Linux-RDMA Archive on lore.kernel.org
 help / color / Atom feed
From: Jason Gunthorpe <jgg@ziepe.ca>
To: Bart Van Assche <bvanassche@acm.org>
Cc: Jack Wang <jinpuwang@gmail.com>,
	linux-block@vger.kernel.org, linux-rdma@vger.kernel.org,
	axboe@kernel.dk, hch@infradead.org, sagi@grimberg.me,
	leon@kernel.org, dledford@redhat.com,
	danil.kipnis@cloud.ionos.com, jinpu.wang@cloud.ionos.com,
	rpenyaev@suse.de
Subject: Re: [PATCH v6 06/25] rtrs: client: main functionality
Date: Thu, 2 Jan 2020 14:23:56 -0400
Message-ID: <20200102182356.GD9282@ziepe.ca> (raw)
In-Reply-To: <e242c08f-68e0-49b7-82e6-924d0124b792@acm.org>

On Mon, Dec 30, 2019 at 03:53:10PM -0800, Bart Van Assche wrote:
> > +	if (req->sg_cnt) {
> > +		if (unlikely(req->dir == DMA_FROM_DEVICE && req->need_inv)) {
> > +			/*
> > +			 * We are here to invalidate RDMA read requests
> > +			 * ourselves.  In normal scenario server should
> > +			 * send INV for all requested RDMA reads, but
> > +			 * we are here, thus two things could happen:
> > +			 *
> > +			 *    1.  this is failover, when errno != 0
> > +			 *        and can_wait == 1,
> > +			 *
> > +			 *    2.  something totally bad happened and
> > +			 *        server forgot to send INV, so we
> > +			 *        should do that ourselves.
> > +			 */
> 
> Please document in the protocol documentation when RDMA reads are used.
> 
> What does "server forgot to send INV" mean?
> 
> Additionally, if I remember correctly Jason considers it very important
> that invalidation happens from the submitting context because otherwise
> the RDMA retry mechanism can't work.

I think my point has usually been you can't use completions on the RQ
to deduce the state of the SQ

But if you are doing inv by posting it on the same SQ then things will
get ordered OK as the HW shouldn't progress the INV until any work
touching that rkey is also concluded.

Jason

  reply index

Thread overview: 89+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-30 10:29 [PATCH v6 00/25] RTRS (former IBTRS) rdma transport library and RNBD (former IBNBD) rdma network block device Jack Wang
2019-12-30 10:29 ` [PATCH v6 01/25] sysfs: export sysfs_remove_file_self() Jack Wang
2019-12-30 10:29 ` [PATCH v6 02/25] rtrs: public interface header to establish RDMA connections Jack Wang
2019-12-30 19:25   ` Bart Van Assche
2020-01-02 13:35     ` Jinpu Wang
2020-01-02 16:36       ` Bart Van Assche
2020-01-02 16:47         ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 03/25] rtrs: private headers with rtrs protocol structs and helpers Jack Wang
2019-12-30 19:48   ` Bart Van Assche
2020-01-02 15:27     ` Jinpu Wang
2020-01-02 17:00       ` Bart Van Assche
2020-01-02 18:26         ` Jason Gunthorpe
2020-01-03 12:31           ` Jinpu Wang
2020-01-03 12:27         ` Jinpu Wang
2019-12-31  0:07   ` Bart Van Assche
2020-01-03 13:48     ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 04/25] rtrs: core: lib functions shared between client and server modules Jack Wang
2019-12-30 22:25   ` Bart Van Assche
2020-01-07 12:22     ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 05/25] rtrs: client: private header with client structs and functions Jack Wang
2019-12-30 22:51   ` Bart Van Assche
2020-01-07 12:39     ` Jinpu Wang
2019-12-30 23:03   ` Bart Van Assche
2020-01-07 12:39     ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 06/25] rtrs: client: main functionality Jack Wang
2019-12-30 23:53   ` Bart Van Assche
2020-01-02 18:23     ` Jason Gunthorpe [this message]
2020-01-03 14:30     ` Jinpu Wang
2020-01-03 16:12       ` Bart Van Assche
2019-12-30 10:29 ` [PATCH v6 07/25] rtrs: client: statistics functions Jack Wang
2020-01-02 21:07   ` Bart Van Assche
2020-01-03 14:39     ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 08/25] rtrs: client: sysfs interface functions Jack Wang
2020-01-02 21:14   ` Bart Van Assche
2020-01-03 14:59     ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 09/25] rtrs: server: private header with server structs and functions Jack Wang
2020-01-02 21:24   ` Bart Van Assche
2020-01-08 16:33     ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 10/25] rtrs: server: main functionality Jack Wang
2020-01-02 22:03   ` Bart Van Assche
2020-01-07 13:19     ` Jinpu Wang
2020-01-07 18:25       ` Jason Gunthorpe
2020-01-10 17:38         ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 11/25] rtrs: server: statistics functions Jack Wang
2020-01-02 22:02   ` Bart Van Assche
2020-01-08 12:55     ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 12/25] rtrs: server: sysfs interface functions Jack Wang
2020-01-02 22:06   ` Bart Van Assche
2020-01-07 14:40     ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 13/25] rtrs: include client and server modules into kernel compilation Jack Wang
2020-01-02 22:11   ` Bart Van Assche
2020-01-03 16:19     ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 14/25] rtrs: a bit of documentation Jack Wang
2019-12-30 23:19   ` Bart Van Assche
2020-01-07 14:48     ` Jinpu Wang
2020-01-02 22:21   ` Bart Van Assche
2020-01-07 15:49     ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 15/25] rnbd: private headers with rnbd protocol structs and helpers Jack Wang
2020-01-02 22:34   ` Bart Van Assche
2020-01-07 16:53     ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 16/25] rnbd: client: private header with client structs and functions Jack Wang
2020-01-02 22:37   ` Bart Van Assche
2020-01-07 17:09     ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 17/25] rnbd: client: main functionality Jack Wang
2020-01-02 23:55   ` Bart Van Assche
2020-01-08 14:22     ` Jinpu Wang
2020-01-10 14:45     ` Jinpu Wang
2020-01-10 15:09       ` Roman Penyaev
2020-01-10 15:29         ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 18/25] rnbd: client: sysfs interface functions Jack Wang
2020-01-03  0:03   ` Bart Van Assche
2020-01-08 13:06     ` Jinpu Wang
2020-01-08 16:39       ` Bart Van Assche
2020-01-08 16:51         ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 19/25] rnbd: server: private header with server structs and functions Jack Wang
2019-12-30 10:29 ` [PATCH v6 20/25] rnbd: server: main functionality Jack Wang
2019-12-30 10:29 ` [PATCH v6 21/25] rnbd: server: functionality for IO submission to file or block dev Jack Wang
2019-12-30 10:29 ` [PATCH v6 22/25] rnbd: server: sysfs interface functions Jack Wang
2019-12-30 10:29 ` [PATCH v6 23/25] rnbd: include client and server modules into kernel compilation Jack Wang
2019-12-30 10:29 ` [PATCH v6 24/25] rnbd: a bit of documentation Jack Wang
2019-12-30 10:29 ` [PATCH v6 25/25] MAINTAINERS: Add maintainers for RNBD/RTRS modules Jack Wang
2019-12-30 12:22   ` Gal Pressman
2020-01-02  8:41     ` Jinpu Wang
2019-12-31  0:11 ` [PATCH v6 00/25] RTRS (former IBTRS) rdma transport library and RNBD (former IBNBD) rdma network block device Bart Van Assche
2020-01-02  8:48   ` Jinpu Wang
2019-12-31  2:39 ` Bart Van Assche
2020-01-02  9:20   ` Jinpu Wang
2020-01-02 18:28   ` Jason Gunthorpe
2020-01-03 12:34     ` Jinpu Wang

Reply instructions:

You may reply publically 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=20200102182356.GD9282@ziepe.ca \
    --to=jgg@ziepe.ca \
    --cc=axboe@kernel.dk \
    --cc=bvanassche@acm.org \
    --cc=danil.kipnis@cloud.ionos.com \
    --cc=dledford@redhat.com \
    --cc=hch@infradead.org \
    --cc=jinpu.wang@cloud.ionos.com \
    --cc=jinpuwang@gmail.com \
    --cc=leon@kernel.org \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-rdma@vger.kernel.org \
    --cc=rpenyaev@suse.de \
    --cc=sagi@grimberg.me \
    /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

Linux-RDMA Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-rdma/0 linux-rdma/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-rdma linux-rdma/ https://lore.kernel.org/linux-rdma \
		linux-rdma@vger.kernel.org
	public-inbox-index linux-rdma

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-rdma


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git