linux-kernel - [PATCH 0/1] mm: Optimizing hugepage zeroing in arm64

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Date:   Thu, 21 Jan 2021 22:21:50 +0530
From:   Prathu Baronia <prathubaronia2011@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     chintan.pandya@...plus.com,
        Prathu Baronia <prathu.baronia@...plus.com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Vincenzo Frascino <vincenzo.frascino@....com>,
        "glider@...gle.com" <glider@...gle.com>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Anshuman Khandual <anshuman.khandual@....com>,
        Andrey Konovalov <andreyknvl@...gle.com>,
        linux-arm-kernel@...ts.infradead.org
Subject: [PATCH 0/1] mm: Optimizing hugepage zeroing in arm64

Hello!

This patch removes the unnecessary kmap calls in the hugepage zeroing path and
improves the timing by 62%.

I had proposed a similar change in Apr-May'20 timeframe in memory.c where I
proposed to clear out a hugepage by directly calling a memset over the whole
hugepage but got the opposition that the change was not architecturally neutral.

Upon revisiting this now I see significant improvement by removing around 2k
barrier calls from the zeroing path. So hereby I propose an arm64 specific
definition of clear_user_highpage().

Prathu Baronia (1):
  mm: Optimizing hugepage zeroing in arm64

 arch/arm64/include/asm/page.h | 3 +++
 arch/arm64/mm/copypage.c      | 8 ++++++++
 2 files changed, 11 insertions(+)

-- 
2.17.1