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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 92949C433EF for ; Wed, 13 Jul 2022 10:38:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236098AbiGMKid (ORCPT ); Wed, 13 Jul 2022 06:38:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60788 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229613AbiGMKia (ORCPT ); Wed, 13 Jul 2022 06:38:30 -0400 Received: from mailgw01.mediatek.com (unknown [60.244.123.138]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8FA40FD51C; Wed, 13 Jul 2022 03:38:22 -0700 (PDT) X-UUID: 8e25dad35ffc4f0592d46075c10dd7cb-20220713 X-CID-UNFAMILIAR: 1 X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.8,REQID:ace90e29-5bbf-4620-98e5-2e6e35d8a559,OB:0,LO B:0,IP:0,URL:0,TC:0,Content:0,EDM:0,RT:0,SF:54,FILE:0,RULE:Release_Ham,ACT ION:release,TS:54 X-CID-INFO: VERSION:1.1.8,REQID:ace90e29-5bbf-4620-98e5-2e6e35d8a559,OB:0,LOB: 0,IP:0,URL:0,TC:0,Content:0,EDM:0,RT:0,SF:54,FILE:0,RULE:Release_HamU,ACTI ON:release,TS:54 X-CID-META: VersionHash:0f94e32,CLOUDID:a60d61d7-5d6d-4eaf-a635-828a3ee48b7c,C OID:0e45bc946b18,Recheck:0,SF:28|16|19|48,TC:nil,Content:0,EDM:-3,IP:nil,U RL:1,File:nil,QS:nil,BEC:nil,COL:0 X-UUID: 8e25dad35ffc4f0592d46075c10dd7cb-20220713 Received: from mtkmbs10n1.mediatek.inc [(172.21.101.34)] by mailgw01.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 761655014; Wed, 13 Jul 2022 18:38:16 +0800 Received: from mtkcas10.mediatek.inc (172.21.101.39) by mtkmbs10n1.mediatek.inc (172.21.101.34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.2.792.15; Wed, 13 Jul 2022 18:38:14 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkcas10.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Wed, 13 Jul 2022 18:38:14 +0800 From: Lecopzer Chen To: CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: RE: [PATCH v6 0/6] Support hld delayed init based on Pseudo-NMI for arm64 Date: Wed, 13 Jul 2022 18:38:14 +0800 Message-ID: <20220713103814.16826-1-lecopzer.chen@mediatek.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20220617040740.25631-1-lecopzer.chen@mediatek.com> References: <20220617040740.25631-1-lecopzer.chen@mediatek.com> MIME-Version: 1.0 Content-Type: text/plain X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Will, Mark Sorry for another ping, but would you please help review this or comment about it? Thanks a lot. > Hi Will, Mark > > Could you help review arm parts of this patchset, please? > > For the question mention in both [1] and [2], > > > I'd still like Mark's Ack on this, as the approach you have taken doesn't > > really sit with what he was suggesting. > > > > I also don't understand how all the CPUs get initialised with your patch, > > since the PMU driver will be initialised after SMP is up and running. > > The hardlock detector utilizes the softlockup_start_all() to start all > the cpu on watchdog_allowed_mask, which will do watchdog_nmi_enable() > that registers perf event on each CPUs. > Thus we simply need to retry lockup_detector_init() in a single cpu which > will reconfig and call to softlockup_start_all(). > > Also, the CONFIG_HARDLOCKUP_DETECTOR_PERF selects SOFTLOCKUP_DETECTOR, > IMO, this shows that hardlockup detector supports from softlockup. > > > > We should know whether pNMIs are possible once we've completed > > setup_arch() (and possibly init_IRQ()), long before SMP, so so I reckon > > we should have all the information available once we get to > > lockup_detector_init(), even if that requires some preparatory rework. > > Hardlockup depends on PMU driver , I think the only way is moving > pmu driver at setup_arch() or any point which is earlier than > lockup_detector_init(), and I guess we have to reorganize the architecture > of arm PMU. > > The retry function should benifit all the arch/ not only for arm64. > Any arch who needs to probe its pmu as module can use this without providing > a chance to mess up the setup order. > > > Please let me know if you have any concern about this, thank you > > > [1] https://lore.kernel.org/all/CAFA6WYPPgUvHCpN5=EpJ2Us5h5uVWCbBA59C-YwYQX2ovyVeEw@mail.gmail.com/ > [2] https://lore.kernel.org/linux-arm-kernel/20210419170331.GB31045@willie-the-truck/ > >