From: Jason Gunthorpe <jgg@ziepe.ca>
To: Haakon Bugge <haakon.bugge@oracle.com>
Cc: Manjunath Patil <manjunath.b.patil@oracle.com>,
Doug Ledford <dledford@redhat.com>,
Leon Romanovsky <leon@kernel.org>,
"valentinef@mellanox.com" <valentinef@mellanox.com>,
"gustavoars@kernel.org" <gustavoars@kernel.org>,
Rama Nichanamatlu <rama.nichanamatlu@oracle.com>,
OFED mailing list <linux-rdma@vger.kernel.org>
Subject: Re: [PATCH v2] IB/ipoib: improve latency in ipoib/cm connection formation
Date: Mon, 19 Apr 2021 14:55:20 -0300 [thread overview]
Message-ID: <20210419175520.GB2047089@ziepe.ca> (raw)
In-Reply-To: <9CE729BE-0E3B-4101-8AE7-60653388639B@oracle.com>
On Wed, Apr 14, 2021 at 10:01:43AM +0000, Haakon Bugge wrote:
> ... and, if you anticipate that the UD QP is using pkey1 at indexX,
> the pkey table table gets updates by the SM so the new entry in
> indexX becomes pkey2, the old pkey1 is now at a new position in the
> table (or not in the table is another case), let's say pkey1 is now
> found at indexY. Now, the connected mode QP will use pkey1 at indexY
> if a dedicated query is performed.
This is the concern.. The SM is really supposed to keep the pkey table
stable, I think if it changes it should trigger some heavy flush.
So just confirm that the heavy flush caused a new pkey index to be
loaded and the UD side gets resynced and we ar egodo
> Then we end up in a split brain, the UD QP uses pkey2 and the RC QPs
> use pkey1. With Manju's patch, they will at least use the same pkey.
Well as you pointed it goes throught he heavy flush and triggers
ipoib_pkey_dev_check_presence() which does update the pkey_index, so
it seems fine.
Applied to for-next
> Not related to this commit; I find it strange that the return value
> of update_child_pkey() is not used in __ipoib_ib_dev_flush().
The second callsite uses it
Jason
prev parent reply other threads:[~2021-04-19 17:55 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-13 18:36 [PATCH v2] IB/ipoib: improve latency in ipoib/cm connection formation Manjunath Patil
2021-04-13 18:42 ` Jason Gunthorpe
2021-04-14 10:01 ` Haakon Bugge
2021-04-19 17:55 ` Jason Gunthorpe [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=20210419175520.GB2047089@ziepe.ca \
--to=jgg@ziepe.ca \
--cc=dledford@redhat.com \
--cc=gustavoars@kernel.org \
--cc=haakon.bugge@oracle.com \
--cc=leon@kernel.org \
--cc=linux-rdma@vger.kernel.org \
--cc=manjunath.b.patil@oracle.com \
--cc=rama.nichanamatlu@oracle.com \
--cc=valentinef@mellanox.com \
/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).