linux-kernel - Re: [PATCH v6 0/2] use static key to optimize pgtable_l4_enabled

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Message-ID: <YvhVktaSeK0vLmhB@xhacker>
Date:   Sun, 14 Aug 2022 09:53:22 +0800
From:   Jisheng Zhang <jszhang@...nel.org>
To:     Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Andrey Ryabinin <ryabinin.a.a@...il.com>,
        Alexander Potapenko <glider@...gle.com>,
        Andrey Konovalov <andreyknvl@...il.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Vincenzo Frascino <vincenzo.frascino@....com>,
        Alexandre Ghiti <alexandre.ghiti@...onical.com>,
        Emil Renner Berthing <emil.renner.berthing@...onical.com>
Cc:     linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        kasan-dev@...glegroups.com
Subject: Re: [PATCH v6 0/2] use static key to optimize pgtable_l4_enabled

On Sat, Jul 16, 2022 at 07:50:57PM +0800, Jisheng Zhang wrote:
> The pgtable_l4|[l5]_enabled check sits at hot code path, performance
> is impacted a lot. Since pgtable_l4|[l5]_enabled isn't changed after
> boot, so static key can be used to solve the performance issue[1].
> 
> An unified way static key was introduced in [2], but it only targets
> riscv isa extension. We dunno whether SV48 and SV57 will be considered
> as isa extension, so the unified solution isn't used for
> pgtable_l4[l5]_enabled now.
> 
> patch1 fixes a NULL pointer deference if static key is used a bit earlier.
> patch2 uses the static key to optimize pgtable_l4|[l5]_enabled.
> 
> [1] http://lists.infradead.org/pipermail/linux-riscv/2021-December/011164.html
> [2] https://lore.kernel.org/linux-riscv/20220517184453.3558-1-jszhang@kernel.org/T/#t

Hi Palmer,

I see part1 and part2 were sent out...
What I can do to make this series merged for 6.0-rc1? I'm afraid this series
may miss anothe round of merge window again.

Thanks in advance

> 
> Since v5:
>  - Use DECLARE_STATIC_KEY_FALSE
> 
> Since v4:
>  - rebased on v5.19-rcN
>  - collect Reviewed-by tags
>  - Fix kernel panic issue if SPARSEMEM is enabled by moving the
>    riscv_finalise_pgtable_lx() after sparse_init()
> 
> Since v3:
>  - fix W=1 call to undeclared function 'static_branch_likely' error
> 
> Since v2:
>  - move the W=1 warning fix to a separate patch
>  - move the unified way to use static key to a new patch series.
> 
> Since v1:
>  - Add a W=1 warning fix
>  - Fix W=1 error
>  - Based on v5.18-rcN, since SV57 support is added, so convert
>    pgtable_l5_enabled as well.
> 
> Jisheng Zhang (2):
>   riscv: move sbi_init() earlier before jump_label_init()
>   riscv: turn pgtable_l4|[l5]_enabled to static key for RV64
> 
>  arch/riscv/include/asm/pgalloc.h    | 16 ++++----
>  arch/riscv/include/asm/pgtable-32.h |  3 ++
>  arch/riscv/include/asm/pgtable-64.h | 60 ++++++++++++++++++---------
>  arch/riscv/include/asm/pgtable.h    |  5 +--
>  arch/riscv/kernel/cpu.c             |  4 +-
>  arch/riscv/kernel/setup.c           |  2 +-
>  arch/riscv/mm/init.c                | 64 ++++++++++++++++++-----------
>  arch/riscv/mm/kasan_init.c          | 16 ++++----
>  8 files changed, 104 insertions(+), 66 deletions(-)
> 
> -- 
> 2.34.1
> 
> 
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv

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