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=-0.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 A0B52C433E0 for ; Wed, 24 Jun 2020 18:36:53 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 649B02078E for ; Wed, 24 Jun 2020 18:36:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="EWFa2tyg" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 649B02078E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 032B76B002B; Wed, 24 Jun 2020 14:36:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F245B6B002D; Wed, 24 Jun 2020 14:36:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E12F76B002E; Wed, 24 Jun 2020 14:36:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0170.hostedemail.com [216.40.44.170]) by kanga.kvack.org (Postfix) with ESMTP id C95EE6B002B for ; Wed, 24 Jun 2020 14:36:52 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 896C52DFC for ; Wed, 24 Jun 2020 18:36:52 +0000 (UTC) X-FDA: 76964961864.17.flock30_570157c26e46 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin17.hostedemail.com (Postfix) with ESMTP id 682B8180D0185 for ; Wed, 24 Jun 2020 18:36:52 +0000 (UTC) X-HE-Tag: flock30_570157c26e46 X-Filterd-Recvd-Size: 3260 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf38.hostedemail.com (Postfix) with ESMTP for ; Wed, 24 Jun 2020 18:36:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=xU36C/WiUNJodzhyk8EQn6FWj5wnkbbbz+a3PgaakRo=; b=EWFa2tygln6IJibkrOIR04l1VN DFpaShPToa/lioJyeicFoPHR9h74piP9grxP7t70i3icz3UrsRveU8bdxf7Eb7sNhwQFwYWPdHHPf JynY6wE7/8oHaqVr/x9eGQsckraSkQNiFWnzRN2c7tghXgLy5wEMN7AviqSRy8Az6Jwi0ErXDHqTi l+xYOh7qNTaZJ4MfPk8hhgRD77TwK6NBR9nMT3jeonoKd2h4xJUWF/pHChpP/+1pi1E02eAeYx8f+ dAUMAyenSOB/zm7SSV1NB8OqY1JibLu9cxnSRjSlorSh8bnR5ApktJsRaYh+MOTH1UY2TIB5CuBYc GT+d6T9Q==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1joAGN-0004fD-Ag; Wed, 24 Jun 2020 18:36:47 +0000 Date: Wed, 24 Jun 2020 19:36:47 +0100 From: Matthew Wilcox To: Andrew Morton Cc: Catalin Marinas , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, Will Deacon , Dave P Martin , Vincenzo Frascino , Szabolcs Nagy , Kevin Brodsky , Andrey Konovalov , Peter Collingbourne , Steven Price Subject: Re: [PATCH v5 06/25] mm: Add PG_ARCH_2 page flag Message-ID: <20200624183647.GU21350@casper.infradead.org> References: <20200624175244.25837-1-catalin.marinas@arm.com> <20200624175244.25837-7-catalin.marinas@arm.com> <20200624113307.6165b3db2404c9d37b870a90@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200624113307.6165b3db2404c9d37b870a90@linux-foundation.org> X-Rspamd-Queue-Id: 682B8180D0185 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 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 Wed, Jun 24, 2020 at 11:33:07AM -0700, Andrew Morton wrote: > On Wed, 24 Jun 2020 18:52:25 +0100 Catalin Marinas wrote: > > > From: Steven Price > > > > For arm64 MTE support it is necessary to be able to mark pages that > > contain user space visible tags that will need to be saved/restored e.g. > > when swapped out. > > > > To support this add a new arch specific flag (PG_ARCH_2) that arch code > > can opt into using ARCH_USES_PG_ARCH_2. > > > > ... > > > > --- a/fs/proc/page.c > > +++ b/fs/proc/page.c > > @@ -217,6 +217,9 @@ u64 stable_page_flags(struct page *page) > > u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2); > > u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1); > > u |= kpf_copy_bit(k, KPF_ARCH, PG_arch_1); > > +#ifdef CONFIG_ARCH_USES_PG_ARCH_2 > > + u |= kpf_copy_bit(k, KPF_ARCH_2, PG_arch_2); > > +#endif > > Do we need CONFIG_ARCH_USES_PG_ARCH_2? What would be the downside to > giving every architecture a PG_arch_2, but only arm64 uses it (at > present)? 32-bit architectures don't have space for it. We could condition it on CONFIG_64BIT instead.