linux-kernel - Re: [PATCH 0/2] KVM: Protect vCPU's PID with a rwlock

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Message-ID: <ZrKqzrPF_y4momna@linux.dev>
Date: Tue, 6 Aug 2024 15:59:26 -0700
From: Oliver Upton <oliver.upton@...ux.dev>
To: Sean Christopherson <seanjc@...gle.com>
Cc: Marc Zyngier <maz@...nel.org>, Paolo Bonzini <pbonzini@...hat.com>,
	linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev,
	kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
	Steve Rutherford <srutherford@...gle.com>
Subject: Re: [PATCH 0/2] KVM: Protect vCPU's PID with a rwlock

On Fri, Aug 02, 2024 at 01:01:34PM -0700, Sean Christopherson wrote:
> Protect vcpu->pid with a rwlock instead of RCU, so that running a vCPU
> with a different task doesn't require a full RCU synchronization, which
> can introduce a non-trivial amount of jitter, especially on large systems.
> 
> I've had this mini-series sitting around for ~2 years, pretty much as-is.
> I could have sworn past me thought there was a flaw in using a rwlock, and
> so I never posted it, but for the life of me I can't think of any issues.
> 
> Extra eyeballs would be much appreciated.

Besides the nitpicks:

Acked-by: Oliver Upton <oliver.upton@...ux.dev>

-- 
Thanks,
Oliver