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 C7AB1C3DA49 for ; Fri, 2 Aug 2024 10:41:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:MIME-Version: References:In-Reply-To:Subject:Cc:To:From:Message-ID:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=cOLwqDkM3EGuVwODfezsCmKUaHma8k+cvsJc99alV94=; b=S86ww4rE2YGNq3TsZCO9IS/IdH mh3QHEx3h8GY6xXe04KNludIoEYz8z9GZapOaP7DVIUvqH10sHJg9KR+wzg2iOKGNAy+gKD94rOPJ B3YxsEhHxNwEFXHMki7l5p7oURF6JIxct3P4dg68V2TkGmuVTRiMVKKVycyDBH6yb2bRrqy2gDkkZ KQSDcDfW78o6c2rP5e/uVks5k3t3X7zXoXSB2sHWwxSZCPq6uuN7YeR7NVlqQJQUZyZGicb9LolDX k2K6QnjxQl3HPL+PX2wdCqAGD3uAcBYJ30pGGDrKJgEvU2Dh3aUAZRQr7off79bUPwFHp8JD/fCFR 2QP+fdmA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sZpiP-00000008Vyf-3saC; Fri, 02 Aug 2024 10:40:53 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sZpht-00000008Vtm-2lA2 for linux-arm-kernel@lists.infradead.org; Fri, 02 Aug 2024 10:40:22 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id ED131627CD; Fri, 2 Aug 2024 10:40:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 96A46C32782; Fri, 2 Aug 2024 10:40:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722595220; bh=HNuIiGAaPtQQf2ddL66W+/xjIR1EwEXtVW6afYgXpSk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=dU2PVM8CPIrK0ckoHDaUFIhnr3ohoZl93VJkduYGLQEzu39HsjegcC1TpqYEYqqFu /5to928P5A5KgwLYO7B6T2uC7dveRa6RVzuQSz3aS+jbZYZ8Clc0n1e9Vb4O1CDsn9 QpBEeE/dpFRoVSnqWWx5iq4KWRwJ7XGTRV4SYwGRjFDNyLVt+jQ1if+yARwwjC+7Fh jU/a22ixRZm+Nijj9ad50TG3GQrrkQgv7+zwAvmmGNH9z5KnmNBF8gQ43IUKNY0jnJ VX023IFNtw7Ei5mcGGigEp2Z6tZeNjUuGhRfNr3hAqbiaXqVaJEzmhWpOb/mqFp3Vo bP3ih90gR0OYg== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1sZphq-0005GD-GK; Fri, 02 Aug 2024 11:40:18 +0100 Date: Fri, 02 Aug 2024 11:40:16 +0100 Message-ID: <86cymr1a3z.wl-maz@kernel.org> From: Marc Zyngier To: Yicong Yang Cc: , , , , , , , , , , , , , Subject: Re: [PATCH 0/2] Support Armv8.9/v9.4 FEAT_HAFT In-Reply-To: <20240802093458.32683-1-yangyicong@huawei.com> References: <20240802093458.32683-1-yangyicong@huawei.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/29.3 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: yangyicong@huawei.com, catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, linux-arm-kernel@lists.infradead.org, oliver.upton@linux.dev, broonie@kernel.org, ryan.roberts@arm.com, linuxarm@huawei.com, jonathan.cameron@huawei.com, shameerali.kolothum.thodi@huawei.com, prime.zeng@hisilicon.com, xuwei5@huawei.com, wangkefeng.wang@huawei.com, yangyicong@hisilicon.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240802_034021_770614_BBD9769B X-CRM114-Status: GOOD ( 16.66 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, 02 Aug 2024 10:34:56 +0100, Yicong Yang wrote: > > From: Yicong Yang > > This series adds basic support for FEAT_HAFT introduced in Armv8.9/v9.4 > and enable ARCH_HAS_NONLEAF_PMD_YOUNG. The latter will be used in > lru-gen aging. Tested with lru-gen in below steps: > 1. Generate a 1GiB workingset by `stress-ng --vm 1`. Then hang the task to > stop accessing the memory. (AF bit won't be updated) > 2. try to age the memory by /sys/kernel/debug/lru_gen > > Run above steps with LRU_GEN_NONLEAF_YOUNG(0x4) and not respectively > (switching by /sys/kernel/mm/lru_gen/enabled). LRU_GEN_NONLEAF_YOUNG > will clear and test the PMD AF bit on page walking for aging, > otherwise will clear and test the PTE AF bit for aging. In this case > LRU_GEN_NONLEAF_YOUNG will improve the efficiency of page scanning > since pages won't be accessed and we don't need to scan each PTE. Improve by how much? Can you please publish numbers that demonstrate the effect of this feature? Thanks, M. -- Without deviation from the norm, progress is not possible.