Re: The 4GB memory thing

Re: The 4GB memory thing

[Andrea Arcangeli]

kanoj@google.engr.sgi.com (Kanoj Sarcar) writes:

> I have a 2.2 patch for 4Gb support, which has seen a lot of stress
> testing by now. The 2.3 >2gb support uses a different (and better
> approach), but last I checked, things like rawio did not work above
> >2Gb. The 64Gb support is completely new ...

2.2.13aa3 includes both 4g bigmem support and rawio and you can do
rawio on all the memory (bigmem included).

	ftp://ftp.*.kernel.org/pub/linux/kernel/people/andrea/kernels/v2.2/2.2.13aa3/

This is the README on how to go in sync with 2.2.13aa3:

	ftp://ftp.*.kernel.org/pub/linux/kernel/people/andrea/tools/apply-patches/README.gz

-- 
Andrea
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Re: The 4GB memory thing

[Kanoj Sarcar]

> 
> kanoj@google.engr.sgi.com (Kanoj Sarcar) writes:
> 
> > I have a 2.2 patch for 4Gb support, which has seen a lot of stress
> > testing by now. The 2.3 >2gb support uses a different (and better
> > approach), but last I checked, things like rawio did not work above
> > >2Gb. The 64Gb support is completely new ...
> 
> 2.2.13aa3 includes both 4g bigmem support and rawio and you can do
> rawio on all the memory (bigmem included).
> 
> 	ftp://ftp.*.kernel.org/pub/linux/kernel/people/andrea/kernels/v2.2/2.2.13aa3/
> 
> This is the README on how to go in sync with 2.2.13aa3:
> 
> 	ftp://ftp.*.kernel.org/pub/linux/kernel/people/andrea/tools/apply-patches/README.gz
> 
> -- 
> Andrea
> 

I don't see a README.gz under 
 http://www.kernel.org/pub/linux/kernel/people/andrea/tools/apply-patches/

In any case, did you a have a small technical README on how rawio works
on bigmem in 2.2.13aa3? Btw, I haven't seen the rawio 2.2 port, I am 
assuming its very similar to 2.3 ... where brw_kiovec() refuses to 
accept PageHighMem pages. I didn't see anything in z-bigmem-2.2.13aa3-7
that tinkers either with fs/buffer.c.

Thanks.

Kanoj
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Re: The 4GB memory thing

[Kanoj Sarcar]

> 
> 
> On Thu, 4 Nov 1999, Kanoj Sarcar wrote:
> 
> > assuming its very similar to 2.3 ... where brw_kiovec() refuses to 
> > accept PageHighMem pages. [...]
> 
> (btw, i have removed this limitation already in my tree, now that
> ll_rw_block() accepts highmem pages as well.)
> 
> -- mingo
> 

Ohh! Are you talking about ll_rw_block() in your tree, or in 2.3.25?
If in 2.3.25, where was the bouncing added?

Kanoj
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Re: The 4GB memory thing

[Ingo Molnar]

On Thu, 4 Nov 1999, Kanoj Sarcar wrote:

> assuming its very similar to 2.3 ... where brw_kiovec() refuses to 
> accept PageHighMem pages. [...]

(btw, i have removed this limitation already in my tree, now that
ll_rw_block() accepts highmem pages as well.)

-- mingo

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Re: The 4GB memory thing

[Andrea Arcangeli]

kanoj@google.engr.sgi.com (Kanoj Sarcar) writes:

> I don't see a README.gz under 
>  http://www.kernel.org/pub/linux/kernel/people/andrea/tools/apply-patches/

lftp> pwd
ftp://ftp.it.kernel.org/pub/linux/kernel/people/andrea/tools/apply-patches
lftp> ls README.gz
-rw-r--r--   1 ftp      daemon        875 Oct 25 00:43 README.gz
lftp> 

> In any case, did you a have a small technical README on how rawio works
> on bigmem in 2.2.13aa3? Btw, I haven't seen the rawio 2.2 port, I am 

As first you can have a look at the rawio patch.

        ftp://ftp.it.kernel.org/pub/linux/kernel/people/andrea/kernels/v2.2/2.2.13aa3/z-bigmem-rawio-2.2.13aa2-1.gz

The above patch includes all the necessary stuff to make rawio working
fine on bigmem pages.

Basically the code uses regular pages as bounce buffers to do the I/O
on bigmem pages.

> assuming its very similar to 2.3 ... where brw_kiovec() refuses to 
> accept PageHighMem pages. I didn't see anything in
> z-bigmem-2.2.13aa3-7

No. The z-bigmem-rawio-2.2.13aa2-1.gz in 2.2.13aa3 allows brw_kiovec
to do I/O on bigmem pages.

> that tinkers either with fs/buffer.c.

I take the bigmem stuff separated from rawio. The rawio patch (pointed
out above) included in 2.2.13aa3 is an incremental patch that goes on the top of
bigmem. I take all the patches separated to allow everybody out there to merge
easily my stuff and to see the only related necessary changes on
topic.

-- 
Andrea
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Re: The 4GB memory thing

[Ingo Molnar]

On Thu, 4 Nov 1999, Kanoj Sarcar wrote:

> > > assuming its very similar to 2.3 ... where brw_kiovec() refuses to 
> > > accept PageHighMem pages. [...]
> > 
> > (btw, i have removed this limitation already in my tree, now that
> > ll_rw_block() accepts highmem pages as well.)
> 
> Ohh! Are you talking about ll_rw_block() in your tree, or in 2.3.25?
> If in 2.3.25, where was the bouncing added?

my tree.

	Ingo

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Re: The 4GB memory thing

[Kanoj Sarcar]

> 
> This is a multi-part message in MIME format.
> --------------8C597550CEC840E9F68E4220
> Content-Type: text/plain; charset=us-ascii
> Content-Transfer-Encoding: 7bit
> 
> The recent thread about >4GB surprised me, as I didn't even think >2GB
> was very stable yet.  Am I wrong?  Are people out there using 4GB boxes
> with decent stability?  I presume it's a 2.3 feature, yes?
> 
> Sorry for my ignorance, I guess I've been dozing a bit of late.
> 
> Neil

I have a 2.2 patch for 4Gb support, which has seen a lot of stress
testing by now. The 2.3 >2gb support uses a different (and better
approach), but last I checked, things like rawio did not work above
>2Gb. The 64Gb support is completely new ...

Kanoj
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The 4GB memory thing

[Neil Conway]

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The recent thread about >4GB surprised me, as I didn't even think >2GB
was very stable yet.  Am I wrong?  Are people out there using 4GB boxes
with decent stability?  I presume it's a 2.3 feature, yes?

Sorry for my ignorance, I guess I've been dozing a bit of late.

Neil

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From: Neil Conway <nconway.list@ukaea.org.uk>
To: "linux-smp@vger.rutgers.edu" <linux-smp@vger.rutgers.edu>
Subject: The 4GB memory thing
Date: Wed, 03 Nov 1999 09:46:14 +0000
Message-ID: <38200466.5839E78E@ukaea.org.uk>

The recent thread about >4GB surprised me, as I didn't even think >2GB
was very stable yet.  Am I wrong?  Are people out there using 4GB boxes
with decent stability?  I presume it's a 2.3 feature, yes?

Sorry for my ignorance, I guess I've been dozing a bit of late.

Neil