Date: Wed, 17 Feb 1999 02:23:51 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: luoqi@watermarkgroup.com (Luoqi Chen) Cc: amarks@sarnoff.com, freebsd-hackers@FreeBSD.ORG Subject: Re: Memory-Based VFS Question Message-ID: <199902170223.TAA16780@usr08.primenet.com> In-Reply-To: <199902162144.QAA23030@lor.watermarkgroup.com> from "Luoqi Chen" at Feb 16, 99 04:44:28 pm
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> I don't think VOP_MMAP is used any where, you need to implement
> VOP_GETPAGES and VOP_PUTPAGES instead. The simplest way is to make them
> wrapper functions calling vnode_pager_generic_{get,put}pages, take a look
> at vm/vnode_pager.c
You can't do that for something backed by pages not from a vnode.
If the MFS was on a memory device (like the standard MFS), you could
do this, but not with an MFS that can auto-resize-with-high-watermark.
He will have to implement a non-default VOP_{GET|PUT}PAGES().
This is what is so insidious about having a default vfsops; if the
generic ones would work, it'd be working already, via inheritance,
but the fact that inheritance is taking place at all is not clear
based on the new semantics failing-to-default instead of them
failing-to-notimp.
Terry Lambert
terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.
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