From: Oliver Upton <oliver.upton@linux.dev>
To: Yu Zhao <yuzhao@google.com>
Cc: James Houghton <jthoughton@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Paolo Bonzini <pbonzini@redhat.com>,
David Matlack <dmatlack@google.com>,
Marc Zyngier <maz@kernel.org>,
Sean Christopherson <seanjc@google.com>,
Jonathan Corbet <corbet@lwn.net>,
James Morse <james.morse@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Zenghui Yu <yuzenghui@huawei.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Shaoqin Huang <shahuang@redhat.com>,
Gavin Shan <gshan@redhat.com>,
Ricardo Koller <ricarkol@google.com>,
Raghavendra Rao Ananta <rananta@google.com>,
Ryan Roberts <ryan.roberts@arm.com>,
David Rientjes <rientjes@google.com>,
Axel Rasmussen <axelrasmussen@google.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
kvm@vger.kernel.org, linux-mm@kvack.org,
linux-trace-kernel@vger.kernel.org
Subject: Re: [PATCH v3 6/7] KVM: arm64: Participate in bitmap-based PTE aging
Date: Tue, 2 Apr 2024 00:00:12 -0700 [thread overview]
Message-ID: <Zgus_A_cJ68f6glV@linux.dev> (raw)
In-Reply-To: <CAOUHufaQ-g6L5roB-3K0GamuS3p9ACpPj9XM-NF67GgrjoTj_A@mail.gmail.com>
On Tue, Apr 02, 2024 at 12:06:56AM -0400, Yu Zhao wrote:
> On Mon, Apr 1, 2024 at 7:30 PM James Houghton <jthoughton@google.com> wrote:
> > Suggested-by: Yu Zhao <yuzhao@google.com>
>
> Thanks but I did not suggest this.
Entirely up to you, but I would still want to credit everyone who
contributed to a feature even if the underlying implementation has
changed since the original attempt.
> What I have in v2 is RCU based. I hope Oliver or someone else can help
> make that work.
Why? If there's data to show that RCU has a material benefit over taking
the MMU lock for read then I'm all for it. Otherwise, the work required
to support page-table walkers entirely outside of the MMU lock isn't
justified.
In addition to ensuring that page table teardown is always RCU-safe,
we'd need to make sure all of the walkers that take the write lock are
prepared to handle races.
> Otherwise we can just drop this for now and revisit
> later.
I really wouldn't get hung up on the locking as the make-or-break for
whether arm64 supports this MMU notifier.
--
Thanks,
Oliver
next prev parent reply other threads:[~2024-04-02 7:00 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-01 23:29 [PATCH v3 0/7] mm/kvm: Improve parallelism for access bit harvesting James Houghton
2024-04-01 23:29 ` [PATCH v3 1/7] mm: Add a bitmap into mmu_notifier_{clear,test}_young James Houghton
2024-04-04 18:52 ` David Hildenbrand
2024-04-09 18:31 ` James Houghton
2024-04-09 19:35 ` David Hildenbrand
2024-04-11 0:35 ` James Houghton
2024-04-12 18:45 ` David Matlack
2024-04-19 20:34 ` James Houghton
2024-04-01 23:29 ` [PATCH v3 2/7] KVM: Move MMU notifier function declarations James Houghton
2024-04-01 23:29 ` [PATCH v3 3/7] KVM: Add basic bitmap support into kvm_mmu_notifier_test/clear_young James Houghton
2024-04-12 20:28 ` David Matlack
2024-04-19 20:41 ` James Houghton
2024-04-01 23:29 ` [PATCH v3 4/7] KVM: x86: Move tdp_mmu_enabled and shadow_accessed_mask James Houghton
2024-04-01 23:29 ` [PATCH v3 5/7] KVM: x86: Participate in bitmap-based PTE aging James Houghton
2024-04-11 17:08 ` David Matlack
2024-04-11 17:28 ` David Matlack
2024-04-11 18:00 ` David Matlack
2024-04-11 18:07 ` David Matlack
2024-04-19 20:47 ` James Houghton
2024-04-19 21:06 ` David Matlack
2024-04-19 21:48 ` James Houghton
2024-04-21 0:19 ` Yu Zhao
2024-04-12 20:44 ` David Matlack
2024-04-19 20:54 ` James Houghton
2024-04-01 23:29 ` [PATCH v3 6/7] KVM: arm64: " James Houghton
2024-04-02 4:06 ` Yu Zhao
2024-04-02 7:00 ` Oliver Upton [this message]
2024-04-02 7:33 ` Marc Zyngier
2024-04-01 23:29 ` [PATCH v3 7/7] mm: multi-gen LRU: use mmu_notifier_test_clear_young() James Houghton
2024-04-12 18:41 ` [PATCH v3 0/7] mm/kvm: Improve parallelism for access bit harvesting David Matlack
2024-04-19 20:57 ` James Houghton
2024-04-19 22:23 ` Oliver Upton
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