Date: Sun, 24 Feb 2002 20:31:24 +0100 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: "Justin T. Gibbs" <gibbs@scsiguy.com> Cc: mjacob@feral.com, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/cam/scsi scsi_cd.c scsi_da.c src/sys/dev/ata ata-disk.c Message-ID: <37516.1014579084@critter.freebsd.dk> In-Reply-To: Your message of "Sun, 24 Feb 2002 12:17:33 MST." <200202241917.g1OJHXI78807@aslan.scsiguy.com>
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In message <200202241917.g1OJHXI78807@aslan.scsiguy.com>, "Justin T. Gibbs" wri tes: >> >>Umm - was this an abortive attempt to use ORDERED Tags? If so, isn't it still >>of use? > >I always assumed it would be used by softupdates to increase the speed >of fsync operations. By using the barrier, you can commit all deps >asynchronously in the correct order with the appropriate barriers and >maximize the device's queue optimizations. In other words: Well, I talked with Kirk, and softupdates relies on the dependencies instead. The problem with BIO_ORDERED is that it totally makes a mess of prioritized I/O queuing because you might conceiveably get a low-pri BIO_ORDERED which has to flush out hi-pri stuff. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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