Date: Wed, 18 Apr 2001 10:02:04 -0700 (PDT) From: Matt Dillon <dillon@earth.backplane.com> To: Poul-Henning Kamp <phk@critter.freebsd.dk> Cc: Robert Watson <rwatson@FreeBSD.ORG>, Kirk McKusick <mckusick@mckusick.com>, Julian Elischer <julian@elischer.org>, Rik van Riel <riel@conectiva.com.br>, freebsd-hackers@FreeBSD.ORG, David Xu <bsddiy@21cn.com> Subject: Re: vm balance Message-ID: <200104181702.f3IH24s23282@earth.backplane.com> References: <38778.987605692@critter>
next in thread | previous in thread | raw e-mail | index | archive | help
If this will get rid of or clean up the specfs garbage, then I'm all
for it. I would love to see a 'clean' fileops based device interface.
-Matt
:I have not examined the full details of doing the shift yet, but it is
:my impression that it actually will reduce the amount of code
:duplication and special casing.
:
:Basically we will need a new:
:
: struct fileops devfileops = {
: dev_read,
: dev_write,,
: dev_ioctl,
: dev_poll,
: dev_kqfilter,
: dev_stat,
: dev_close
: };
:
:The only places we will need new magic is
: open, which needs to fix the plumbing for us.
: mmap, which may have to be added to the fileops vector.
:
:The amount of special-casing code this would remove from the vnode
:layer is rather astonishing.
:
:If we merger vm-objects and vnodes without taking devices out of the
:mix, we will need even more special-case code for devices.
:
:>The vnode is our abstraction for objects that have
:>address spaces, can be opened/closed and retain a seeking position, can be
:>mapped, have protections, etc, etc.
:
:This is simply not correct Robert, UNIX::sockets also have many of
:those properties, but they're not vnodes...
:
:>Besides which,
:>the kernel knows how to act on vnodes, and there is plenty of precedent
:>for the kernel opening vnodes and keeping around references for its own
:>ends, but there isn't all that much precedent for the kernel doing this
:>using file descriptors :-).
:
:Have you actually examined how FIFO and Sockets work Robert ? :-)
:
:--
: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 freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200104181702.f3IH24s23282>