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Subject: Re: [PATCH v8 0/6] optimize memblock_next_valid_pfn and
 early_pfn_valid on arm and arm64
To:     Daniel Vacek <neelx@redhat.com>, Jia He <hejianet@gmail.com>
Cc:     Russell King <linux@armlinux.org.uk>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Michal Hocko <mhocko@suse.com>,
        Wei Yang <richard.weiyang@gmail.com>,
        Kees Cook <keescook@chromium.org>,
        Laura Abbott <labbott@redhat.com>,
        Vladimir Murzin <vladimir.murzin@arm.com>,
        Philip Derrin <philip@cog.systems>,
        AKASHI Takahiro <takahiro.akashi@linaro.org>,
        James Morse <james.morse@arm.com>,
        Steve Capper <steve.capper@arm.com>,
        Gioh Kim <gi-oh.kim@profitbricks.com>,
        Vlastimil Babka <vbabka@suse.cz>, Mel Gorman <mgorman@suse.de>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Kemi Wang <kemi.wang@intel.com>,
        Petr Tesarik <ptesarik@suse.com>,
        YASUAKI ISHIMATSU <yasu.isimatu@gmail.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Nikolay Borisov <nborisov@suse.com>,
        Daniel Jordan <daniel.m.jordan@oracle.com>,
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        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        open list <linux-kernel@vger.kernel.org>,
        Linux-MM <linux-mm@kvack.org>
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From:   Pavel Tatashin <pasha.tatashin@oracle.com>
Message-ID: <23b14717-0f4a-10f2-5118-7cb8445fbdab@oracle.com>
Date:   Fri, 4 May 2018 12:53:40 -0400
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> 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.

Thank you,
Pavel