From: "Björn Töpel" <bjorn@kernel.org>
To: David Hildenbrand <david@redhat.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
linux-riscv@lists.infradead.org,
Anshuman Khandual <anshuman.khandual@arm.com>
Cc: "Björn Töpel" <bjorn@rivosinc.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
"Oscar Salvador" <osalvador@suse.de>,
virtualization@lists.linux-foundation.org, linux@rivosinc.com,
"Alexandre Ghiti" <alexghiti@rivosinc.com>
Subject: Re: [PATCH 0/7] riscv: Memory Hot(Un)Plug support
Date: Sun, 21 May 2023 11:15:29 +0200 [thread overview]
Message-ID: <87lehikpu6.fsf@all.your.base.are.belong.to.us> (raw)
In-Reply-To: <87zg62eqm4.fsf@all.your.base.are.belong.to.us>
Hi David and Anshuman!
Björn Töpel <bjorn@kernel.org> writes:
> David Hildenbrand <david@redhat.com> writes:
>
>> On 12.05.23 16:57, Björn Töpel wrote:
>>> From: Björn Töpel <bjorn@rivosinc.com>
>>>
>>> Memory Hot(Un)Plug support for the RISC-V port
>>> ==============================================
>
> [...]
>
>>
>> Cool stuff! I'm fairly busy right now, so some high-level questions upfront:
>
> No worries, and no rush! I'd say the v1 series was mainly for the RISC-V
> folks, and I've got tons of (offline) comments from Alex -- and with
> your comments below some more details to figure out.
One of the major issues with my v1 patch is around init_mm page table
synchronization, and that'll be part of the v2.
I've noticed there's a quite a difference between x86-64 and arm64 in
terms of locking, when updating (add/remove) the init_mm table. x86-64
uses the usual page table locking mechanisms (used by the generic
kernel functions), whereas arm64 does not.
How does arm64 manage to mix the "lock-less" updates (READ/WRITE_ONCE,
and fences in set_p?d+friends), with the generic kernel ones that uses
the regular page locking mechanism?
I'm obviously missing something about the locking rules for memory hot
add/remove... I've been reading the arm64 memory hot add/remove
series, but none the wiser! ;-)
Björn
next prev parent reply other threads:[~2023-05-21 9:15 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-12 14:57 Björn Töpel
2023-05-12 14:57 ` [PATCH 1/7] riscv: mm: Pre-allocate PGD leaves to avoid synchronization Björn Töpel
2023-05-12 14:57 ` [PATCH 2/7] riscv: mm: Change attribute from __init to __meminit for page functions Björn Töpel
2023-05-12 14:57 ` [PATCH 3/7] riscv: mm: Refactor create_linear_mapping_range() for hot add Björn Töpel
2023-06-21 23:56 ` Palmer Dabbelt
2023-06-22 4:56 ` Björn Töpel
2023-05-12 14:57 ` [PATCH 4/7] riscv: mm: Add memory hot add/remove support Björn Töpel
2023-05-12 14:57 ` [PATCH 5/7] riscv: Enable memory hot add/remove arch kbuild support Björn Töpel
2023-05-12 14:57 ` [PATCH 6/7] virtio-mem: Enable virtio-mem for RISC-V Björn Töpel
2023-05-12 14:57 ` [PATCH 7/7] riscv: mm: Pre-allocate vmalloc PGD leaves Björn Töpel
2023-05-17 13:49 ` [PATCH 0/7] riscv: Memory Hot(Un)Plug support David Hildenbrand
2023-05-17 18:53 ` Björn Töpel
2023-05-21 9:15 ` Björn Töpel [this message]
2023-05-22 8:21 ` David Hildenbrand
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