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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 41B99C4167B for ; Tue, 28 Nov 2023 17:18:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=BNZWZ2cbGRKiPjRi4md1HjNsFNODdVleXouDOVo/Q90=; b=DM4pWn266r23Wt 0w/r0m6YiwaPfsXWPBmW0aZ0UN7ABY58EuDy3+cHkOxFPl0oftkRRQRaes5XyhKX7t4gSb5/mh3rD /P4USCS9vculpb44VLk7h2xgQp8ZCkv7MYDxFKbcTmyvL3ILldMnBww7AgjsFNEw4g3ilMEzS0S34 vACNCRfErK1+P3M/7/dVp7cVHuyi1Bi7ksbMng4FIeSXqTgEe+R2kcYL+Qtvw6XCcIZtUVu58TBgS GvTkqt84oisqUGRmxkRLYi8ZXHSl15YfGlvY2aa/PA3D3UBiFRVpOnXu6g796GqbeH18cR4eRTOUl tpXHz4lB1erfLWd1dw0g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1r81iu-005uYo-2H; Tue, 28 Nov 2023 17:18:12 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1r81ir-005uXc-2h for linux-arm-kernel@lists.infradead.org; Tue, 28 Nov 2023 17:18:11 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9871BC15; Tue, 28 Nov 2023 09:18:54 -0800 (PST) Received: from raptor (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4C82A3F6C4; Tue, 28 Nov 2023 09:18:02 -0800 (PST) Date: Tue, 28 Nov 2023 17:17:59 +0000 From: Alexandru Elisei To: David Hildenbrand Cc: catalin.marinas@arm.com, will@kernel.org, oliver.upton@linux.dev, maz@kernel.org, james.morse@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, arnd@arndb.de, akpm@linux-foundation.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, mhiramat@kernel.org, rppt@kernel.org, hughd@google.com, pcc@google.com, steven.price@arm.com, anshuman.khandual@arm.com, vincenzo.frascino@arm.com, eugenis@google.com, kcc@google.com, hyesoo.yu@samsung.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org Subject: Re: [PATCH RFC v2 06/27] mm: page_alloc: Allow an arch to hook early into free_pages_prepare() Message-ID: References: <20231119165721.9849-1-alexandru.elisei@arm.com> <20231119165721.9849-7-alexandru.elisei@arm.com> <45466b05-d620-41e5-8a2b-05c420b8fa7b@redhat.com> <2e2d3f51-34e3-4982-b982-ab7b555cba21@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <2e2d3f51-34e3-4982-b982-ab7b555cba21@redhat.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231128_091809_923222_428D82D2 X-CRM114-Status: GOOD ( 27.05 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi, On Tue, Nov 28, 2023 at 05:58:55PM +0100, David Hildenbrand wrote: > On 27.11.23 14:03, Alexandru Elisei wrote: > > Hi, > > > > On Fri, Nov 24, 2023 at 08:36:52PM +0100, David Hildenbrand wrote: > > > On 19.11.23 17:57, Alexandru Elisei wrote: > > > > Add arch_free_pages_prepare() hook that is called before that page flags > > > > are cleared. This will be used by arm64 when explicit management of tag > > > > storage pages is enabled. > > > > > > Can you elaborate a bit what exactly will be done by that code with that > > > information? > > > > Of course. > > > > The MTE code that is in the kernel today uses the PG_arch_2 page flag, which it > > renames to PG_mte_tagged, to track if a page has been mapped with tagging > > enabled. That flag is cleared by free_pages_prepare() when it does: > > > > page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; > > > > When tag storage management is enabled, tag storage is reserved for a page if > > and only if the page is mapped as tagged. When a page is freed, the code looks > > at the PG_mte_tagged flag to determine if the page was mapped as tagged, and > > therefore has tag storage reserved, to determine if the corresponding tag > > storage should also be freed. > > > > I have considered using arch_free_page(), but free_pages_prepare() calls the > > function after the flags are cleared. > > > > Does that answer your question? > > Yes, please add some of that to the patch description! Will do! Thanks, Alex > > -- > Cheers, > > David / dhildenb > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel