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From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Linux MM <linux-mm@kvack.org>, Guo Ren <guoren@kernel.org>,
	Ralf Baechle <ralf@linux-mips.org>,
	Paul Burton <paulburton@kernel.org>,
	Mike Rapoport <rppt@linux.ibm.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-m68k <linux-m68k@lists.linux-m68k.org>,
	linux-mips@vger.kernel.org, linux-csky@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm/vma: Append unlikely() while testing VMA access permissions
Date: Mon, 24 Feb 2020 11:09:52 +0100	[thread overview]
Message-ID: <CAMuHMdXMSTLevTH1gkM8B53LtRUQ80o=t+W27z0QT-dNKkkYgQ@mail.gmail.com> (raw)
In-Reply-To: <1582525304-32113-1-git-send-email-anshuman.khandual@arm.com>

Hi Anshuman,

Thanks for your patch!

On Mon, Feb 24, 2020 at 7:22 AM Anshuman Khandual
<anshuman.khandual@arm.com> wrote:
> It is unlikely that an inaccessible VMA without required permission flags
> will get a page fault. Hence lets just append unlikely() directive to such

Why? Isn't it the idea that you get a page fault when the page is not
accessible?

> checks in order to improve performance while also standardizing it across
> various platforms.

Does it make a difference to add these? Have you benchmarked this?
https://lwn.net/Articles/420019/

Gr{oetje,eeting}s,

                        Geert


--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

  reply	other threads:[~2020-02-24 10:10 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-24  6:21 [PATCH] mm/vma: Append unlikely() while testing VMA access permissions Anshuman Khandual
2020-02-24 10:09 ` Geert Uytterhoeven [this message]
2020-02-24 13:19   ` Anshuman Khandual

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