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 89787C7EE2E for ; Wed, 7 Jun 2023 21:00:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235858AbjFGVAx (ORCPT ); Wed, 7 Jun 2023 17:00:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33686 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236157AbjFGVAZ (ORCPT ); Wed, 7 Jun 2023 17:00:25 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 734CE2109 for ; Wed, 7 Jun 2023 14:00:04 -0700 (PDT) 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 3B1E2648CC for ; Wed, 7 Jun 2023 21:00:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2252BC433D2; Wed, 7 Jun 2023 21:00:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1686171602; bh=K7QsNx354p5UJb+W0jt0jJmIo1DtPxXeGq1FHy48xWw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=KTNvxPinFizEuJn1y1ca+OL7HSvTz45fSL1nS4DIvD+mRfKBSBF+XQsXofn0uAWLw Cm9GZS4khbbCdQlp00yyEJPPiS6HTZ5LXu/afx0eqEv2zq4yCcTz2jcQkzb3crBfLf mwoI4754n1XsqP8Oqd8DCAaT0ZMyvzV3fKt5xAJg= Date: Wed, 7 Jun 2023 14:00:01 -0700 From: Andrew Morton To: Mike Kravetz Cc: Gerd Hoffmann , Junxiao Chang , kirill.shutemov@linux.intel.com, mhocko@suse.com, jmarchan@redhat.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, muchun.song@linux.dev, Vivek Kasireddy , Dongwon Kim , James Houghton , dri-devel@lists.freedesktop.org, Greg Kroah-Hartman Subject: Re: [PATCH] mm: fix hugetlb page unmap count balance issue Message-Id: <20230607140001.6685b0a058511f125a005da4@linux-foundation.org> In-Reply-To: <20230607205310.GA4122@monkey> References: <20230512072036.1027784-1-junxiao.chang@intel.com> <20230512232947.GA3927@monkey> <20230515170259.GA3848@monkey> <20230516223440.GA30624@monkey> <20230607120312.6da5cea7677ec1a3da35b92c@linux-foundation.org> <20230607205310.GA4122@monkey> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 7 Jun 2023 13:53:10 -0700 Mike Kravetz wrote: > > > > BUGs aren't good. Can we please find a way to push this along? > > > > Have we heard anything from any udmabuf people? > > > > I have not heard anything. When this issue popped up, it took me by surprise. > > udmabuf maintainer (Gerd Hoffmann), the people who added hugetlb support and > the list where udmabuf was developed (dri-devel@lists.freedesktop.org) have > been on cc. Maybe Greg can suggest a way forward. > My 'gut reaction' would be to remove hugetlb support from udmabuf. From a > quick look, if we really want this support then there will need to be some > API changes. For example UDMABUF_CREATE should be hugetlb page aligned > and a multiple of hugetlb page size if using a hugetlb mapping. > > It would be good to know about users of the driver. So disabling "hugetlb=on" (and adding an explanatory printk) would suffice for now?