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 DE13DC43458 for ; Tue, 7 Jul 2026 10:31:03 +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:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From: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=1/cTRdo+GJL5Yh+CZpV8uwi7exk4QvIR8V1Wfs6Ld7M=; b=JBap1TaUq+jOfzeBSbsVUjRcAi lR+osKbg5l4pGOOqH2TMrVgBB2yuVZxcL8Ttmu8JrQez3D17aH00Kllh0z8HPgqZyJ2HIFtOnKnTv 7R6Voi5RDu+HuqQfBJRYXnwpnCjmHRGhOhhB5ig+1hU1/nDOpHzwRz7QKjyy47FLYy/r3Iaq4Wazh Gai26yehrENtpX2kKWX/ufPlpwLpuWnSSNH8i9mQr2Bvysm93U/J8uhEOXQQtuduAPOo5iq9guiUy 7oL0Iyh6IdY0E/sm0QU0UcQW8SHHFI/tnfDeLt3HJzOYcDtw/NR0pIh67nr3jk3Auks0zwHgZlWMe gSmbxTnA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wh34r-0000000EkbS-2FIK; Tue, 07 Jul 2026 10:30:57 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wh34q-0000000EkbA-2kzV for linux-arm-kernel@lists.infradead.org; Tue, 07 Jul 2026 10:30:56 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 3A6BA418C1; Tue, 7 Jul 2026 10:30:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EB2031F000E9; Tue, 7 Jul 2026 10:30:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783420256; bh=1/cTRdo+GJL5Yh+CZpV8uwi7exk4QvIR8V1Wfs6Ld7M=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=CZ4uHiVi/JIurn8joz1Hau1rp0Gu8K5SAekAw+AVegx0wrBuSzIiAQsdNCIrgwuYB kXUoBb/kfzXzMBHruIC8xrVTLeyDxLGxA0b3yy7M5D7bmwRMp0eSpLztTANkMsJ3IE rO4nlVc8vyiDDOWDrN/0CKBLmqCNrW2+2CQMYf/djbJ+gEt70DqkYjxDgVNdOtKLe+ z1Pdiorrs5b/Pqb3HINaBCCEwCsqQH6aKxgn7eTMtkDCAlDsQgV6W+igSg8iie1Jn3 KauQEtxtWLawEg2Em7sodFcHMi3ySICCAQagzhI1/CpDmTzLmABqJofChbTxLNm1s7 4ShAljprq81ug== Date: Tue, 7 Jul 2026 11:30:45 +0100 From: Will Deacon To: Jinjie Ruan Cc: catalin.marinas@arm.com, tsbogend@alpha.franken.de, tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, peterz@infradead.org, kees@kernel.org, nathan@kernel.org, linusw@kernel.org, ojeda@kernel.org, david.kaplan@amd.com, lukas.bulwahn@redhat.com, ryan.roberts@arm.com, maz@kernel.org, timothy.hayes@arm.com, lpieralisi@kernel.org, thuth@redhat.com, menglong8.dong@gmail.com, oupton@kernel.org, yeoreum.yun@arm.com, miko.lenczewski@arm.com, broonie@kernel.org, kevin.brodsky@arm.com, james.clark@linaro.org, yangyicong@hisilicon.com, tabba@google.com, osandov@fb.com, arnd@arndb.de, anshuman.khandual@arm.com, david@kernel.org, akpm@linux-foundation.org, ljs@kernel.org, dev.jain@arm.com, yang@os.amperecomputing.com, chaitanyas.prakash@arm.com, kprateek.nayak@amd.com, chenl311@chinatelecom.cn, sshegde@linux.ibm.com, thorsten.blum@linux.dev, chang.seok.bae@intel.com, tim.c.chen@linux.intel.com, x86@kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org Subject: Re: [PATCH v3 12/12] arm64: Add HOTPLUG_PARALLEL support for secondary CPUs Message-ID: References: <20260624092537.2916971-1-ruanjinjie@huawei.com> <20260624092537.2916971-13-ruanjinjie@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 Tue, Jul 07, 2026 at 12:00:12PM +0800, Jinjie Ruan wrote: > > > On 6/24/2026 5:25 PM, Jinjie Ruan wrote: > > Support for parallel secondary CPU bringup is already utilized by x86, > > MIPS and RISC-V. This patch brings this capability to the arm64 > > architecture. > > > > To fully enable HOTPLUG_PARALLEL, this patch implements an arm64-specific > > arch_cpuhp_init_parallel_bringup() handler. > > > > In parallel bringup, early `set_cpu_present(cpu, 0)` inside > > cpu_die_early() removes the secondary CPU prematurely, causing the primary > > CPU's second-stage cpuhp_bringup_mask() sweep to skip it and drop > > failure logs. > > > Hi, Will, > > In parallel bringup, cpu_die_early() calls set_cpu_present(cpu, 0), > which removes the failing secondary CPU from the mask. This causes the > primary CPU's cpuhp_bringup_mask() sweep to skip it and drop any failure > log. > > Have you seen this before, and what do you think about the fix? Yes, I tried to fix this here: https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/commit/?h=cpu-hotplug&id=7e1e4144a54a80e05017e56e0e28e759bd790daa by moving the manipulation of the present mask to arch_cpuhp_cleanup_kick_cpu(). I'd just like to nail down the RCU and cpufeature issues before posting that lot. Will