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From: Martin Wilck <mwilck@suse.com>
To: tang.junhui@zte.com.cn,
	Christophe Varoqui <christophe.varoqui@opensvc.com>,
	bmarzins@redhat.com, Hannes Reinecke <hare@suse.de>,
	Bart Van Assche <bart.vanassche@sandisk.com>
Cc: zhang.kai16@zte.com.cn, dm-devel@redhat.com
Subject: Re: Improve processing efficiency for addition and deletion of multipath devices
Date: Mon, 28 Nov 2016 11:28:56 +0100	[thread overview]
Message-ID: <1480328936.23852.10.camel@suse.com> (raw)
In-Reply-To: <OF6C4379F8.661B1ACE-ON48258079.000B15EB-48258079.000CBE4F@zte.com.cn>

On Mon, 2016-11-28 at 10:19 +0800, tang.junhui@zte.com.cn wrote:
> 
> 4.        Proposal 
> Other than processing uevents one by one, uevents which coming from
> the 
> same LUN devices can be mergered to one, and then uevent processing 
> thread only needs to process it once, and it only produces one DM
> addition 
> uevent which could reduce system resource consumption. 
> 

Here comes an idea how to achieve this without a lot of additional
code:

libmultipath already has code to check whether any maps need to be
updated (in coalesce_paths()). Instead of recording uevents, merging
them, and calling ev_add_path() for every affected WWID, it might be
sufficient to set daemon state to DAEMON_CONFIGURE and wake up the main
multipathd thread to call reconfigure(). Then we only need to make sure
that coalesce_paths() really reloads or creates maps only when
necessary. I have some patches here that I made for that purpose, for a
different scenario (multipathd to avoid RELOAD ioctls when it's started
in a scenario where most paths are already set up by udev).

Regards
Martin

-- 
Dr. Martin Wilck <mwilck@suse.com>, Tel. +49 (0)911 74053 2107
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)

--
dm-devel mailing list
dm-devel@redhat.com
https://www.redhat.com/mailman/listinfo/dm-devel

  parent reply	other threads:[~2016-11-28 10:28 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-28  2:19 Improve processing efficiency for addition and deletion of multipath devices tang.junhui
2016-11-28 10:05 ` Hannes Reinecke
2016-11-28 16:07   ` Benjamin Marzinski
2016-11-28 16:26     ` Zdenek Kabelac
2016-11-28 10:06 ` Zdenek Kabelac
2016-11-28 10:42   ` Hannes Reinecke
2016-11-28 11:51     ` Zdenek Kabelac
2016-11-28 12:06       ` Peter Rajnoha
2016-11-28 12:08       ` Hannes Reinecke
2016-11-28 12:23         ` Peter Rajnoha
2016-11-28 12:55         ` Zdenek Kabelac
2016-11-28 17:22         ` Benjamin Marzinski
2016-11-29  9:34           ` Zdenek Kabelac
2016-11-28 10:28 ` Martin Wilck [this message]
2016-11-28 17:31   ` Benjamin Marzinski
2016-11-29  7:52     ` Martin Wilck
2016-11-29 19:21       ` Benjamin Marzinski
2016-11-28 15:25 ` Benjamin Marzinski
2016-11-28 15:37   ` Hannes Reinecke
2016-12-01  1:16     ` tang.junhui
  -- strict thread matches above, loose matches on Subject: below --
2016-11-16  1:46 tang.junhui
2016-11-16  7:53 ` Hannes Reinecke
2016-11-16  8:45   ` tang.junhui
2016-11-16  9:49     ` Martin Wilck
2016-11-17  1:41       ` tang.junhui
2016-11-17 10:48         ` Martin Wilck
2016-11-18  1:02           ` tang.junhui
2016-11-18  7:39             ` Martin Wilck
2016-11-18  8:24               ` tang.junhui
2016-11-18  8:30                 ` Martin Wilck
2016-11-18  8:56                   ` tang.junhui
2016-11-18  9:12                   ` tang.junhui
2016-11-21 18:19                   ` Benjamin Marzinski
2016-11-18 22:26           ` Benjamin Marzinski
2016-11-23  1:08             ` tang.junhui
2016-11-29  9:07               ` Zdenek Kabelac
2016-11-29 10:13                 ` tang.junhui
2016-11-24  9:21             ` Martin Wilck
2016-11-28 18:46               ` Benjamin Marzinski
2016-11-29  6:47                 ` Hannes Reinecke
2016-11-29  8:02                   ` Martin Wilck
2016-11-29  8:10                     ` Zdenek Kabelac
2016-11-29  8:16                       ` Martin Wilck
2016-11-29  8:24                         ` Zdenek Kabelac
2016-11-29 17:25                     ` Benjamin Marzinski
2016-11-29  7:57                 ` Martin Wilck
2016-11-29 17:41                   ` Benjamin Marzinski

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