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From: Sagi Grimberg <sagi@grimberg.me>
To: Roman Penyaev <roman.penyaev@profitbricks.com>,
	Bart Van Assche <Bart.VanAssche@wdc.com>
Cc: "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
	"danil.kipnis@profitbricks.com" <danil.kipnis@profitbricks.com>,
	"hch@infradead.org" <hch@infradead.org>,
	"ogerlitz@mellanox.com" <ogerlitz@mellanox.com>,
	"jinpu.wang@profitbricks.com" <jinpu.wang@profitbricks.com>,
	"axboe@kernel.dk" <axboe@kernel.dk>
Subject: Re: [PATCH 05/24] ibtrs: client: main functionality
Date: Mon, 5 Feb 2018 16:14:43 +0200	[thread overview]
Message-ID: <f0c64f7f-2870-0657-11ec-123a3e99b7a7@grimberg.me> (raw)
In-Reply-To: <CAJrWOzD0YXWGCpR+BTOAJ7HhuVG_cjuomBK7vpGeTYu3H+DE4w@mail.gmail.com>


> Indeed, seems sbitmap can be reused.
> 
> But tags is a part of IBTRS, and is not related to block device at all.  One
> IBTRS connection (session) handles many block devices

we use host shared tag sets for the case of multiple block devices.

> (or any IO producers).

Lets wait until we actually have this theoretical non-block IO
producers..

> With a tag you get a free slot of a buffer where you can read/write, so once
> you've allocated a tag you won't sleep on IO path inside a library.

Same for block tags (given that you don't set the request queue
otherwise)

> Also tag
> helps a lot on IO fail-over to another connection (multipath implementation,
> which is also a part of the transport library, not a block device), where you
> simply reuse the same buffer slot (with a tag in your hands) forwarding IO to
> another RDMA connection.

What is the benefit of this detached architecture? IMO, one reason why
you ended up not reusing a lot of the infrastructure is yielded from the
attempt to support a theoretical different consumer that is not ibnbd.
Did you actually had plans for any other consumers?

Personally, I think you will be much better off with a unified approach
for your block device implementation.

  reply	other threads:[~2018-02-05 14:14 UTC|newest]

Thread overview: 79+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-02 14:08 [PATCH 00/24] InfiniBand Transport (IBTRS) and Network Block Device (IBNBD) Roman Pen
2018-02-02 14:08 ` [PATCH 01/24] ibtrs: public interface header to establish RDMA connections Roman Pen
2018-02-02 14:08 ` [PATCH 02/24] ibtrs: private headers with IBTRS protocol structs and helpers Roman Pen
2018-02-02 14:08 ` [PATCH 03/24] ibtrs: core: lib functions shared between client and server modules Roman Pen
2018-02-05 10:52   ` Sagi Grimberg
2018-02-06 12:01     ` Roman Penyaev
2018-02-06 16:10       ` Jason Gunthorpe
2018-02-07 10:34         ` Roman Penyaev
2018-02-02 14:08 ` [PATCH 04/24] ibtrs: client: private header with client structs and functions Roman Pen
2018-02-05 10:59   ` Sagi Grimberg
2018-02-06 12:23     ` Roman Penyaev
2018-02-02 14:08 ` [PATCH 05/24] ibtrs: client: main functionality Roman Pen
2018-02-02 16:54   ` Bart Van Assche
2018-02-05 13:27     ` Roman Penyaev
2018-02-05 14:14       ` Sagi Grimberg [this message]
2018-02-05 17:05         ` Roman Penyaev
2018-02-05 11:19   ` Sagi Grimberg
2018-02-05 14:19     ` Roman Penyaev
2018-02-05 16:24       ` Bart Van Assche
2018-02-02 14:08 ` [PATCH 06/24] ibtrs: client: statistics functions Roman Pen
2018-02-02 14:08 ` [PATCH 07/24] ibtrs: client: sysfs interface functions Roman Pen
2018-02-05 11:20   ` Sagi Grimberg
2018-02-06 12:28     ` Roman Penyaev
2018-02-02 14:08 ` [PATCH 08/24] ibtrs: server: private header with server structs and functions Roman Pen
2018-02-02 14:08 ` [PATCH 09/24] ibtrs: server: main functionality Roman Pen
2018-02-05 11:29   ` Sagi Grimberg
2018-02-06 12:46     ` Roman Penyaev
2018-02-02 14:08 ` [PATCH 10/24] ibtrs: server: statistics functions Roman Pen
2018-02-02 14:08 ` [PATCH 11/24] ibtrs: server: sysfs interface functions Roman Pen
2018-02-02 14:08 ` [PATCH 12/24] ibtrs: include client and server modules into kernel compilation Roman Pen
2018-02-02 14:08 ` [PATCH 13/24] ibtrs: a bit of documentation Roman Pen
2018-02-02 14:08 ` [PATCH 14/24] ibnbd: private headers with IBNBD protocol structs and helpers Roman Pen
2018-02-02 14:08 ` [PATCH 15/24] ibnbd: client: private header with client structs and functions Roman Pen
2018-02-02 14:08 ` [PATCH 16/24] ibnbd: client: main functionality Roman Pen
2018-02-02 15:11   ` Jens Axboe
2018-02-05 12:54     ` Roman Penyaev
2018-02-02 14:08 ` [PATCH 17/24] ibnbd: client: sysfs interface functions Roman Pen
2018-02-02 14:08 ` [PATCH 18/24] ibnbd: server: private header with server structs and functions Roman Pen
2018-02-02 14:08 ` [PATCH 19/24] ibnbd: server: main functionality Roman Pen
2018-02-02 14:09 ` [PATCH 20/24] ibnbd: server: functionality for IO submission to file or block dev Roman Pen
2018-02-02 14:09 ` [PATCH 21/24] ibnbd: server: sysfs interface functions Roman Pen
2018-02-02 14:09 ` [PATCH 22/24] ibnbd: include client and server modules into kernel compilation Roman Pen
2018-02-02 14:09 ` [PATCH 23/24] ibnbd: a bit of documentation Roman Pen
2018-02-02 15:55   ` Bart Van Assche
2018-02-05 13:03     ` Roman Penyaev
2018-02-05 14:16       ` Sagi Grimberg
2018-02-02 14:09 ` [PATCH 24/24] MAINTAINERS: Add maintainer for IBNBD/IBTRS modules Roman Pen
2018-02-02 16:07 ` [PATCH 00/24] InfiniBand Transport (IBTRS) and Network Block Device (IBNBD) Bart Van Assche
2018-02-02 16:40   ` Doug Ledford
2018-02-05  8:45     ` Jinpu Wang
2018-06-04 12:14     ` Danil Kipnis
2018-02-02 17:05 ` Bart Van Assche
2018-02-05  8:56   ` Jinpu Wang
2018-02-05 11:36     ` Sagi Grimberg
2018-02-05 13:38       ` Danil Kipnis
2018-02-05 14:17         ` Sagi Grimberg
2018-02-05 16:40           ` Danil Kipnis
2018-02-05 18:38             ` Bart Van Assche
2018-02-06  9:44               ` Danil Kipnis
2018-02-06 15:35                 ` Bart Van Assche
2018-02-05 16:16     ` Bart Van Assche
2018-02-05 16:36       ` Jinpu Wang
2018-02-07 16:35       ` Christopher Lameter
2018-02-07 17:18         ` Roman Penyaev
2018-02-07 17:32           ` Bart Van Assche
2018-02-08 17:38             ` Danil Kipnis
2018-02-08 18:09               ` Bart Van Assche
2018-06-04 12:27                 ` Danil Kipnis
2018-02-05 12:16 ` Sagi Grimberg
2018-02-05 12:30   ` Sagi Grimberg
2018-02-07 13:06     ` Roman Penyaev
2018-02-05 16:58   ` Bart Van Assche
2018-02-05 17:16     ` Roman Penyaev
2018-02-05 17:20       ` Bart Van Assche
2018-02-06 11:47         ` Roman Penyaev
2018-02-06 13:12   ` Roman Penyaev
2018-02-06 16:01     ` Bart Van Assche
2018-02-07 12:57       ` Roman Penyaev
2018-02-07 16:35         ` Bart Van Assche

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