") Hannes Reinecke
2016-02-19 8:17 ` [PATCHv8 11/23] scsi_dh_alua: move optimize_stpg evaluation Hannes Reinecke
2016-02-19 8:17 ` [PATCHv8 12/23] scsi_dh_alua: remove 'rel_port' from alua_dh_data structure Hannes Reinecke
2016-02-19 8:17 ` [PATCHv8 13/23] scsi_dh_alua: Use workqueue for RTPG Hannes Reinecke
2016-02-19 8:17 ` [PATCHv8 14/23] scsi_dh_alua: Allow workqueue to run synchronously Hannes Reinecke
2016-02-19 8:17 ` [PATCHv8 15/23] scsi_dh_alua: Add new blacklist flag 'BLIST_SYNC_ALUA' Hannes Reinecke
2016-02-19 8:17 ` [PATCHv8 16/23] scsi_dh_alua: Recheck state on unit attention Hannes Reinecke
2016-02-19 8:17 ` [PATCHv8 17/23] scsi_dh_alua: update all port states Hannes Reinecke
2016-02-19 8:17 ` [PATCHv8 18/23] scsi_dh_alua: Send TEST UNIT READY to poll for transitioning Hannes Reinecke
2016-02-19 8:17 ` [PATCHv8 19/23] scsi_dh: add 'rescan' callback Hannes Reinecke
2016-02-19 8:17 ` [PATCHv8 20/23] scsi: Add 'access_state' attribute Hannes Reinecke
2016-02-19 19:10 ` Bart Van Assche
2016-02-20 8:03 ` Hannes Reinecke
2016-02-20 15:16 ` Bart Van Assche
2016-02-21 8:27 ` Hannes Reinecke
2016-02-22 3:05 ` Martin K. Petersen
2016-02-22 4:45 ` Bart Van Assche
2016-02-22 6:59 ` Hannes Reinecke
2016-02-22 15:34 ` Bart Van Assche [this message]
2016-02-23 10:27 ` Hannes Reinecke
2016-02-23 14:12 ` Ewan Milne
2016-02-19 8:17 ` [PATCHv8 21/23] scsi_dh_alua: use common definitions for ALUA state Hannes Reinecke
2016-02-19 8:17 ` [PATCHv8 22/23] scsi_dh_alua: update 'access_state' field Hannes Reinecke
2016-02-19 8:17 ` [PATCHv8 23/23] scsi_dh_alua: Update version to 2.0 Hannes Reinecke
2016-02-24 1:50 ` [PATCHv8 00/23] ALUA device handler update, part II Martin K. Petersen
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