linux-kernel - Re: [dm-devel] [PATCH 05/10] block: remove per-queue plugging

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 18 Apr 2011 11:40:28 +0200
From:	Hannes Reinecke <hare@...e.de>
To:	device-mapper development <dm-devel@...hat.com>
Cc:	"hch@...radead.org" <hch@...radead.org>,
	Jens Axboe <jaxboe@...ionio.com>,
	"linux-raid@...r.kernel.org" <linux-raid@...r.kernel.org>,
	Mike Snitzer <snitzer@...hat.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Alasdair G Kergon <agk@...hat.com>
Subject: Re: [dm-devel] [PATCH 05/10] block: remove per-queue plugging

On 04/18/2011 11:19 AM, hch@...radead.org wrote:
> Btw, I really start to wonder if the request level is the right place
> to do this on-stack plugging.  Wouldn't it be better to just plug
> bios in the on-stack queue?  That way we could also stop doing the
> special case merging when adding to the plug list, and leave all the
> merging / I/O schedule logic in the __make_request path.  Probably
> not .39 material, but worth a prototype?
>
> Also what this dicussion brought up is that the block layer data
> structures are highly confusing.  Using a small subset of the
> request_queue also for make_request based driver just doesn't make
> sense.  It seems like we should try to migrate the required state
> to struct gendisk, and submit I/O through a block_device_ops.submit
> method, leaving the request_queue as an internal abstraction for
> the request based drivers.
>
Good point.
It would also help us we the device-mapper redesign agk and myself 
discussed at LSF. Having a block_device_ops.submit function would
allow us remap the actual request queue generically; and we would 
even be able to address more than one request queue, which sounds 
awfully similar to what Jens is trying to do ...

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@...e.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Markus Rex, HRB 16746 (AG Nürnberg)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/