Date: Tue, 20 Apr 1999 13:59:47 -0700 (PDT) From: Matthew Dillon <dillon@apollo.backplane.com> To: David Greenman <dg@root.com> Cc: John Dyson <dyson@iquest.net>, hackers@FreeBSD.ORG Subject: Re: Directories not VMIO cached at all! Message-ID: <199904202059.NAA00957@apollo.backplane.com> References: <199904202056.NAA11478@implode.root.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
Oof. read the proposal more carefully ... I *AM* creating ficticious
pages. Basically we are removing the functionality from the buffer
cache and putting it in the VM cache directly.
-Matt
Matthew Dillon
<dillon@backplane.com>
:David Greenman
:Co-founder/Principal Architect, The FreeBSD Project - http://www.freebsd.org
:Creator of high-performance Internet servers - http://www.terasolutions.com
:
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