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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,HK_RANDOM_FROM,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 711E3C2D0E2 for ; Tue, 22 Sep 2020 08:24:12 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C5DF823A1E for ; Tue, 22 Sep 2020 08:24:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C5DF823A1E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id CB31B900037; Tue, 22 Sep 2020 04:24:10 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C3C43900036; Tue, 22 Sep 2020 04:24:10 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B05AA900037; Tue, 22 Sep 2020 04:24:10 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0124.hostedemail.com [216.40.44.124]) by kanga.kvack.org (Postfix) with ESMTP id 94FF6900036 for ; Tue, 22 Sep 2020 04:24:10 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 60C9F1EF1 for ; Tue, 22 Sep 2020 08:24:10 +0000 (UTC) X-FDA: 77290009860.20.town60_51057642714c Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin20.hostedemail.com (Postfix) with ESMTP id 4112C180C07A3 for ; Tue, 22 Sep 2020 08:24:10 +0000 (UTC) X-HE-Tag: town60_51057642714c X-Filterd-Recvd-Size: 3526 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by imf10.hostedemail.com (Postfix) with ESMTP for ; Tue, 22 Sep 2020 08:24:09 +0000 (UTC) IronPort-SDR: Dtw8AMzsfJlOTrw8UqwyrQsuWE+VGeg4gZqWLYEvIzfYVCQ5oX8NoYmyskOIgBoMol9B7PV9d/ rnfxCPXji0eA== X-IronPort-AV: E=McAfee;i="6000,8403,9751"; a="161485974" X-IronPort-AV: E=Sophos;i="5.77,290,1596524400"; d="scan'208";a="161485974" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Sep 2020 01:24:08 -0700 IronPort-SDR: hYPYeshgQ9gLbxA+nGdC2UUT7a+sUMfvmmOdnILx1oZilih/OM+HLuWniJZ+KnDxCiUxxvah+K LMJGx+/weQGQ== X-IronPort-AV: E=Sophos;i="5.77,290,1596524400"; d="scan'208";a="454404248" Received: from atroib-mobl2.ger.corp.intel.com (HELO [10.214.238.184]) ([10.214.238.184]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Sep 2020 01:24:02 -0700 Subject: Re: [Intel-gfx] [PATCH 3/6] drm/i915: use vmap in shmem_pin_map To: Christoph Hellwig , Matthew Wilcox Cc: Juergen Gross , Stefano Stabellini , linux-mm@kvack.org, Peter Zijlstra , Boris Ostrovsky , x86@kernel.org, linux-kernel@vger.kernel.org, Minchan Kim , dri-devel@lists.freedesktop.org, xen-devel@lists.xenproject.org, Andrew Morton , intel-gfx@lists.freedesktop.org, Nitin Gupta , Chris Wilson , Matthew Auld References: <20200918163724.2511-1-hch@lst.de> <20200918163724.2511-4-hch@lst.de> <20200921191157.GX32101@casper.infradead.org> <20200922062249.GA30831@lst.de> From: Tvrtko Ursulin Organization: Intel Corporation UK Plc Message-ID: <43d10588-2033-038b-14e4-9f41cd622d7b@linux.intel.com> Date: Tue, 22 Sep 2020 09:23:59 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200922062249.GA30831@lst.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit 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 22/09/2020 07:22, Christoph Hellwig wrote: > On Mon, Sep 21, 2020 at 08:11:57PM +0100, Matthew Wilcox wrote: >> This is awkward. I'd like it if we had a vfree() variant which called >> put_page() instead of __free_pages(). I'd like it even more if we >> used release_pages() instead of our own loop that called put_page(). > > Note that we don't need a new vfree variant, we can do this manually if > we want, take a look at kernel/dma/remap.c. But I thought this code > intentionally doesn't want to do that to avoid locking in the memory > for the pages array. Maybe the i915 maintainers can clarify. + Chris & Matt who were involved with this part of i915. If I understood this sub-thread correctly, iterating and freeing the pages via the vmapped ptes, so no need for a shmem_read_mapping_page_gfp loop in shmem_unpin_map looks plausible to me. I did not get the reference to kernel/dma/remap.c though, and also not sure how to do the error unwind path in shmem_pin_map at which point the allocated vm area hasn't been fully populated yet. Hand-roll the loop walking vm area struct in there? Regards, Tvrtko