Date: Fri, 03 Sep 2010 09:42:39 +0300 From: Alexander Motin <mav@FreeBSD.org> To: Pawel Jakub Dawidek <pjd@FreeBSD.org> Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, "Justin T. Gibbs" <gibbs@FreeBSD.org>, src-committers@FreeBSD.org Subject: Re: svn commit: r212160 - in head/sys: cam/ata cam/scsi cddl/contrib/opensolaris/uts/common/fs/zfs geom geom/sched kern sys Message-ID: <4C8098DF.4090606@FreeBSD.org> In-Reply-To: <20100903062355.GB1780@garage.freebsd.pl> References: <201009021940.o82JeS8M017537@svn.freebsd.org> <20100902213926.GA2542@garage.freebsd.pl> <4C802028.4040400@FreeBSD.org> <20100903062355.GB1780@garage.freebsd.pl>
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Pawel Jakub Dawidek wrote: > On Thu, Sep 02, 2010 at 04:07:36PM -0600, Justin T. Gibbs wrote: >> On 9/2/2010 3:39 PM, Pawel Jakub Dawidek wrote: >>> Don't you think it would be better to set the flag from within >>> g_io_request()? This way every BIO_FLUSH consumer doesn't have to >>> remember to set it. Or am I missing something? >> I don't feel strongly one way or the other, but I thought that >> g_io_request()'s job was to execute the request and to test invariants, >> not to set policy. Perhaps I misinterpreted it's role. > > Does BIO_FLUSH make sense without BIO_ORDERED? My understanding is that > it doesn't. IMHO it does. If caller manages ordering by waiting for all required writes to complete before submitting BIO_FLUSH. Such technics probably can be more difficult, but IMHO should give more flexibility to disk schedulers under parallel load. > But we still want BIO_ORDERED for use with BIO_WRITE for > write barriers without cache flushing. Sure. -- Alexander Motin
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