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From:   Daniel Vacek <neelx@redhat.com>
Date:   Fri, 4 May 2018 20:33:56 +0200
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Subject: Re: [PATCH v8 0/6] optimize memblock_next_valid_pfn and
 early_pfn_valid on arm and arm64
To:     Pavel Tatashin <pasha.tatashin@oracle.com>
Cc:     Jia He <hejianet@gmail.com>, Russell King <linux@armlinux.org.uk>,
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On Fri, May 4, 2018 at 6:53 PM, Pavel Tatashin
<pasha.tatashin@oracle.com> wrote:
>> I'm wondering, ain't simple enabling of config
>> DEFERRED_STRUCT_PAGE_INIT provide even better speed-up? If that is the
>> case then it seems like this series is not needed at all, right?
>> I am not sure why is this config optional. It looks like it could be
>> enabled by default or even unconditionally considering that with
>> commit c9e97a1997fb ("mm: initialize pages on demand during boot") the
>> deferred code is statically disabled after all the pages are
>> initialized.
>
> Hi Daniel,
>
> Currently, deferred struct pages are initialized in parallel only on NUMA machines. I would like to make a change to use all the available CPUs even on a single socket systems, but that is not there yet. So, I believe Jia's performance improvements are still relevant.

Ahaa, I thought it also works on UP or single node systems. I didn't
study the code closely. Sorry about the noise. And thank you, Pavel.
You're right.

--nX

> Thank you,
> Pavel