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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Wed, 16 Nov 2022 09:45:04 -0800
Message-ID: <CAHk-=win6sosEYKi1HcmEFDVH8S4cWntb1RH1z_=Tbkk45ZTLA@mail.gmail.com>
Subject: Re: mm: mmu_gather: do not expose delayed_rmap flag
To:     Alexander Gordeev <agordeev@linux.ibm.com>
Cc:     Hugh Dickins <hughd@google.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Nadav Amit <nadav.amit@gmail.com>,
        Will Deacon <will@kernel.org>,
        Aneesh Kumar <aneesh.kumar@linux.ibm.com>,
        Nick Piggin <npiggin@gmail.com>,
        Heiko Carstens <hca@linux.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Christian Borntraeger <borntraeger@linux.ibm.com>,
        Sven Schnelle <svens@linux.ibm.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Gerald Schaefer <gerald.schaefer@linux.ibm.com>
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On Tue, Nov 15, 2022 at 11:49 PM Alexander Gordeev
<agordeev@linux.ibm.com> wrote:
>
> Flag delayed_rmap of 'struct mmu_gather' is rather
> a private member, but it is still accessed directly.
> Instead, let the TLB gather code access the flag.

Now, I set it up so that if you don't use delayed_rmap, the
tlb_flush_rmaps() function ends up being an empty inline function, and
as such the compiler should already have done this for you - including
optimizing out the test that then doesn't even matter.

But this patch shouldn't *matter*, but it also isn't wrong, so..

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>

Thanks,

                    Linus