linux-kernel - Re: [PATCH 3/3] x86/mm: Clarify should_flush

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Message-ID: <6d798978-753b-4236-a24d-51c9a414f64b@intel.com>
Date: Fri, 23 May 2025 10:23:40 -0700
From: Dave Hansen <dave.hansen@...el.com>
To: Peter Zijlstra <peterz@...radead.org>, x86@...nel.org
Cc: linux-kernel@...r.kernel.org, kys@...rosoft.com, haiyangz@...rosoft.com,
 wei.liu@...nel.org, decui@...rosoft.com, tglx@...utronix.de,
 mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com, hpa@...or.com,
 luto@...nel.org, linux-hyperv@...r.kernel.org
Subject: Re: [PATCH 3/3] x86/mm: Clarify should_flush_tlb() ordering

On 5/20/25 03:55, Peter Zijlstra wrote:
> The ordering in should_flush_tlb() is entirely non-obvious and is only
> correct because x86 is TSO. Clarify the situation by replacing two
> WRITE_ONCE()s with smp_store_release(), which on x86 is cosmetic.
> 
> Additionally, clarify the comment on should_flush_tlb().

Thanks for clarifying the ordering in those comments. It's much
appreciated by us mere mortals!

Oh, and there are a few we's that snuck into the comments. But whoever
applies this can fix them up.

Acked-by: Dave Hansen <dave.hansen@...ux.intel.com>