From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B6A0EC43219 for ; Fri, 25 Nov 2022 15:49:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229590AbiKYPtv (ORCPT ); Fri, 25 Nov 2022 10:49:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37026 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229529AbiKYPtu (ORCPT ); Fri, 25 Nov 2022 10:49:50 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C0BAC23381; Fri, 25 Nov 2022 07:49:49 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 54C8E6251A; Fri, 25 Nov 2022 15:49:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F8C2C433D7; Fri, 25 Nov 2022 15:49:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1669391388; bh=J1n7A3Po/BvjIiR1JkMUhIHi/MIjb2B5HBeJvLmwlrc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=IlJkXvd6UD0q9KHrp0K6eTAKTW+cDf93ng3pAFhU8yb2+8+Q2Xs0wtEAT6fCUkjj5 oZhNQoGestw7q/77t7S1TOKFWod64jyhVQzayoGxCppnVhIfn7WUkBl9Fh/Qa2NX2k 8nGl86ofw2ut2ByiUSDWTmrhXWVDljsV7RYZTltgGuLH/B4flQYbZnTGJrR02M4u++ g+2CSHQhFFq9GwUXKT0UWMTvG4D2u95+0tAt73qLX9FXLxRE5w+hy5hNq+ocm8pVE7 kEn6KL3kEcUENP0VM41/1pbKahH7k9fN+psf3fjR1BkdkwngmdBpPPezz+Al+vVqHt EZZ65d3HUhF8Q== Received: from johan by xi.lan with local (Exim 4.94.2) (envelope-from ) id 1oyax9-0006Zf-7R; Fri, 25 Nov 2022 16:49:23 +0100 Date: Fri, 25 Nov 2022 16:49:23 +0100 From: Johan Hovold To: Manivannan Sadhasivam Cc: Johan Hovold , Bjorn Andersson , Andy Gross , Konrad Dybcio , Rob Herring , Krzysztof Kozlowski , Will Deacon , Robin Murphy , Christoph Hellwig , Ard Biesheuvel , Catalin Marinas , linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64: dts: qcom: sc8280xp: fix PCIe DMA coherency Message-ID: References: <20221124142501.29314-1-johan+linaro@kernel.org> <20221125142625.GA9892@thinkpad> <20221125145336.GB9892@thinkpad> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221125145336.GB9892@thinkpad> Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Fri, Nov 25, 2022 at 08:23:36PM +0530, Manivannan Sadhasivam wrote: > On Fri, Nov 25, 2022 at 03:43:59PM +0100, Johan Hovold wrote: > > On Fri, Nov 25, 2022 at 07:56:25PM +0530, Manivannan Sadhasivam wrote: > > > On Thu, Nov 24, 2022 at 03:25:01PM +0100, Johan Hovold wrote: > > I never claimed it would fix the problem, I explicitly wrote that it > > made it less likely to occur (to the point where my reproducer no longer > > triggers). > > > Increasing the buffer sizes to two pages to force CMA allocation also appears > > to make the problem go away. > > The "go away" part sounded like a claim to me and hence I added the statement. > But no worries :) Hopefully it's clear enough if you also read the preceding sentence (with emphasis added): presumably as these queues are small enough to not be allocated using CMA which in turn make them *more likely to be cached* (e.g. due to accesses to nearby pages through the cacheable linear map). Johan