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 X-Spam-Level: X-Spam-Status: No, score=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B730EC2D0C0 for ; Mon, 9 Dec 2019 07:54:25 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7325620726 for ; Mon, 9 Dec 2019 07:54:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="cdeQwFjY" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7325620726 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id ECDB56B2595; Mon, 9 Dec 2019 02:54:24 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E7DEA6B2596; Mon, 9 Dec 2019 02:54:24 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D93E16B2597; Mon, 9 Dec 2019 02:54:24 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0069.hostedemail.com [216.40.44.69]) by kanga.kvack.org (Postfix) with ESMTP id BFBFE6B2595 for ; Mon, 9 Dec 2019 02:54:24 -0500 (EST) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 4AFB68249980 for ; Mon, 9 Dec 2019 07:54:24 +0000 (UTC) X-FDA: 76244840448.17.grade18_94e295f93948 X-HE-Tag: grade18_94e295f93948 X-Filterd-Recvd-Size: 4260 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf10.hostedemail.com (Postfix) with ESMTP for ; Mon, 9 Dec 2019 07:54:23 +0000 (UTC) Received: from rapoport-lnx (nesher1.haifa.il.ibm.com [195.110.40.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0EAA2206D3; Mon, 9 Dec 2019 07:54:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575878063; bh=l5RNIqY71fgRQ4gflWGJ6VKGFQXsfgVwTeBzBRWCnmA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=cdeQwFjYFMVzFUr+WBxPM2UoXcUM34dHDHDlXse6W6pGhUNw4fXvyRJZsZxwoSt7e /90E+MSe4ehpwRUS2sdbf77ubqB8d1DrkO2CSKEuGO9YsT9AvJPnhG7JbgbZEksY6H qnqAaymyoD4xlJ8PxUL70giW5qfYCn6C8GYHBKGs= Date: Mon, 9 Dec 2019 09:54:15 +0200 From: Mike Rapoport To: Michael Ellerman Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, Mike Rapoport , Christian Zigotzky , Benjamin Herrenschmidt , Christoph Hellwig , Darren Stevens , mad skateman , Nicolas Saenz Julienne , Paul Mackerras , Robin Murphy , Rob Herring Subject: Re: [PATCH] powerpc: ensure that swiotlb buffer is allocated from low memory Message-ID: <20191209075413.GA4137@rapoport-lnx> References: <20191204123524.22919-1-rppt@kernel.org> <87h82aqcju.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87h82aqcju.fsf@mpe.ellerman.id.au> User-Agent: Mutt/1.5.24 (2015-08-30) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Dec 09, 2019 at 04:43:17PM +1100, Michael Ellerman wrote: > Mike Rapoport writes: > > From: Mike Rapoport > > > > Some powerpc platforms (e.g. 85xx) limit DMA-able memory way below 4G. If a > > system has more physical memory than this limit, the swiotlb buffer is not > > addressable because it is allocated from memblock using top-down mode. > > > > Force memblock to bottom-up mode before calling swiotlb_init() to ensure > > that the swiotlb buffer is DMA-able. > > > > Link: https://lkml.kernel.org/r/F1EBB706-73DF-430E-9020-C214EC8ED5DA@xenosoft.de > > This wasn't bisected, but I thought it was a regression. Do we know what > commit caused it? > > Was it 25078dc1f74b ("powerpc: use mm zones more sensibly") ? swiotlb buffer is initialized before zones are actually used, so probably not :) > Or was that a red herring? > > cheers > > > Reported-by: Christian Zigotzky > > Signed-off-by: Mike Rapoport > > Cc: Benjamin Herrenschmidt > > Cc: Christoph Hellwig > > Cc: Darren Stevens > > Cc: mad skateman > > Cc: Michael Ellerman > > Cc: Nicolas Saenz Julienne > > Cc: Paul Mackerras > > Cc: Robin Murphy > > Cc: Rob Herring > > --- > > arch/powerpc/mm/mem.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c > > index be941d382c8d..14c2c53e3f9e 100644 > > --- a/arch/powerpc/mm/mem.c > > +++ b/arch/powerpc/mm/mem.c > > @@ -260,6 +260,14 @@ void __init mem_init(void) > > BUILD_BUG_ON(MMU_PAGE_COUNT > 16); > > > > #ifdef CONFIG_SWIOTLB > > + /* > > + * Some platforms (e.g. 85xx) limit DMA-able memory way below > > + * 4G. We force memblock to bottom-up mode to ensure that the > > + * memory allocated in swiotlb_init() is DMA-able. > > + * As it's the last memblock allocation, no need to reset it > > + * back to to-down. > > + */ > > + memblock_set_bottom_up(true); > > swiotlb_init(0); > > #endif > > > > -- > > 2.24.0 -- Sincerely yours, Mike.