Date: Tue, 20 Apr 1999 13:56:32 -0700 From: David Greenman <dg@root.com> To: Matthew Dillon <dillon@apollo.backplane.com> Cc: John Dyson <dyson@iquest.net>, hackers@FreeBSD.ORG Subject: Re: Directories not VMIO cached at all! Message-ID: <199904202056.NAA11478@implode.root.com> In-Reply-To: Your message of "Tue, 20 Apr 1999 12:28:26 PDT." <199904201928.MAA99383@apollo.backplane.com>
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> All right. Then what about this.... right now vm_page_t's are > required to be PAGE_SIZE'd. > > We change this. We allow vm_page_t's to be sized in multiples of > DEV_BSIZE from 0 through to PAGE_SIZE, but not crossing a physical > page boundry. We get rid of vm_page_t->valid and vm_page_t->dirty and > turn those into PG_VALID and PG_DIRTY flags. we add vm_page_t->size. I prefer the current architecture, actually. Several problems come to mind with your proposed scheme: On for example is problems with handling filesystems with block sizes less than a page. I think there are a lot of other problems, too, but I'm too busy to go looking for them. I don't really see how it fixes anything, either - the wastage for directory blocks will still be there unless you create fictitious pages and/or support offsets within a page (in which case you likely will have page aliasing problems to deal with). Yuck. -DG David Greenman Co-founder/Principal Architect, The FreeBSD Project - http://www.freebsd.org Creator of high-performance Internet servers - http://www.terasolutions.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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