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X-CSE-ConnectionGUID: D9ubyC/0SqCFVMZ8lY32FQ== X-CSE-MsgGUID: enEvAgF7RX+98JXyi9fCGA== X-IronPort-AV: E=McAfee;i="6700,10204,11441"; a="49202549" X-IronPort-AV: E=Sophos;i="6.15,309,1739865600"; d="scan'208";a="49202549" Received: from orviesa007.jf.intel.com ([10.64.159.147]) by fmvoesa113.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 May 2025 10:23:41 -0700 X-CSE-ConnectionGUID: n3YprIrCTvi2+c5lKrRh5w== X-CSE-MsgGUID: NjtfXbe7RfOC0hDStA/1BA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.15,309,1739865600"; d="scan'208";a="141782487" Received: from msatwood-mobl.amr.corp.intel.com (HELO [10.125.109.147]) ([10.125.109.147]) by orviesa007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 May 2025 10:23:42 -0700 Message-ID: <6d798978-753b-4236-a24d-51c9a414f64b@intel.com> Date: Fri, 23 May 2025 10:23:40 -0700 Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 3/3] x86/mm: Clarify should_flush_tlb() ordering To: Peter Zijlstra , x86@kernel.org Cc: linux-kernel@vger.kernel.org, kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, luto@kernel.org, linux-hyperv@vger.kernel.org References: <20250520105542.283166629@infradead.org> <20250520110632.280908218@infradead.org> From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; 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charset=UTF-8 Content-Transfer-Encoding: 7bit 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