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[209.132.180.67]) by mx.google.com with ESMTP id a9si7870927pgt.415.2019.03.17.23.59.19; Sun, 17 Mar 2019 23:59:34 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=sm70s1yn; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727889AbfCRG4e (ORCPT + 99 others); Mon, 18 Mar 2019 02:56:34 -0400 Received: from mail-lf1-f67.google.com ([209.85.167.67]:44460 "EHLO mail-lf1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727769AbfCRG4d (ORCPT ); Mon, 18 Mar 2019 02:56:33 -0400 Received: by mail-lf1-f67.google.com with SMTP id u9so10784252lfe.11 for ; Sun, 17 Mar 2019 23:56:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=tp0gV0tq+BmhiNJ7POdrMiMAn60sM6dP9Em7UwdIHuk=; b=sm70s1ynaSmZ7S7rxjwbjUCo/skRJW+Vtn8DcShgcNcVOvmxzSXUA6dTl8mFhAkFh9 DPOzfMgVbBSCZ1IJaZoYUqW5IS9BtsrjhrcwP8k/C3CH1F220vW04XnSTNMPWCcw9hCY HACO8Jmk6BJgfSTFJg0xd7eKJ6u7h074bN40aunM8ZA9CY0ew1n9bV5PcF03OdZU7Cvl bbsa1v7k/xcqW7gMSq5yqDVzbU/My0hm/mbvIS3QVL3dKs+wxQtCFlYkp7ZjSXp0WTDK E6Wk2dDqXcAmgPFIXNy3MS7Vs8a69t6Z3r0PkpZYLsDL38JpZKiq6m8YWBI0qjIeRc6/ OP3Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=tp0gV0tq+BmhiNJ7POdrMiMAn60sM6dP9Em7UwdIHuk=; b=KBnElr3QwSuoOwEbE26q+HsuCWlEyYpb037FmpSmHRcVzAHvzlGR56F/NGCVH6VkqQ eUojAcOmSvW3/eKjZylESD8QuGu+NHKG+yLZzecNgGrOLm6rpxjQi9DMmIHQYl8I4xd6 Rc462/ywc9nsW4fNf6iam8+7FaMUFzlbaV9rQXru/wuXKz5uHiAYoCRaM72JHZ2pkof6 RKuSiD+ISbwbBtMq1R0vjcRTbpKDyf1ygWhbwO2QHaPp+ur66vkVW6e6NWZzFl4h3+H3 05XclU2z0MbHFx5bit3dSk/9CD53wKn2zXubsdkM17wXBH3BIeiFABvKkiKuHP+bTZUr E9LQ== X-Gm-Message-State: APjAAAWwo4Jhh0ldXLfL98B01bi8Wo37bqxjG2v2gijeTtRGEc5V71K6 Tok5b2L2TSjNqtFxfuVnt82pL1LyC/hiqv8o5WoKoZknryE= X-Received: by 2002:a19:550d:: with SMTP id n13mr9252212lfe.26.1552892191900; Sun, 17 Mar 2019 23:56:31 -0700 (PDT) MIME-Version: 1.0 References: <20190218165620.383905466@infradead.org> <20190222124544.GY9565@techsingularity.net> <14a9adf7-9b50-1dfa-0c35-d04e976081c2@oracle.com> <19d5d492-a4c1-b3c8-cae4-da2fdfcb872b@oracle.com> In-Reply-To: From: Aubrey Li Date: Mon, 18 Mar 2019 14:56:20 +0800 Message-ID: Subject: Re: [RFC][PATCH 00/16] sched: Core scheduling To: Subhra Mazumdar , Peter Zijlstra , Tim Chen Cc: Mel Gorman , Ingo Molnar , Thomas Gleixner , Paul Turner , Linux List Kernel Mailing , Linus Torvalds , "Fr?d?ric Weisbecker" , Kees Cook , Greg Kerr Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 12, 2019 at 7:36 AM Subhra Mazumdar wrote: > > > On 3/11/19 11:34 AM, Subhra Mazumdar wrote: > > > > On 3/10/19 9:23 PM, Aubrey Li wrote: > >> On Sat, Mar 9, 2019 at 3:50 AM Subhra Mazumdar > >> wrote: > >>> expected. Most of the performance recovery happens in patch 15 which, > >>> unfortunately, is also the one that introduces the hard lockup. > >>> > >> After applied Subhra's patch, the following is triggered by enabling > >> core sched when a cgroup is > >> under heavy load. > >> > > It seems you are facing some other deadlock where printk is involved. > > Can you > > drop the last patch (patch 16 sched: Debug bits...) and try? > > > > Thanks, > > Subhra > > > Never Mind, I am seeing the same lockdep deadlock output even w/o patch > 16. Btw > the NULL fix had something missing, following works. > okay, here is another one, on my system, the boot up CPUs don't match the possible cpu map, so the not onlined CPU rq->core are not initialized, which causes NULL pointer dereference panic in online_fair_sched_group(): And here is a quick fix. ----------------------------------------------------------------------------------------------------- @@ -10488,7 +10493,8 @@ void online_fair_sched_group(struct task_group *tg) for_each_possible_cpu(i) { rq = cpu_rq(i); se = tg->se[i]; - + if (!rq->core) + continue; raw_spin_lock_irq(rq_lockp(rq)); update_rq_clock(rq); attach_entity_cfs_rq(se); Thanks, -Aubrey