From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D646122129B; Tue, 24 Feb 2026 10:41:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771929707; cv=none; b=O8t6RgzRgnuTLEPKxjqKtRYxBKXQJkn7YO33TiBoMTY3MH8hzF73BGmk0JsMc9dxR4xJkQ3kBtxxuRTX3IEnSy2UtFglPWEAFUDQPVFhw1JmRv+oVXEkrfsjKd2MCDKylFmBDM5wadK3UAwg1mI5SBIuOtcSP7DYZQ4ryvts6K0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771929707; c=relaxed/simple; bh=wg8+qeLkHaKWQnLiQzpCNPEf5hQSXuJ49gxIF/7p/Z0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=fIaYF+1YO2RP9i/K8wdr76jXzWkaxdaVNosl/cJpYZXtCzqWzG36aufvjlriuOTx9VF/ONsnU2RcEhWAw8s+Sx7qUwOR62T5YZDq8JI0xwXV1Te6uuV+VYai2S2KMLQ4zeqcrPMKZtgyj//gbu1DBXDbQFDIV4QmDz9U5tfEJlg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=YxkdXSBf; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="YxkdXSBf" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=bHwIF4V+Sfi2Dx/bo9vGSSFFbaqINJ//nOO1nfy3NhA=; b=YxkdXSBfv2J0CfNjCaNSNGxjsW HimhZAuJW4NO5YY8NK+llCUJeoqBRJ6Vn99JrFQjLTPSc32v5+H796fnEtoAEERJu7CHuuyt5Cq8q mgkfSXvXgGGNAMbbP68DvycGfejyRyfC64MxJw9nNRjI0SvikEy3mWLxWQSe7Gu6xvJjU6HWvmk74 ChIW3W7MiMNHXPnbNOiICk5WzeaKFt1R0vsVGtgLzbNfJya6kUHttZIABiuipFnYmSVOIcKpFmkzN iY/HvUJjMn6/HhwyMGbK/YmZ1wOzC70WbrcIRbXBS9kJQEVEjXPYuE6ykoiI3MMcHusmIGp+/IeDl CVZfzgXw==; Received: from 2001-1c00-8d85-5700-266e-96ff-fe07-7dcc.cable.dynamic.v6.ziggo.nl ([2001:1c00:8d85:5700:266e:96ff:fe07:7dcc] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1vuprD-0000000Gh6J-17U0; Tue, 24 Feb 2026 10:41:35 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 0DEC930075A; Tue, 24 Feb 2026 11:41:34 +0100 (CET) Date: Tue, 24 Feb 2026 11:41:34 +0100 From: Peter Zijlstra To: Mark Rutland Cc: Anshuman Khandual , linux-arm-kernel@lists.infradead.org, Catalin Marinas , Will Deacon , Ryan Roberts , Lorenzo Stoakes , Andrew Morton , David Hildenbrand , Mike Rapoport , Linu Cherian , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , linux-perf-users@vger.kernel.org Subject: Re: [RFC V1 04/16] perf/events: Replace READ_ONCE() with standard pgtable accessors Message-ID: <20260224104134.GW1395266@noisy.programming.kicks-ass.net> References: <20260224051153.3150613-1-anshuman.khandual@arm.com> <20260224051153.3150613-5-anshuman.khandual@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Feb 24, 2026 at 10:08:21AM +0000, Mark Rutland wrote: > On Tue, Feb 24, 2026 at 10:41:41AM +0530, Anshuman Khandual wrote: > > Replace READ_ONCE() with standard page table accessors i.e pxdp_get() which > > anyways default into READ_ONCE() in cases where platform do not override. > > For each of the patches where you make this sort of change, please > explain in the commit message *why* it is necessary to do this. > > IIUC the entire point of this is that in subsequent patches, arm64 will > need to use something other than READ_ONCE() for all pXX levels in order > to support D128 translation tables. > > Spelling that out in the commit message makes it much easier for > reviewers to see what's going on, and to focus any discussion/questions, > e.g. *why* won't READ_ONCE() work? That, and only being sent *one* patch, I have no clue what the rest of them are doing. Didn't even get 0/n. I hate people sending me just one patch; just send the whole series already.