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=-7.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, 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 E9109C43333 for ; Wed, 10 Mar 2021 17:59:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BF1BA64FB1 for ; Wed, 10 Mar 2021 17:59:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233916AbhCJR7E (ORCPT ); Wed, 10 Mar 2021 12:59:04 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:45078 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233701AbhCJR6g (ORCPT ); Wed, 10 Mar 2021 12:58:36 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1615399115; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=sN3rfVQ5mWC4zIRNCuy+nBt59u74/cvs2MbFtdHtVIo=; b=gRXIYb65oiTZe30KM1Z5sq3rfJqW4CLsMNBU6jmVGG0jJCZFW4Knwf9lp7Pu1SJ6D2ZCoQ QOT0u7sW71l2fWqa/ju1EuEHswfrM5Kea2r8aCUwMFQv+M2HSdVm1NuBk0nbL0rmPPOhL9 V6//Y4HrLXmIcI0ipGwiO0Tx9tvmzP4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-396-_wKzQ_dVNDOyILlTmxpsVw-1; Wed, 10 Mar 2021 12:58:31 -0500 X-MC-Unique: _wKzQ_dVNDOyILlTmxpsVw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 02E9657; Wed, 10 Mar 2021 17:58:30 +0000 (UTC) Received: from [10.36.112.107] (ovpn-112-107.ams2.redhat.com [10.36.112.107]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5DA4718C7A; Wed, 10 Mar 2021 17:58:27 +0000 (UTC) To: Oscar Salvador Cc: Andrew Morton , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H . Peter Anvin" , Michal Hocko , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20210309174113.5597-1-osalvador@suse.de> <20210309174113.5597-4-osalvador@suse.de> <3471fe0e-d8f4-c8fe-2096-8d9c8b1ab5bc@redhat.com> <20210310174953.GA16289@linux> From: David Hildenbrand Organization: Red Hat GmbH Subject: Re: [PATCH v5 3/4] x86/vmemmap: Handle unpopulated sub-pmd ranges Message-ID: <1814c21c-b822-0ec6-c16d-92424d00663a@redhat.com> Date: Wed, 10 Mar 2021 18:58:26 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: <20210310174953.GA16289@linux> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10.03.21 18:49, Oscar Salvador wrote: > On Tue, Mar 09, 2021 at 06:52:38PM +0100, David Hildenbrand wrote: >>> -#define PAGE_INUSE 0xFD >>> +#ifdef CONFIG_SPARSEMEM_VMEMMAP >>> +#define PAGE_UNUSED 0xFD >>> + >>> +/* Returns true if the PMD is completely unused and thus it can be freed */ >>> +static bool __meminit vmemmap_pmd_is_unused(unsigned long addr, unsigned long end) >>> +{ >> >> I don't think the new name is any better. It implies that all it does is a >> check - yet it actually clears the given range. (I prefer the old name, but >> well, I came up with that, so what do I know :D ) > > Sorry, I did not mean to offend here. Oh, I didn't feel offended - I was rather expressing that my opinion might be biased because I came up with these names in the s390x variant ;) > > Something like: vmemmap_is_pmd_unused_after_clearing_it would be a bit better > I guess. > Tbh, both this and previous one looked fine to me, but I understand where Dave > confusion was coming from, that is why I decided to rename it. > > Maybe a middle-ground would have been to expand the comment above. Thinking again, I guess it might be a good idea to factor out the core functions into common code. For the optimization part, it might make sense too pass some "state" structure that contains e.g., "unused_pmd_start". Then we don't have diverging implementations of essentially the same thing. Of course, we can do that on top of this series - unifying both implementations. -- Thanks, David / dhildenb