linux-rdma.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Gal Pressman <galpress@amazon.com>
To: Leon Romanovsky <leon@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>,
	Doug Ledford <dledford@redhat.com>, <linux-rdma@vger.kernel.org>,
	Alexander Matushevsky <matua@amazon.com>,
	"Firas JahJah" <firasj@amazon.com>,
	Yossi Leybovich <sleybo@amazon.com>
Subject: Re: [PATCH for-next] RDMA/efa: Move provider specific attributes to ucontext allocation response
Date: Tue, 16 Jun 2020 11:53:11 +0300	[thread overview]
Message-ID: <cba7128b-c427-bc26-5f43-69a22463debc@amazon.com> (raw)
In-Reply-To: <20200616063045.GC2141420@unreal>

On 16/06/2020 9:30, Leon Romanovsky wrote:
> On Mon, Jun 15, 2020 at 10:59:20AM +0300, Gal Pressman wrote:
>> Provider specific attributes which are necessary for the userspace
>> functionality should be part of the alloc ucontext response, not query
>> device. This way a userspace provider could work without issuing a query
>> device verb call. However, the fields will remain in the query device
>> ABI in order to maintain backwards compatibility.
> 
> I don't really understand why "should be ..."? Device properties exposed
> here are per-device and will be equal to all ucontexts, so instead of
> doing one very fast system call, you are "punishing" every ucontext
> call.

I talked about it with Jason in the past, the query device verb is intended to
follow the IBA verb, alloc ucontext should return driver specific data that's
required to operate the user space provider.
A query device call should not be mandatory to load the provider.

Whether it's done through query device/ucontext response, both happen for each
new context call. With this patch, we gather all needed data in one system call
instead of two.

> What is wrong with calling one query_device before allocating any
> ucontext? What are you trying to achieve and what will it give?

How can you call query device without allocating a context?

  reply	other threads:[~2020-06-16  8:53 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-15  7:59 Gal Pressman
2020-06-16  6:30 ` Leon Romanovsky
2020-06-16  8:53   ` Gal Pressman [this message]
2020-06-16  9:38     ` Leon Romanovsky
2020-06-16 17:44       ` Gal Pressman
2020-06-17  4:55         ` Leon Romanovsky
2020-06-17 15:36         ` Jason Gunthorpe
2020-06-17 17:49           ` Gal Pressman
2020-06-18 11:30             ` Gal Pressman
2020-06-25 10:53 ` Gal Pressman

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=cba7128b-c427-bc26-5f43-69a22463debc@amazon.com \
    --to=galpress@amazon.com \
    --cc=dledford@redhat.com \
    --cc=firasj@amazon.com \
    --cc=jgg@ziepe.ca \
    --cc=leon@kernel.org \
    --cc=linux-rdma@vger.kernel.org \
    --cc=matua@amazon.com \
    --cc=sleybo@amazon.com \
    --subject='Re: [PATCH for-next] RDMA/efa: Move provider specific attributes to ucontext allocation response' \
    /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

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).