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From:   Shakeel Butt <shakeelb@google.com>
Date:   Sat, 12 Jan 2019 08:50:42 -0800
Message-ID: <CALvZod5XfFujzzMC0n2dZmofjof0juWw45RF4475CAEu9nAv3Q@mail.gmail.com>
Subject: Re: [PATCH] mm: Introduce GFP_PGTABLE
To:     Matthew Wilcox <willy@infradead.org>
Cc:     Christophe Leroy <christophe.leroy@c-s.fr>,
        Anshuman Khandual <anshuman.khandual@arm.com>,
        mark.rutland@arm.com, Michal Hocko <mhocko@suse.com>,
        linux-sh@vger.kernel.org, peterz@infradead.org,
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        linux@armlinux.org.uk, Ingo Molnar <mingo@redhat.com>,
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On Sat, Jan 12, 2019 at 7:50 AM Matthew Wilcox <willy@infradead.org> wrote:
>
> On Sat, Jan 12, 2019 at 02:49:29PM +0100, Christophe Leroy wrote:
> > As far as I can see,
> >
> > #define GFP_KERNEL_ACCOUNT (GFP_KERNEL | __GFP_ACCOUNT)
> >
> > So what's the difference between:
> >
> > (GFP_KERNEL_ACCOUNT | __GFP_ZERO) & ~__GFP_ACCOUNT
> >
> > and
> >
> > (GFP_KERNEL | __GFP_ZERO) & ~__GFP_ACCOUNT
>
> Nothing.  But there's a huge difference in the other parts of that same
> file where GFP_ACCOUNT is _not_ used.
>
> I think this unification is too small to bother with.  Something I've
> had on my todo list for some time and have not done anything about
> is to actually unify all of the architecture pte/pmd/... allocations.
> There are tricks some architectures use that others would benefit from.

Can you explain a bit more on this? If this is too low priority on
your todo list then maybe me or someone else can pick that up.

Shakeel