linux-kernel - Re: [PATCH v8 0/4] Initial BBML2 support for contpte

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Message-Id: <175130394786.1397341.8393706123668185892.b4-ty@arm.com>
Date: Mon, 30 Jun 2025 18:19:14 +0100
From: Catalin Marinas <catalin.marinas@....com>
To: ryan.roberts@....com,
	yang@...amperecomputing.com,
	will@...nel.org,
	jean-philippe@...aro.org,
	robin.murphy@....com,
	joro@...tes.org,
	maz@...nel.org,
	oliver.upton@...ux.dev,
	joey.gouly@....com,
	james.morse@....com,
	broonie@...nel.org,
	ardb@...nel.org,
	baohua@...nel.org,
	suzuki.poulose@....com,
	david@...hat.com,
	jgg@...pe.ca,
	nicolinc@...dia.com,
	jsnitsel@...hat.com,
	mshavit@...gle.com,
	kevin.tian@...el.com,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	iommu@...ts.linux.dev,
	Mikołaj Lenczewski <miko.lenczewski@....com>
Subject: Re: [PATCH v8 0/4] Initial BBML2 support for contpte_convert()

On Wed, 25 Jun 2025 11:34:31 +0000, Mikołaj Lenczewski wrote:
> This patch series extends the cpufeature framework to add support for
> easily matching against all early cpus, and builds on this to add initial
> support for eliding Break-Before-Make requirements on systems that support
> BBML2 and additionally guarantee to never raise a conflict abort.
> 
> This support conceptually reorders and then elides both a TLB invalidation
> and a DSB in contpte_convert(), when BBML2 is supported. This leads to
> a 12% improvement when executing a microbenchmark designed to force the
> pathological path where contpte_convert() gets called. This represents
> an 80% reduction in the cost of calling contpte_convert().
> 
> [...]

Applied to arm64 (for-next/user-contig-bbml2), thanks!

[1/4] arm64: cpufeature: Introduce MATCH_ALL_EARLY_CPUS capability type
      https://git.kernel.org/arm64/c/3eb06f6ce3af
[2/4] arm64: Add BBM Level 2 cpu feature
      https://git.kernel.org/arm64/c/5aa4b625762e
[3/4] iommu/arm: Add BBM Level 2 smmu feature
      https://git.kernel.org/arm64/c/212c439bdd8f
[4/4] arm64/mm: Elide tlbi in contpte_convert() under BBML2
      https://git.kernel.org/arm64/c/83bbd6be7d17

-- 
Catalin