From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [SCSI] sr: sr_mutex ,multi-drive performance is bad Date: Tue, 29 Oct 2013 08:53:58 -0600 Message-ID: <526FCC06.6070908@kernel.dk> References: Mime-Version: 1.0 Content-Type: text/plain; charset=GB2312 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from merlin.infradead.org ([205.233.59.134]:50661 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751167Ab3J2OyC (ORCPT ); Tue, 29 Oct 2013 10:54:02 -0400 In-Reply-To: Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: yang jun Cc: "linux-scsi@vger.kernel.org" On 10/28/2013 08:30 AM, yang jun wrote: > Dear Mr.Axboe, >=20 > The latest kernel sr_module still uses single mutex,it will serialise > all sr ioctls. Otto Meta had mentioned this on Jan 1st, 2013 . Some > record tools such as growisofs use SG_IO to write data to disc, so if > there are multiple cdroms being recorded at the same time=A3=ACit wil= l be > very slowly. >=20 > I saw sd_module before,it had removed BKL and made "openers" atomic_t > in scsi_disk. Shall we do the same thing to sr_module? That is, to > remove sr_mutex and make "use_count" atomic_t in cdrom_device_info. The same conversion that happened to sd could apply to sr just as easil= y. --=20 Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html