From: Jisheng Zhang <jszhang@kernel.org>
To: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
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,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
kasan-dev@googlegroups.com
Subject: Re: [PATCH v6 RESEND 0/2] use static key to optimize pgtable_l4_enabled
Date: Thu, 6 Oct 2022 16:37:52 +0800 [thread overview]
Message-ID: <Yz6T4EYKKns7OIVE@xhacker> (raw)
In-Reply-To: <mhng-30c89107-c103-4363-b4af-7778d9512622@palmer-ri-x1c9>
On Wed, Oct 05, 2022 at 06:05:28PM -0700, Palmer Dabbelt wrote:
> On Sun, 21 Aug 2022 07:09:16 PDT (-0700), jszhang@kernel.org 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 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(-)
>
> Sorry for being slow here, but it looks like this still causes some early
> boot hangs. Specifically kasan+sparsemem is failing. As you can probably
> see from the latency I'm still a bit buried right now so I'm not sure when
> I'll have a chance to take more of a look.
Hi Palmer,
Before V4, there is a bug which can cause kernel panic when SPARSEMEM
is enabled, V4 have fixed it by moving the riscv_finalise_pgtable_lx()
after sparse_init(). And I just tested the riscv-pgtable_static_key
branch in your tree, enabling KASAN and SPARSEMEM, system booted fine.
I'm not sure what happened. Could you please send me your kernel
config file? I want to fix any issue which can block this series being
merged in 6.1-rc1.
Thanks in advance
next prev parent reply other threads:[~2022-10-06 8:47 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-21 14:09 [PATCH v6 RESEND 0/2] use static key to optimize pgtable_l4_enabled Jisheng Zhang
2022-08-21 14:09 ` [PATCH v6 RESEND 1/2] riscv: move sbi_init() earlier before jump_label_init() Jisheng Zhang
2022-08-21 14:09 ` [PATCH v6 RESEND 2/2] riscv: turn pgtable_l4|[l5]_enabled to static key for RV64 Jisheng Zhang
2022-10-06 1:05 ` [PATCH v6 RESEND 0/2] use static key to optimize pgtable_l4_enabled Palmer Dabbelt
2022-10-06 8:37 ` Jisheng Zhang [this message]
2022-10-08 14:28 ` Jisheng Zhang
2022-12-11 10:43 ` Jisheng Zhang
2023-01-11 17:28 ` Jisheng Zhang
2023-01-11 19:00 ` Andrew Jones
2023-01-11 20:51 ` Jessica Clarke
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=Yz6T4EYKKns7OIVE@xhacker \
--to=jszhang@kernel.org \
--cc=alexandre.ghiti@canonical.com \
--cc=andreyknvl@gmail.com \
--cc=aou@eecs.berkeley.edu \
--cc=dvyukov@google.com \
--cc=glider@google.com \
--cc=kasan-dev@googlegroups.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-riscv@lists.infradead.org \
--cc=palmer@dabbelt.com \
--cc=paul.walmsley@sifive.com \
--cc=ryabinin.a.a@gmail.com \
--cc=vincenzo.frascino@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).