From: Yicong Yang <yangyicong@huawei.com>
To: <akpm@linux-foundation.org>, <catalin.marinas@arm.com>,
<will@kernel.org>
Cc: wangkefeng.wang@huawei.com, x86@kernel.org,
darren@os.amperecomputing.com, linux-doc@vger.kernel.org,
peterz@infradead.org, yangyicong@hisilicon.com,
punit.agrawal@bytedance.com, guojian@oppo.com,
linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org,
zhangshiming@oppo.com, lipeifeng@oppo.com, corbet@lwn.net,
realmz6@gmail.com, Barry Song <21cnbao@gmail.com>,
linux-mips@vger.kernel.org, arnd@arndb.de,
anshuman.khandual@arm.com, openrisc@lists.librecores.org,
prime.zeng@hisilicon.com, linux-arm-kernel@lists.infradead.org,
linux-mm@kvack.org, xhao@linux.alibaba.com,
linux-kernel@vger.kernel.org, huzhanyuan@oppo.com,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v7 0/2] arm64: support batched/deferred tlb shootdown during page reclamation
Date: Tue, 29 Nov 2022 19:09:28 +0800 [thread overview]
Message-ID: <938c4c00-8cf9-b37a-d70e-04262d86f01c@huawei.com> (raw)
In-Reply-To: <20221117082648.47526-1-yangyicong@huawei.com>
a gentle ping...
Hi Andrew, Will and Catalin,
is it ok to pick this series?
Thanks.
On 2022/11/17 16:26, Yicong Yang wrote:
> From: Yicong Yang <yangyicong@hisilicon.com>
>
> Though ARM64 has the hardware to do tlb shootdown, the hardware
> broadcasting is not free.
> A simplest micro benchmark shows even on snapdragon 888 with only
> 8 cores, the overhead for ptep_clear_flush is huge even for paging
> out one page mapped by only one process:
> 5.36% a.out [kernel.kallsyms] [k] ptep_clear_flush
>
> While pages are mapped by multiple processes or HW has more CPUs,
> the cost should become even higher due to the bad scalability of
> tlb shootdown.
>
> The same benchmark can result in 16.99% CPU consumption on ARM64
> server with around 100 cores according to Yicong's test on patch
> 4/4.
>
> This patchset leverages the existing BATCHED_UNMAP_TLB_FLUSH by
> 1. only send tlbi instructions in the first stage -
> arch_tlbbatch_add_mm()
> 2. wait for the completion of tlbi by dsb while doing tlbbatch
> sync in arch_tlbbatch_flush()
> Testing on snapdragon shows the overhead of ptep_clear_flush
> is removed by the patchset. The micro benchmark becomes 5% faster
> even for one page mapped by single process on snapdragon 888.
>
> With this support we're possible to do more optimization for memory
> reclamation and migration[*].
>
> [*] https://lore.kernel.org/lkml/393d6318-aa38-01ed-6ad8-f9eac89bf0fc@linux.alibaba.com/
>
> -v7:
> 1. rename arch_tlbbatch_add_mm() to arch_tlbbatch_add_pending() as suggested, since it
> takes an extra address for arm64, per Nadav and Anshuman. Also mentioned in the commit.
> 2. add tags from Xin Hao, thanks.
> Link: https://lore.kernel.org/lkml/20221115031425.44640-1-yangyicong@huawei.com/
>
> -v6:
> 1. comment we don't defer TLB flush on platforms affected by ARM64_WORKAROUND_REPEAT_TLBI
> 2. use cpus_have_const_cap() instead of this_cpu_has_cap()
> 3. add tags from Punit, Thanks.
> 4. default enable the feature when cpus >= 8 rather than > 8, since the original
> improvement is observed on snapdragon 888 with 8 cores.
> Link: https://lore.kernel.org/lkml/20221028081255.19157-1-yangyicong@huawei.com/
>
> -v5:
> 1. Make ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH depends on EXPERT for this stage on arm64.
> 2. Make a threshold of CPU numbers for enabling batched TLP flush on arm64
> Link: https://lore.kernel.org/linux-arm-kernel/20220921084302.43631-1-yangyicong@huawei.com/T/
>
> -v4:
> 1. Add tags from Kefeng and Anshuman, Thanks.
> 2. Limit the TLB batch/defer on systems with >4 CPUs, per Anshuman
> 3. Merge previous Patch 1,2-3 into one, per Anshuman
> Link: https://lore.kernel.org/linux-mm/20220822082120.8347-1-yangyicong@huawei.com/
>
> -v3:
> 1. Declare arch's tlbbatch defer support by arch_tlbbatch_should_defer() instead
> of ARCH_HAS_MM_CPUMASK, per Barry and Kefeng
> 2. Add Tested-by from Xin Hao
> Link: https://lore.kernel.org/linux-mm/20220711034615.482895-1-21cnbao@gmail.com/
>
> -v2:
> 1. Collected Yicong's test result on kunpeng920 ARM64 server;
> 2. Removed the redundant vma parameter in arch_tlbbatch_add_mm()
> according to the comments of Peter Zijlstra and Dave Hansen
> 3. Added ARCH_HAS_MM_CPUMASK rather than checking if mm_cpumask
> is empty according to the comments of Nadav Amit
>
> Thanks, Peter, Dave and Nadav for your testing or reviewing
> , and comments.
>
> -v1:
> https://lore.kernel.org/lkml/20220707125242.425242-1-21cnbao@gmail.com/
>
> Anshuman Khandual (1):
> mm/tlbbatch: Introduce arch_tlbbatch_should_defer()
>
> Barry Song (1):
> arm64: support batched/deferred tlb shootdown during page reclamation
>
> .../features/vm/TLB/arch-support.txt | 2 +-
> arch/arm64/Kconfig | 6 +++
> arch/arm64/include/asm/tlbbatch.h | 12 +++++
> arch/arm64/include/asm/tlbflush.h | 52 ++++++++++++++++++-
> arch/x86/include/asm/tlbflush.h | 17 +++++-
> include/linux/mm_types_task.h | 4 +-
> mm/rmap.c | 19 +++----
> 7 files changed, 93 insertions(+), 19 deletions(-)
> create mode 100644 arch/arm64/include/asm/tlbbatch.h
>
prev parent reply other threads:[~2022-11-29 11:10 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-17 8:26 [PATCH v7 0/2] arm64: support batched/deferred tlb shootdown during page reclamation Yicong Yang
2022-11-17 8:26 ` [PATCH v7 1/2] mm/tlbbatch: Introduce arch_tlbbatch_should_defer() Yicong Yang
2022-11-29 23:23 ` Andrew Morton
2022-11-30 2:23 ` Yicong Yang
2022-11-30 2:57 ` Anshuman Khandual
2022-11-17 8:26 ` [PATCH v7 2/2] arm64: support batched/deferred tlb shootdown during page reclamation Yicong Yang
2022-11-23 14:07 ` Anshuman Khandual
2023-01-05 18:14 ` Catalin Marinas
2023-01-08 10:48 ` Barry Song
2023-01-09 17:19 ` Catalin Marinas
2023-01-09 21:28 ` Barry Song
2022-11-29 11:09 ` Yicong Yang [this message]
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=938c4c00-8cf9-b37a-d70e-04262d86f01c@huawei.com \
--to=yangyicong@huawei.com \
--cc=21cnbao@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=anshuman.khandual@arm.com \
--cc=arnd@arndb.de \
--cc=catalin.marinas@arm.com \
--cc=corbet@lwn.net \
--cc=darren@os.amperecomputing.com \
--cc=guojian@oppo.com \
--cc=huzhanyuan@oppo.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mips@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-riscv@lists.infradead.org \
--cc=linux-s390@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=lipeifeng@oppo.com \
--cc=openrisc@lists.librecores.org \
--cc=peterz@infradead.org \
--cc=prime.zeng@hisilicon.com \
--cc=punit.agrawal@bytedance.com \
--cc=realmz6@gmail.com \
--cc=wangkefeng.wang@huawei.com \
--cc=will@kernel.org \
--cc=x86@kernel.org \
--cc=xhao@linux.alibaba.com \
--cc=yangyicong@hisilicon.com \
--cc=zhangshiming@oppo.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).