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 for Android: free password hash cracker in your pocket

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

Message-ID: <4DAC08BB.6060202@fusionio.com>
Date:	Mon, 18 Apr 2011 11:47:39 +0200
From:	Jens Axboe <jaxboe@...ionio.com>
To:	Hannes Reinecke <hare@...e.de>
CC:	device-mapper development <dm-devel@...hat.com>,
	"hch@...radead.org" <hch@...radead.org>,
	"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 2011-04-18 11:40, Hannes Reinecke wrote:
> 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 ...

The multiqueue bits would still have one request_queue, but multiple
queueing structures (I called those blk_queue_ctx, iirc).

-- 
Jens Axboe

--
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/