From: Pavel Tatashin <pasha.tatashin@soleen.com>
To: Pavel Tatashin <pasha.tatashin@soleen.com>,
James Morris <jmorris@namei.org>,
Sasha Levin <sashal@kernel.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
kexec mailing list <kexec@lists.infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
Jonathan Corbet <corbet@lwn.net>,
Catalin Marinas <catalin.marinas@arm.com>,
will@kernel.org, Linux ARM <linux-arm-kernel@lists.infradead.org>,
Marc Zyngier <marc.zyngier@arm.com>,
James Morse <james.morse@arm.com>,
Vladimir Murzin <vladimir.murzin@arm.com>,
Matthias Brugger <matthias.bgg@gmail.com>,
Bhupesh Sharma <bhsharma@redhat.com>,
linux-mm <linux-mm@kvack.org>
Subject: Re: [PATCH v1 0/8] arm64: MMU enabled kexec relocation
Date: Thu, 15 Aug 2019 13:16:20 -0400 [thread overview]
Message-ID: <CA+CK2bD6e2WGxuPG+jX8c_qyHNZOC=8NZ-wVZXQuMS2ncBNndg@mail.gmail.com> (raw)
In-Reply-To: <CA+CK2bADiBMEx9cJuXT5fQkBYFZAtxUtc7ZzjrNfEjijPZkPtw@mail.gmail.com>
Hi,
It is been two weeks, and no review activity yet. Please help with
reviewing this work.
Thank you,
Pasha
On Thu, Aug 8, 2019 at 2:44 PM Pavel Tatashin <pasha.tatashin@soleen.com> wrote:
>
> Just a friendly reminder, please send your comments on this series.
> It's been a week since I sent out these patches, and no feedback yet.
> Also, I'd appreciate if anyone could test this series on vhe hardware
> with vhe kernel, it does not look like QEMU can emulate it yet
>
> Thank you,
> Pasha
>
> On Thu, Aug 1, 2019 at 11:24 AM Pavel Tatashin
> <pasha.tatashin@soleen.com> wrote:
> >
> > Enable MMU during kexec relocation in order to improve reboot performance.
> >
> > If kexec functionality is used for a fast system update, with a minimal
> > downtime, the relocation of kernel + initramfs takes a significant portion
> > of reboot.
> >
> > The reason for slow relocation is because it is done without MMU, and thus
> > not benefiting from D-Cache.
> >
> > Performance data
> > ----------------
> > For this experiment, the size of kernel plus initramfs is small, only 25M.
> > If initramfs was larger, than the improvements would be greater, as time
> > spent in relocation is proportional to the size of relocation.
> >
> > Previously:
> > kernel shutdown 0.022131328s
> > relocation 0.440510736s
> > kernel startup 0.294706768s
> >
> > Relocation was taking: 58.2% of reboot time
> >
> > Now:
> > kernel shutdown 0.032066576s
> > relocation 0.022158152s
> > kernel startup 0.296055880s
> >
> > Now: Relocation takes 6.3% of reboot time
> >
> > Total reboot is x2.16 times faster.
> >
> > Previous approaches and discussions
> > -----------------------------------
> > https://lore.kernel.org/lkml/20190709182014.16052-1-pasha.tatashin@soleen.com
> > reserve space for kexec to avoid relocation, involves changes to generic code
> > to optimize a problem that exists on arm64 only:
> >
> > https://lore.kernel.org/lkml/20190716165641.6990-1-pasha.tatashin@soleen.com
> > The first attempt to enable MMU, some bugs that prevented performance
> > improvement. The page tables unnecessary configured idmap for the whole
> > physical space.
> >
> > https://lore.kernel.org/lkml/20190731153857.4045-1-pasha.tatashin@soleen.com
> > No linear copy, bug with EL2 reboots.
> >
> > Pavel Tatashin (8):
> > kexec: quiet down kexec reboot
> > arm64, mm: transitional tables
> > arm64: hibernate: switch to transtional page tables.
> > kexec: add machine_kexec_post_load()
> > arm64, kexec: move relocation function setup and clean up
> > arm64, kexec: add expandable argument to relocation function
> > arm64, kexec: configure transitional page table for kexec
> > arm64, kexec: enable MMU during kexec relocation
> >
> > arch/arm64/Kconfig | 4 +
> > arch/arm64/include/asm/kexec.h | 51 ++++-
> > arch/arm64/include/asm/pgtable-hwdef.h | 1 +
> > arch/arm64/include/asm/trans_table.h | 68 ++++++
> > arch/arm64/kernel/asm-offsets.c | 14 ++
> > arch/arm64/kernel/cpu-reset.S | 4 +-
> > arch/arm64/kernel/cpu-reset.h | 8 +-
> > arch/arm64/kernel/hibernate.c | 261 ++++++-----------------
> > arch/arm64/kernel/machine_kexec.c | 199 ++++++++++++++----
> > arch/arm64/kernel/relocate_kernel.S | 196 +++++++++---------
> > arch/arm64/mm/Makefile | 1 +
> > arch/arm64/mm/trans_table.c | 273 +++++++++++++++++++++++++
> > kernel/kexec.c | 4 +
> > kernel/kexec_core.c | 8 +-
> > kernel/kexec_file.c | 4 +
> > kernel/kexec_internal.h | 2 +
> > 16 files changed, 758 insertions(+), 340 deletions(-)
> > create mode 100644 arch/arm64/include/asm/trans_table.h
> > create mode 100644 arch/arm64/mm/trans_table.c
> >
> > --
> > 2.22.0
> >
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next prev parent reply other threads:[~2019-08-15 17:16 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-01 15:24 [PATCH v1 0/8] arm64: MMU enabled kexec relocation Pavel Tatashin
2019-08-01 15:24 ` [PATCH v1 1/8] kexec: quiet down kexec reboot Pavel Tatashin
2019-08-01 15:24 ` [PATCH v1 2/8] arm64, mm: transitional tables Pavel Tatashin
2019-08-15 18:11 ` James Morse
2019-08-15 20:18 ` Pavel Tatashin
2019-08-01 15:24 ` [PATCH v1 3/8] arm64: hibernate: switch to transtional page tables Pavel Tatashin
2019-08-01 15:24 ` [PATCH v1 4/8] kexec: add machine_kexec_post_load() Pavel Tatashin
2019-08-01 15:24 ` [PATCH v1 5/8] arm64, kexec: move relocation function setup and clean up Pavel Tatashin
2019-08-01 15:24 ` [PATCH v1 6/8] arm64, kexec: add expandable argument to relocation function Pavel Tatashin
2019-08-01 15:24 ` [PATCH v1 7/8] arm64, kexec: configure transitional page table for kexec Pavel Tatashin
2019-08-01 15:24 ` [PATCH v1 8/8] arm64, kexec: enable MMU during kexec relocation Pavel Tatashin
2019-08-08 18:44 ` [PATCH v1 0/8] arm64: MMU enabled " Pavel Tatashin
2019-08-15 17:16 ` Pavel Tatashin [this message]
2019-08-15 18:11 ` James Morse
2019-08-15 20:09 ` Pavel Tatashin
2019-08-16 18:17 ` James Morse
2019-08-16 19:19 ` Pavel Tatashin
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