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Date: Wed, 7 Jan 2026 08:51:22 +0530
From: Linu Cherian <linu.cherian@arm.com>
To: Ryan Roberts <ryan.roberts@arm.com>
Cc: Will Deacon <will@kernel.org>, Ard Biesheuvel <ardb@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
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Subject: Re: [PATCH v1 11/13] arm64: mm: More flags for __flush_tlb_range()
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References: <20251216144601.2106412-1-ryan.roberts@arm.com>
 <20251216144601.2106412-12-ryan.roberts@arm.com>
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In-Reply-To: <20251216144601.2106412-12-ryan.roberts@arm.com>

Ryan,

On Tue, Dec 16, 2025 at 02:45:56PM +0000, Ryan Roberts wrote:
> Refactor function variants with "_nosync", "_local" and "_nonotify" into
> a single __always_inline implementation that takes flags and rely on
> constant folding to select the parts that are actually needed at any
> given callsite, based on the provided flags.
> 
> Flags all live in the tlbf_t (TLB flags) type; TLBF_NONE (0) continues
> to provide the strongest semantics (i.e. evict from walk cache,
> broadcast, synchronise and notify). Each flag reduces the strength in
> some way; TLBF_NONOTIFY, TLBF_NOSYNC and TLBF_NOBROADCAST are added to
> complement the existing TLBF_NOWALKCACHE.

It would be nice to have some notes added on the below for better clarity 
* What a walk cache is and why we bother about them ?
* Why and how should we invalidate the walk caches ?

--
Linu Cherian.