About the status of hugepage filtering!

About the status of hugepage filtering!

[Baoquan He]

Hi Astushi,

I remember earlier Jingbai posted a patchset on hugepage filtering,
later you pasted your hugepage filtering prototype patch, and people
thought yours is better. So now may I know the status and what's your
plan?

Because in makedumpfile 1.5.6, this is not delivered. Your plan can help
us much.

Thanks
Baoquan


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Re: About the status of hugepage filtering!

[Petr Tesarik]

On Mon, 28 Apr 2014 15:56:05 +0800
Baoquan He <bhe@redhat.com> wrote:

> Hi Astushi,
> 
> I remember earlier Jingbai posted a patchset on hugepage filtering,
> later you pasted your hugepage filtering prototype patch, and people
> thought yours is better. So now may I know the status and what's your
> plan?
> 
> Because in makedumpfile 1.5.6, this is not delivered. Your plan can help
> us much.

Hi Baoquan,

I followed up on Atsushi's prototype, and there's a patch series
sitting on my disk which just came too late for 1.5.6, so I held it
back. It was also suggested that the mdf_pfn cleanup patch be applied
first. That one is now in, and I'll send an updated series shortly.

The first part of the change is the "Generic handling of multi-page
exclusions", that is a method which can be used for excluding both free
pages and compound pages (and without adding even more complexity to
the calculation of the cycle size).

The second part is handling of hugepages. This simply extends the
algorithm so that all pages in a compound page are treated as one
object. To make it work, additional info must be exported from the
kernel. This is where I got stuck with my previous attempt. For now,
this patch is already in the mm tree:

http://ozlabs.org/~akpm/mmotm/broken-out/kexec-save-pg_head_mask-in-vmcoreinfo.patch

Petr T

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Re: About the status of hugepage filtering!

[Baoquan He]

On 04/28/14 at 12:21pm, Petr Tesarik wrote:
> On Mon, 28 Apr 2014 15:56:05 +0800
> Baoquan He <bhe@redhat.com> wrote:
> 
> > Hi Astushi,
> > 
> > I remember earlier Jingbai posted a patchset on hugepage filtering,
> > later you pasted your hugepage filtering prototype patch, and people
> > thought yours is better. So now may I know the status and what's your
> > plan?
> > 
> > Because in makedumpfile 1.5.6, this is not delivered. Your plan can help
> > us much.
> 
> Hi Baoquan,
> 
> I followed up on Atsushi's prototype, and there's a patch series
> sitting on my disk which just came too late for 1.5.6, so I held it
> back. It was also suggested that the mdf_pfn cleanup patch be applied
> first. That one is now in, and I'll send an updated series shortly.
> 
> The first part of the change is the "Generic handling of multi-page
> exclusions", that is a method which can be used for excluding both free
> pages and compound pages (and without adding even more complexity to
> the calculation of the cycle size).
> 
> The second part is handling of hugepages. This simply extends the
> algorithm so that all pages in a compound page are treated as one
> object. To make it work, additional info must be exported from the
> kernel. This is where I got stuck with my previous attempt. For now,
> this patch is already in the mm tree:
> 
> http://ozlabs.org/~akpm/mmotm/broken-out/kexec-save-pg_head_mask-in-vmcoreinfo.patch

Hi Petr,

Good to know this progress. And it's awesome that kernel patch exporting
PG_head_mask has been in mm tree.

I saw people had discussed heatedly about the generic handling of
multi-page exclusions. So as long as the first part passes through and
merged in, hugepage filtering adding will be supported very smoothly, is
that right? I didn't follow up that thread very closely, if yes, it's a
great news. And thanks for your effort.

Thanks
Baoquan

> 
> Petr T

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