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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 B1693C4332B for ; Tue, 24 Mar 2020 07:33:43 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 85DCC20719 for ; Tue, 24 Mar 2020 07:33:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 85DCC20719 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1066F6B00DC; Tue, 24 Mar 2020 03:33:43 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0B7176B00DD; Tue, 24 Mar 2020 03:33:43 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F0E606B00DE; Tue, 24 Mar 2020 03:33:42 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0171.hostedemail.com [216.40.44.171]) by kanga.kvack.org (Postfix) with ESMTP id D67DF6B00DC for ; Tue, 24 Mar 2020 03:33:42 -0400 (EDT) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 346A7B2AF for ; Tue, 24 Mar 2020 07:33:43 +0000 (UTC) X-FDA: 76629441126.13.money13_206fcf3b3f458 X-HE-Tag: money13_206fcf3b3f458 X-Filterd-Recvd-Size: 2011 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf28.hostedemail.com (Postfix) with ESMTP for ; Tue, 24 Mar 2020 07:33:42 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 6019368BFE; Tue, 24 Mar 2020 08:33:39 +0100 (CET) Date: Tue, 24 Mar 2020 08:33:39 +0100 From: Christoph Hellwig To: Jason Gunthorpe Cc: Jerome Glisse , Ralph Campbell , Felix.Kuehling@amd.com, linux-mm@kvack.org, John Hubbard , dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, Christoph Hellwig , Philip Yang , Jason Gunthorpe Subject: Re: [PATCH v2 hmm 4/9] mm/hmm: remove HMM_FAULT_SNAPSHOT Message-ID: <20200324073339.GC23447@lst.de> References: <20200324011457.2817-1-jgg@ziepe.ca> <20200324011457.2817-5-jgg@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200324011457.2817-5-jgg@ziepe.ca> User-Agent: Mutt/1.5.17 (2007-11-01) 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: > > +/* > + * If the valid flag is masked off, and default_flags doesn't set valid, then > + * hmm_pte_need_fault() always returns 0. > + */ > +static bool hmm_can_fault(struct hmm_range *range) > +{ > + return ((range->flags[HMM_PFN_VALID] & range->pfn_flags_mask) | > + range->default_flags) & > + range->flags[HMM_PFN_VALID]; > +} So my idea behind the helper was to turn this into something readable :) E.g. /* * We only need to fault if either the default mask requires to fault all * pages, or at least the mask allows for individual pages to be faulted. */ static bool hmm_can_fault(struct hmm_range *range) { return ((range->default_flags | range->pfn_flags_mask) & range->flags[HMM_PFN_VALID]); } In fact now that I managed to destill it down to this I'm not even sure we really even need the helper, although the comment really helps.