linux-nvme.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: hch@lst.de (Christoph Hellwig)
Subject: [PATCH 0/3] Provide more fine grained control over multipathing
Date: Fri, 25 May 2018 16:30:58 +0200	[thread overview]
Message-ID: <20180525143058.GA26391@lst.de> (raw)
In-Reply-To: <20180525142217.zedv7hz6ov6s45qk@linux-x5ow.site>

On Fri, May 25, 2018@04:22:17PM +0200, Johannes Thumshirn wrote:
> But Mike's and Hannes' arguments where reasonable as well, we do not
> know if there are any existing setups we might break leading to
> support calls, which we have to deal with. Personally I don't believe
> there are lot's of existing nvme multipath setups out there, but who
> am I to judge.

I don't think existing setups are very likely, but they absolutely
are a valid reason to support the legacy mode.  That is why we support
the legacy mode using the multipath module option.  Once you move
to a per-subsystem switch you don't support legacy setups, you
create a maze of new setups that we need to keep compatibility
support for forever.

> So can we find a middle ground to this? Or we'll have the
> all-or-nothing situation we have in scsi-mq now again. How about
> tieing the switch to a config option which is off per default?

The middle ground is the module option.  It provides 100% backwards
compatibility if used, but more importantly doesn't create hairy
runtime ABIs that we will have to support forever.

      reply	other threads:[~2018-05-25 14:30 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-25 12:53 [PATCH 0/3] Provide more fine grained control over multipathing Johannes Thumshirn
2018-05-25 12:53 ` [PATCH 1/3] nvme: provide a way to disable nvme mpath per subsystem Johannes Thumshirn
2018-05-25 13:47   ` Mike Snitzer
2018-05-31  8:17   ` Sagi Grimberg
2018-05-25 12:53 ` [PATCH 2/3] nvme multipath: added SUBSYS_ATTR_RW Johannes Thumshirn
2018-05-25 12:53 ` [PATCH 3/3] nvme multipath: add dev_attr_mpath_personality Johannes Thumshirn
2018-05-25 13:05 ` [PATCH 0/3] Provide more fine grained control over multipathing Christoph Hellwig
2018-05-25 13:58   ` Mike Snitzer
2018-05-25 14:12     ` Christoph Hellwig
2018-05-25 14:50       ` Mike Snitzer
2018-05-29  1:19         ` Martin K. Petersen
2018-05-29  3:02           ` Mike Snitzer
2018-05-29  7:18             ` Hannes Reinecke
2018-05-29  7:22             ` Johannes Thumshirn
2018-05-29  8:09               ` Christoph Hellwig
2018-05-29  9:54                 ` Mike Snitzer
2018-05-29 23:27                 ` Mike Snitzer
2018-05-30 19:05                   ` Jens Axboe
2018-05-30 19:59                     ` Mike Snitzer
2018-06-04  6:19                     ` Hannes Reinecke
2018-06-04  7:18                       ` Johannes Thumshirn
2018-06-04 12:59                         ` Christoph Hellwig
2018-06-04 13:27                           ` Mike Snitzer
2018-05-31  2:42               ` Ming Lei
2018-05-30 21:20     ` Sagi Grimberg
2018-05-30 22:02       ` Mike Snitzer
2018-05-31  8:37         ` Sagi Grimberg
2018-05-31 12:37           ` Mike Snitzer
2018-05-31 16:34             ` Christoph Hellwig
2018-06-01  4:11               ` Mike Snitzer
2018-05-31 16:36           ` Christoph Hellwig
2018-05-31 16:33         ` Christoph Hellwig
2018-05-31 18:17           ` Mike Snitzer
2018-06-01  2:40             ` Martin K. Petersen
2018-06-01  4:24               ` Mike Snitzer
2018-06-01 14:09                 ` Martin K. Petersen
2018-06-01 15:21                   ` Mike Snitzer
2018-06-03 11:00                 ` Sagi Grimberg
2018-06-03 16:06                   ` Mike Snitzer
2018-06-04 11:46                     ` Sagi Grimberg
2018-06-04 12:48                       ` Johannes Thumshirn
2018-05-30 22:44       ` Mike Snitzer
2018-05-31  8:51         ` Sagi Grimberg
2018-05-31 12:41           ` Mike Snitzer
2018-06-04 21:58       ` Roland Dreier
2018-06-05  4:42         ` Christoph Hellwig
2018-06-05 22:57           ` Roland Dreier
2018-06-06  9:51             ` Christoph Hellwig
2018-06-06  9:32           ` Sagi Grimberg
2018-06-06  9:50             ` Christoph Hellwig
2018-05-25 14:22   ` Johannes Thumshirn
2018-05-25 14:30     ` Christoph Hellwig [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20180525143058.GA26391@lst.de \
    --to=hch@lst.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).