From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3244CC43334 for ; Fri, 15 Jul 2022 13:44:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233866AbiGONos (ORCPT ); Fri, 15 Jul 2022 09:44:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47612 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229648AbiGONop (ORCPT ); Fri, 15 Jul 2022 09:44:45 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9A95147BAE for ; Fri, 15 Jul 2022 06:44:43 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 2C8EF623D5 for ; Fri, 15 Jul 2022 13:44:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CA350C34115; Fri, 15 Jul 2022 13:44:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1657892682; bh=8BPiocY7scDyLEcAlQjPC++udc/2v52MfXgPwsWJmaM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=U/7omktuc5K9bv7/vVtx7s2hZGuEbq0x4Dh4gwEpveYMluuJqTFobMI6tTQq11MLB gIQ9PaLyEE9Muo+wlE9HzsHn1dKUYJC7GRQWYiJQ52ZMnxahn1VyzKEraFZtTIW/h6 1FuC6wRdT1JG5zL75xUh52YjQ27H+tseApcbggAtffCJre2UsHzQJVRw7N3Ivn0kqK yBF60fvKOtN94xRY7MzDB95QGSINMLmbfbknA1Z4mEjxXOkqiWApUvyyyNd0/K06uX 6FgysEEhgFN/3+LHriZH+Kloq/Td8aj4sdmOX18TkCAxSkScaj6bIcdEuxzoQ6DJiw U1ooy1Ii1DwUQ== Date: Fri, 15 Jul 2022 21:35:43 +0800 From: Jisheng Zhang To: Palmer Dabbelt Cc: anup@brainfault.org, Paul Walmsley , aou@eecs.berkeley.edu, ryabinin.a.a@gmail.com, glider@google.com, andreyknvl@gmail.com, dvyukov@google.com, vincenzo.frascino@arm.com, alexandre.ghiti@canonical.com, Atish Patra , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com Subject: Re: [PATCH v4 0/2] use static key to optimize pgtable_l4_enabled Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 01, 2022 at 08:48:25PM -0700, Palmer Dabbelt wrote: > On Sat, 25 Jun 2022 21:33:07 PDT (-0700), anup@brainfault.org wrote: > > On Sat, May 21, 2022 at 8:13 PM 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 > > > > > > 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 > > > > I have tested both these patches on QEMU RV64 and RV32. > > > > Tested-by: Anup Patel > > > > Thanks, > > Anup > > Thanks for testing these. Unfortunatly they're failing for me under my > kasan+sparsemem-vmemmap config, which looks like a defconfig with > > CONFIG_KASAN=y > # CONFIG_FLATMEM_MANUAL is not set > CONFIG_SPARSEMEM_MANUAL=y > CONFIG_SPARSEMEM=y > # CONFIG_SPARSEMEM_VMEMMAP is not set Hi Palmer, Thank you for the hint, I find the reason: SPARSEMEM is the key, KASAN doesn't matter. To fix this issue, we need to move riscv_finalise_pgtable_lx() after sparse_init(). I will send out a newer version soon. > > Nothing's really jumping out and I'm not sure that's a super compelling > configuration, but IIRC it's found a handful of issues before so I'm not > sure it's sane to just toss it. > > I've put this all on the riscv-pgtable_static_key branch of > kernel.org/palmer/linux . If nobody has the time to look then I'll try and > give it another shot, but I'm pretty buried right now so happy to have the > help. Let me know if you want a seperate patch against riscv-pgtable_static_key branch. Thanks > > > > > > > > > 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 > > >