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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 59806EB64DC for ; Thu, 20 Jul 2023 06:52:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=39zI4xQyfxNMu7zh69tWbB0How5y2k3MK8vkjXIn4F8=; b=QCPulFzupNG2uk iij+L3aN6kiz9lgB2ud4C7JqdOSVT6XbeFWhZ2YvNRkwVAWEeusmeMFIBC4NIm0mFNsujXmFoQ2ns /PBGW3QDtvDBamRioke+E5zZxbRsoRR2YwgqKZlYn+U8ShAzUAMnSUFqu/lvD6+WlSRALXHBLy1K3 m9sqZtViG3W9PdhO2RI+jhyBYwO2Oe2zLxofj2W9UorrdgzTXhCs6cpFcxOPk6wo9OUZTU78g+eNU QmY/FMA6oPr2wLg1pcxOepQ0aRkW0W04OsW4wgwf4ZnvuC4KWSTMIGygbp9A41Qi6cbWW6FotA7mv VouUTRgIVHv0L7jFg1pQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qMNWS-00A0Pi-08; Thu, 20 Jul 2023 06:52:24 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qMNWP-00A0Ov-1p for linux-arm-kernel@lists.infradead.org; Thu, 20 Jul 2023 06:52:22 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 666CB67373; Thu, 20 Jul 2023 08:52:16 +0200 (CEST) Date: Thu, 20 Jul 2023 08:52:16 +0200 From: Christoph Hellwig To: Petr Tesarik Cc: Stefano Stabellini , Russell King , Thomas Bogendoerfer , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , "H. Peter Anvin" , Greg Kroah-Hartman , "Rafael J. Wysocki" , Juergen Gross , Oleksandr Tyshchenko , Christoph Hellwig , Marek Szyprowski , Robin Murphy , Petr Tesarik , Jonathan Corbet , Andy Shevchenko , Hans de Goede , James Seo , James Clark , Kees Cook , "moderated list:XEN HYPERVISOR ARM" , "moderated list:ARM PORT" , open list , "open list:MIPS" , "open list:XEN SWIOTLB SUBSYSTEM" , Roberto Sassu , Kefeng Wang , petr@tesarici.cz Subject: Re: [PATCH v4 0/8] Allow dynamic allocation of software IO TLB bounce buffers Message-ID: <20230720065216.GB4395@lst.de> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230719_235221_747176_542D8B67 X-CRM114-Status: GOOD ( 15.22 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Just to add a highlevel comment here after I feel like I need a little more time to review the guts. I'm still pretty concerned about the extra list that needs to be consulted in is_swiotlb_buffer, but I can't really think of anything better. Maybe an xarray has better cache characteristics, but that one requires even more allocations in the low-level dma map path. One thing I'd like to see for the next version is to make the new growing code a config option at least for now. It is a pretty big change of the existing swiotlb behavior, and I want people to opt into it conciously. Maybe we can drop the option again after a few years once everything has settled. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel