:
:Julian Elischer wrote:
:> You can mmap() devices and you can mmap files..
:>
:> you cannot mmap FIFOs or sockets.
:>
:> for this reason I think that devices are still well represented by
:> vnodes. If we merged vnodes and vm objects,
:> then if devices were not vnodes, how would you represe
:
:Julian Elischer wrote:
:> Actually there have been times when I did want to mmap a datastream..
:> I think a datastream mapped into a user buffer-space is one of the
:> possible 0-copy methods people sometimes mention.
:
:This is ugly. There are prettier ways of doing it.
:
:-- Terry
Con
Julian Elischer wrote:
> You can mmap() devices and you can mmap files..
>
> you cannot mmap FIFOs or sockets.
>
> for this reason I think that devices are still well represented by
> vnodes. If we merged vnodes and vm objects,
> then if devices were not vnodes, how would you represent
> a vm a
Julian Elischer wrote:
> Actually there have been times when I did want to mmap a datastream..
> I think a datastream mapped into a user buffer-space is one of the
> possible 0-copy methods people sometimes mention.
This is ugly. There are prettier ways of doing it.
-- Terry
To Unsubscribe: se
:I think we need to remember that we do not always have a
:backing object, nor is a backing object always desirable.
:
:The performance of an mmap'ed file, or swap-backed anonymous
:region is _significantly_ below that of unbacked objects.
:
:-- Terry
This is not true, Terry. There is no pe
Matt Dillon wrote:
>
> This is all preliminary. The question is whether we can
> cover enough bases for this to be viable.
>
> Here is a proposed struct file. Make f_data opaque (or
> more opaque), add f_object, extend fileops (see next
> structure), Added f_vopflags to i
Poul-Henning Kamp wrote:
>
> In message <[EMAIL PROTECTED]>, Kirk
> McKusick writes:
>
> >Every vnode in the system has an associated object.
>
> No: device vnodes dont...
>
> I think the correct solution to that is to move devices away from
> vnodes and into the fdesc layer, just like fifo's
[ ... merging vnode and vm_object_t ... ]
Kirk McKusick wrote:
> Every vnode in the system has an associated object. Every object
> backed by a file (e.g., everything but anonymous objects) has an
> associated vnode. So, the performance of one is pretty tied to the
> performance of the other. Mat
Poul-Henning Kamp wrote:
>
> In message <[EMAIL PROTECTED]>, Matt Dillon writes:
>
> >Actually, all this talk does imply that VM objects should be independant
> >of vnodes. Devices may need to mmap (requiring a VM object), but
> >don't need all the baggage of a vnode. Julian is abs
On Wed, 18 Apr 2001, Poul-Henning Kamp wrote:
> In message <[EMAIL PROTECTED]>, Matt Dillon writes:
> >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.
>
> specfs, aliased vnodes, you name it...
On Wed, Apr 18, 2001 at 10:26:40AM -0700, Julian Elischer wrote:
> Robert Watson wrote:
> >
> > On Wed, 18 Apr 2001, Poul-Henning Kamp wrote:
>
> > As I indicated in my follow-up mail, the statement about seeking was
> > incorrect, that is a property of the open file structure; I believe the
> >
(oops, I forgot to add fo_truncate() to the fileops)
-Matt
To Unsubscribe: send mail to [EMAIL PROTECTED]
with "unsubscribe freebsd-hackers" in the body of the message
This is all preliminary. The question is whether we can cover enough
bases for this to be viable.
Here is a proposed struct file. Make f_data opaque (or more opaque),
add f_object, extend fileops (see next structure), Added f_vopflags
to indicate the presence of a vnode in
In message <[EMAIL PROTECTED]>, Matt Dillon writes:
>Actually, all this talk does imply that VM objects should be independant
>of vnodes. Devices may need to mmap (requiring a VM object), but
>don't need all the baggage of a vnode. Julian is absolutely correct
>there.
Well, y
In message <[EMAIL PROTECTED]>, Matt Dillon writes:
>
>:You can mmap() devices and you can mmap files..
>:
>:you cannot mmap FIFOs or sockets.
>:
>:for this reason I think that devices are still well represented by
>:vnodes. If we merged vnodes and vm objects,
>:then if devices were not vnodes, h
In message <[EMAIL PROTECTED]>, Julian Elischer writes:
>If we merged vnodes and vm objects,
>then if devices were not vnodes, how would you represent
>a vm area that maps a device?
You would use a VM object of course, but it would be a special
kind of VM object, just like today...
--
Poul-Henn
:Does this give you a cache coherence problem if the file system itself
:invokes data writes on files? Consider the UFS quota and extended
:attribute cases: here, the file system will invoke VOP_WRITE() on its
:vnodes to avoid understanding file system internals, so you can have such
:operations
On Wed, 18 Apr 2001, Matt Dillon wrote:
> If a device or file can be mmap()'d, then the VM Object acts as the
> cache layer for the object. We would in fact be able to remove nearly
> *ALL* the caching crap from *ALL* the filesystem code. Filesystem
> code would be responsible
:
:Great. Then we have aliased file pointers...
:that's not a great improvement..
:
:You'd still have to have 'per instance' storage somewhere,
:so that the openned devices could have different permissions, and still
:have them point to common data. so you still need
:aliases, except now it's not
On Wed, 18 Apr 2001, Julian Elischer wrote:
> Poul-Henning Kamp wrote:
> >
> > In message <[EMAIL PROTECTED]>, Matt Dillon writes:
> > >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.
> >
>
Poul-Henning Kamp wrote:
>
> In message <[EMAIL PROTECTED]>, Matt Dillon writes:
> >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.
>
> specfs, aliased vnodes, you name it...
>
> I think the a
:You can mmap() devices and you can mmap files..
:
:you cannot mmap FIFOs or sockets.
:
:for this reason I think that devices are still well represented by
:vnodes. If we merged vnodes and vm objects,
:then if devices were not vnodes, how would you represent
:a vm area that maps a device?
:
:--
Robert Watson wrote:
>
> On Wed, 18 Apr 2001, Poul-Henning Kamp wrote:
> As I indicated in my follow-up mail, the statement about seeking was
> incorrect, that is a property of the open file structure; I believe the
> remainder still holds true. When was the last time you tried mmap'ing or
> see
You can mmap() devices and you can mmap files..
you cannot mmap FIFOs or sockets.
for this reason I think that devices are still well represented by
vnodes. If we merged vnodes and vm objects,
then if devices were not vnodes, how would you represent
a vm area that maps a device?
--
__--
In message <[EMAIL PROTECTED]>, Matt Dillon writes:
>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.
specfs, aliased vnodes, you name it...
I think the aliased vnodes is the single most strong ar
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
On Wed, 18 Apr 2001, Poul-Henning Kamp wrote:
> 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.
..
> The only places we will need new magic is
> open, which needs to
On Wed, 18 Apr 2001, Poul-Henning Kamp wrote:
> >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
>
In message <[EMAIL PROTECTED]>, Rober
t Watson writes:
>
>On Wed, 18 Apr 2001, Poul-Henning Kamp wrote:
>
>> In message <[EMAIL PROTECTED]>, Kirk McKusick writes:
>>
>> >Every vnode in the system has an associated object.
>>
>> No: device vnodes dont...
>>
>> I think the correct solution to th
On Wed, 18 Apr 2001, Robert Watson wrote:
> On Wed, 18 Apr 2001, Poul-Henning Kamp wrote:
> address spaces, can be opened/closed and retain a seeking position, can be
This is what I get for sending messages in the morning after staying up
late -- needless to say, you can ignore the "retain a s
On Wed, 18 Apr 2001, Poul-Henning Kamp wrote:
> In message <[EMAIL PROTECTED]>, Kirk McKusick writes:
>
> >Every vnode in the system has an associated object.
>
> No: device vnodes dont...
>
> I think the correct solution to that is to move devices away from vnodes
> and into the fdesc layer
Dear Matt,
> :
> :Well, if that's the case, yank all uses of v_id from the nfs code,
> :I'll do the namecache and vnodes can be deleted to the joy
> of our users...
> :
>
> If you can yank v_id out from the kern/vfs_cache code, I
> will make similar
> fixes to the NFS code. I am not p
In message <[EMAIL PROTECTED]>, Kirk McKusick writes:
>Every vnode in the system has an associated object.
No: device vnodes dont...
I think the correct solution to that is to move devices away from
vnodes and into the fdesc layer, just like fifo's and sockets.
--
Poul-Henning Kamp | UN
OTECTED]>, David Xu <[EMAIL PROTECTED]>
Subject: Re: vm balance
On Mon, 16 Apr 2001, Kirk McKusick wrote:
> I am still of the opinion that merging VM objects and vnodes would be a
> good idea. Although it would touch a huge number of lines of code, when
> t
:>reference to me. I'm not even sure why they bother to check v_id.
:>The vp reference from an nfsnode is a hard reference.
:>
:
:Well, if that's the case, yank all uses of v_id from the nfs code,
:I'll do the namecache and vnodes can be deleted to the joy of our users...
:
:--
:Poul-Henn
In message <[EMAIL PROTECTED]>, Matt Dillon writes:
>
>:
>:In message <[EMAIL PROTECTED]>, Matt Dillon writes:
>:>
>:>:In message <[EMAIL PROTECTED]>, Alfred Perlstein writes:
>:>:
>:>:>I thought vnodes were in stable storage?
>:>:
>:>:They are, that's the point Matt is not seeing yet.
>:>
>:>
:
:In message <[EMAIL PROTECTED]>, Matt Dillon writes:
:>
:>:In message <[EMAIL PROTECTED]>, Alfred Perlstein writes:
:>:
:>:>I thought vnodes were in stable storage?
:>:
:>:They are, that's the point Matt is not seeing yet.
:>
:>I know vnodes are in stable storage. I'm just saying that NFS
In message <[EMAIL PROTECTED]>, Matt Dillon writes:
>
>:In message <[EMAIL PROTECTED]>, Alfred Perlstein writes:
>:
>:>I thought vnodes were in stable storage?
>:
>:They are, that's the point Matt is not seeing yet.
>
>I know vnodes are in stable storage. I'm just saying that NFS
>is the
:>Note that I really don't care for using stable storeage as a hack
:>to deal with this sort of thing.
:
:Well, I have to admit that it is a pretty smart way of dealing with
:it for remote operations, but the trouble is that it prevents us from
:ever lowering their number again.
:
:If Matt can dev
:In message <[EMAIL PROTECTED]>, Alfred Perlstein writes:
:
:>I thought vnodes were in stable storage?
:
:They are, that's the point Matt is not seeing yet.
I know vnodes are in stable storage. I'm just saying that NFS
is the least of your worries in trying to change that.
In message <[EMAIL PROTECTED]>, Alfred Perlstein writes:
>I thought vnodes were in stable storage?
They are, that's the point Matt is not seeing yet.
>Note that I really don't care for using stable storeage as a hack
>to deal with this sort of thing.
Well, I have to admit that it is a pretty s
* Poul-Henning Kamp <[EMAIL PROTECTED]> [010417 10:56] wrote:
> In message <[EMAIL PROTECTED]>, Matt Dillon writes:
> >:>I don't think NFS relies on vnodes never being freed.
> >:
> >:It does, in some case nfs stashes a vnode pointer and the v_id
> >:value away, and some time later tries to us
:
:In message <[EMAIL PROTECTED]>, Matt Dillon writes:
:>:>I don't think NFS relies on vnodes never being freed.
:>:
:>:It does, in some case nfs stashes a vnode pointer and the v_id
:>:value away, and some time later tries to use that pair to try to
:>:refind the vnode again. If you free vno
In message <[EMAIL PROTECTED]>, Matt Dillon writes:
>:>I don't think NFS relies on vnodes never being freed.
>:
>:It does, in some case nfs stashes a vnode pointer and the v_id
>:value away, and some time later tries to use that pair to try to
>:refind the vnode again. If you free vnodes, it
:>I don't think NFS relies on vnodes never being freed.
:
:It does, in some case nfs stashes a vnode pointer and the v_id
:value away, and some time later tries to use that pair to try to
:refind the vnode again. If you free vnodes, it will still think
:the pointer is a vnode and if junk happ
In message <[EMAIL PROTECTED]>, Matt Dillon writes:
>
>:When I first heard you say this I thought you were off your rockers,
>:but gradually I have come to think that you may be right.
>:
>:I think the task will be easier if we get the vnode/buf relationship
>:untangled a bit first.
>:
>:I may als
:When I first heard you say this I thought you were off your rockers,
:but gradually I have come to think that you may be right.
:
:I think the task will be easier if we get the vnode/buf relationship
:untangled a bit first.
:
:I may also pay off to take vnodes out of diskoperations entirely befo
:I'm interested in this idea, although profess a gaping blind spot in
:expertise in the area of the VM system. However, one of the aspects of
:our VFS that has always concerned me is that use of a single vnode
:simplelock funnels most of the relevant (and performance-sensitive) calls.
:The resul
On Mon, 16 Apr 2001, Kirk McKusick wrote:
> I am still of the opinion that merging VM objects and vnodes would be a
> good idea. Although it would touch a huge number of lines of code, when
> the dust settled, it would simplify some nasty bits of the system. This
> merger is really independent o
In message <[EMAIL PROTECTED]>, Kirk McKusick writes:
>I am still of the opinion that merging VM objects and vnodes would
>be a good idea. Although it would touch a huge number of lines of
>code, when the dust settled, it would simplify some nasty bits of
>the system.
When I first heard you say
On Mon, 16 Apr 2001 04:02:34 -0700,
Alfred Perlstein <[EMAIL PROTECTED]> said:
Alfred> I'm also wondering why you can't track the number of
Alfred> nodes that ought to be cleaned, well, you do, but it doesn't
Alfred> look like it's used:
Alfred> + numcachehv--;
Alfred> +
Date: Tue, 10 Apr 2001 22:14:28 -0700
From: Julian Elischer <[EMAIL PROTECTED]>
To: Rik van Riel <[EMAIL PROTECTED]>
CC: Matt Dillon <[EMAIL PROTECTED]>, David Xu <[EMAIL PROTECTED]>,
[EMAIL PROTECTED], [EMAIL PROTECTED]
Subject: Re: vm balance
In message <[EMAIL PROTECTED]>, Seigo Tanim
ura writes:
>Seigo> http://people.FreeBSD.org/~tanimura/patches/vnrecycle.diff
>
>has been updated and now ready to commit.
Ok, I ran a "cvs update ; make buildworld" here with and without
your patch.
without:
2049.846u 1077.358s 41:29.65 125.6% 5
In message <[EMAIL PROTECTED]>, Seigo Tanim
ura writes:
>Poul-Henning> I'm a bit worried about the amount of work done in the
>Poul-Henning> cache_purgeleafdirs(), considering how often it is called,
>
>Poul-Henning> Do you have measured the performance impact of this to be an
>Poul-Henning> insi
On Mon, 16 Apr 2001 12:36:03 +0200,
Poul-Henning Kamp <[EMAIL PROTECTED]> said:
Poul-Henning> In message <[EMAIL PROTECTED]>,
Seigo Tanim
Poul-Henning> ura writes:
>> Those pieces of work were done in the last weekend, and the patch at
>>
Seigo> http://people.FreeBSD.org/~tanimura/patches/vn
* Seigo Tanimura <[EMAIL PROTECTED]> [010416 03:25] wrote:
> On Fri, 13 Apr 2001 20:08:57 +0900,
> Seigo Tanimura said:
>
> Alfred> Are these changes planned for integration?
>
> Seigo> Yes, but not very soon as there are a few kinds of works that should
> Seigo> be done.
>
> Seigo> One is t
In message <[EMAIL PROTECTED]>, Seigo Tanim
ura writes:
>Those pieces of work were done in the last weekend, and the patch at
>
>Seigo> http://people.FreeBSD.org/~tanimura/patches/vnrecycle.diff
>
>has been updated and now ready to commit.
I'm a bit worried about the amount of work done in the
c
* Seigo Tanimura <[EMAIL PROTECTED]> [010416 03:25] wrote:
> On Fri, 13 Apr 2001 20:08:57 +0900,
> Seigo Tanimura said:
>
> Alfred> Are these changes planned for integration?
>
> Seigo> Yes, but not very soon as there are a few kinds of works that should
> Seigo> be done.
>
> Seigo> One is t
On Fri, 13 Apr 2001 20:08:57 +0900,
Seigo Tanimura said:
Alfred> Are these changes planned for integration?
Seigo> Yes, but not very soon as there are a few kinds of works that should
Seigo> be done.
Seigo> One is that a directory vnode may be held as the working directory of
Seigo> a proces
:Speaking of vmiodirenable, what are the issues with it that it's not
:enabled by default? ISTR that it's been in a while, and most people
:pointed at it have reported success with it, and it seems to have solved
:problems here and there for a number of people. What's keeping it from
:the genera
On Sat, Apr 14, 2001 at 09:34:26AM -0500, Matthew D. Fuller wrote:
> On Thu, Apr 12, 2001 at 02:24:36PM -0700, a little birdie told me
> that Matt Dillon remarked
> >
> > Without vmiodirenable turned on, any directory exceeding
> > vfs.maxmallocbufspace becomes extremely expensive to work
On Thu, Apr 12, 2001 at 02:24:36PM -0700, a little birdie told me
that Matt Dillon remarked
>
> Without vmiodirenable turned on, any directory exceeding
> vfs.maxmallocbufspace becomes extremely expensive to work with
> O(N * diskIO). With vmiodirenable turned on huge directories
>
On Fri, 13 Apr 2001 02:58:07 -0700,
Alfred Perlstein <[EMAIL PROTECTED]> said:
Alfred> * Seigo Tanimura <[EMAIL PROTECTED]> [010413 02:39] wrote:
>> On Thu, 12 Apr 2001 22:50:50 +0200,
>> Poul-Henning Kamp <[EMAIL PROTECTED]> said:
>>
>> Poul-Henning> We keep namecache entries around as long a
* Seigo Tanimura <[EMAIL PROTECTED]> [010413 02:39] wrote:
> On Thu, 12 Apr 2001 22:50:50 +0200,
> Poul-Henning Kamp <[EMAIL PROTECTED]> said:
>
> Poul-Henning> We keep namecache entries around as long as we can use them, and that
> Poul-Henning> generally means that recreating them is a rather
On Thu, 12 Apr 2001 22:50:50 +0200,
Poul-Henning Kamp <[EMAIL PROTECTED]> said:
Poul-Henning> We keep namecache entries around as long as we can use them, and that
Poul-Henning> generally means that recreating them is a rather expensive operation,
Poul-Henning> involving creation of vnode and v
In message <[EMAIL PROTECTED]>, Matt Dillon writes:
>:>:>scaleability.
>:>:
>:>:Uhm, that is actually not true.
>:>:
>:>:We keep namecache entries around as long as we can use them, and that
>:>:generally means that recreating them is a rather expensive operation,
>:>:involving creation of vno
:>:>scaleability.
:>:
:>:Uhm, that is actually not true.
:>:
:>:We keep namecache entries around as long as we can use them, and that
:>:generally means that recreating them is a rather expensive operation,
:>:involving creation of vnode and very likely a vm object again.
:>
:>The vnode ca
In message <[EMAIL PROTECTED]>, Matt Dillon writes:
>
>:
>:In message <[EMAIL PROTECTED]>, Matt Dillon writes:
>:
>:>Again, keep in mind that the namei cache is strictly throw-away, but
>:>entries can often be reconstituted later by the filesystem without I/O
>:>due to the VM Page cach
:
:In message <[EMAIL PROTECTED]>, Matt Dillon writes:
:
:>Again, keep in mind that the namei cache is strictly throw-away, but
:>entries can often be reconstituted later by the filesystem without I/O
:>due to the VM Page cache (and/or buffer cache depending on
:>vfs.vmiodirenable
In message <[EMAIL PROTECTED]>, Matt Dillon writes:
>Again, keep in mind that the namei cache is strictly throw-away, but
>entries can often be reconstituted later by the filesystem without I/O
>due to the VM Page cache (and/or buffer cache depending on
>vfs.vmiodirenable). So as
On Thu, 12 Apr 2001, Matt Dillon wrote:
> Again, keep in mind that the namei cache is strictly throw-away,
This seems to be the main difference between Linux and FreeBSD.
In Linux, open files directly refer to an entry in the dentry
(and inode) cache, so we really need to have dynamically g
:You should also know that negative entries, since they have no
:objects to "hang from" and consequently would clog up the name-cache,
:are limited by the sysctl:
: debug.ncnegfactor: 16
:which means that max 1/16 of the name cache entries can be negative
:entries. You can monitor the numbe
In message <[EMAIL PROTECTED]>, Matt Dillon writes:
>
>:
>:On Tue, 10 Apr 2001, Matt Dillon wrote:
>:
>:>It's randomness that will kill performance. You know the old saying
>:>about caches: They only work if you get cache hits, otherwise
>:>they only slow things down.
>:
>:I wonder .
:
:On Tue, 10 Apr 2001, Matt Dillon wrote:
:
:>It's randomness that will kill performance. You know the old saying
:>about caches: They only work if you get cache hits, otherwise
:>they only slow things down.
:
:I wonder ... how does FreeBSD handle negative directory entries?
:
:Tha
On Tue, 10 Apr 2001, Matt Dillon wrote:
>It's randomness that will kill performance. You know the old saying
>about caches: They only work if you get cache hits, otherwise
>they only slow things down.
I wonder ... how does FreeBSD handle negative directory entries?
That is, /bin/s
Rik van Riel wrote:
>
> I'm curious about the other things though ... FreeBSD still seems
> to have the early 90's abstraction layer from Mach and the vnode
> cache doesn't seem to grow and shrink dynamically (which can be a
> big win for systems with lots of metadata activity).
>
> So while it
It's randomness that will kill performance. You know the old saying
about caches: They only work if you get cache hits, otherwise
they only slow things down.
-Matt
:Which is ok if there isn't too much activity with these data
:structures
On Tue, 10 Apr 2001, Matt Dillon wrote:
> :I'm curious about the other things though ... FreeBSD still seems
> :to have the early 90's abstraction layer from Mach and the vnode
> :cache doesn't seem to grow and shrink dynamically (which can be a
> :big win for systems with lots of metadata activi
:In the balancing part, definately. FreeBSD seems to be the only
:system that has the balancing right. I'm planning on integrating
:some of the balancing tactics into Linux for the 2.5 kernel, but
:I'm not sure how to integrate the inode and dentry cache into the
:balancing scheme ...
:I'm curio
On Tue, 10 Apr 2001, Matt Dillon wrote:
> :I heard NetBSD has implemented a FreeBSD like VM, it also implemented
> :a VM balance in recent verion of NetBSD. some parameters like TEXT,
> :DATA and anonymous memory space can be tuned. is there anyone doing
> :such work on FreeBSD or has FreeBSD alr
>
> FreeBSD implements a very sophisticated VM balancing algorithm. Nobody's
> complaining about it so I don't think we need to really change it. Most
> of the other UNIXes, including Linux, are actually playing catch-up to
> FreeBSD's VM design.
>
I remember hearing/viewing a
:I heard NetBSD has implemented a FreeBSD like VM, it also implemented
:a VM balance in recent verion of NetBSD. some parameters like TEXT,
:DATA and anonymous memory space can be tuned. is there anyone doing
:such work on FreeBSD or has FreeBSD already implemented it?
:
:--
:David Xu
FreeB
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