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 CADF3C44508 for ; Wed, 21 Jan 2026 20:41:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:References:Cc:To:Subject:MIME-Version:Date: Message-ID:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=djpJyuMScmlBrHd91p9Wz9+Dh8n8NY06xyptDyrXdV4=; b=wJOGF28Q+V/3XfdgUoQ8IKK+h9 7JGRLeDDJxeh1juDezb1wMyISmisAMC4G/w3w8sdGQOnopQpxaJrZ6y31W/Cg7Z0HHspcwNY8UUap A7kHQhsblDFJTfA0KN6YvcVq3qUkTehsnWg9LNbJLrFFTb0to+OXb7TblCBlcg146sR1oOXbia30+ TzBazzN83rPuJuI6xzpElgqaSzChrNB0g9CFAwpnKQx3MtrzepdylmPCY/3L/SSjn7U1PWju8jxhJ eJ9rjWE9lk33m/XKs4toD1d3VWt/UCRnQC/vh0A6UBzvX4hWqBfcSyk794GbCZ3oamgrrMwVFZIfN BqaShUvw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vif18-000000062X3-0qcD; Wed, 21 Jan 2026 20:41:30 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vif15-000000062WE-300P for linux-arm-kernel@lists.infradead.org; Wed, 21 Jan 2026 20:41:29 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1769028086; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=djpJyuMScmlBrHd91p9Wz9+Dh8n8NY06xyptDyrXdV4=; b=gqdTkXQlgCH9keo/wHQl9NI/JLMScXjv2YMOIHdLuy/Qry48Ogoi+Kd3gM5bcUoMbyEIO4 a4D5qnUoX/ywnNUp9pzarbHHGCNewu2+5lR+Wj9x+9OwtLf16DKHPs5pi10XRYSZp9degv 3XkBu4fYJgAvSTREA3s8fYr832NgKg8= Received: from mail-qk1-f197.google.com (mail-qk1-f197.google.com [209.85.222.197]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-16-qrrxNNqnOEyD-uk0_BD3QQ-1; Wed, 21 Jan 2026 15:41:25 -0500 X-MC-Unique: qrrxNNqnOEyD-uk0_BD3QQ-1 X-Mimecast-MFC-AGG-ID: qrrxNNqnOEyD-uk0_BD3QQ_1769028082 Received: by mail-qk1-f197.google.com with SMTP id af79cd13be357-8ba026720eeso79318185a.1 for ; Wed, 21 Jan 2026 12:41:22 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769028082; x=1769632882; h=content-transfer-encoding:in-reply-to:content-language:references :cc:to:subject:user-agent:mime-version:date:message-id:from:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=djpJyuMScmlBrHd91p9Wz9+Dh8n8NY06xyptDyrXdV4=; b=PuwvF8rL34xb9xyuOllzIoPv0yp8SGGSRYDbSEUApqEWS0DOt/iD/Wi6xTEri+nDNS ZD7E/zfvEucvC1L0BF+LVL195fJG/kVIxB/+ecfPSbdmZwWiEv9zASxbFYgF4dma7Epl rfRIn9u5gUpQdmWn1E4wxeJ6TpkwZ9xwvUVRdcepzYYJZjye5ROExZUyR6QJNOD3q9oL AZYhIlBm722OO/43e58YvdPZVVRjlV1JUd4SNX/hcoBJYQwWQxbDPSDfBgGP6k2lj+Ay ou2wYSUYu745smCZL9kXhtPF+UZTlZrAROiEqr4+prry2erBZ8+fBOGFUbQpxImVEyQb fG+Q== X-Forwarded-Encrypted: i=1; AJvYcCUyRE4mB5ODsw8vtVjh8B5WfiIpv4EfXelPY90mJDR0wUMxh0l36pvgz9xPN8gkiIfFfm+hgdMdVpG2H+QutMgX@lists.infradead.org X-Gm-Message-State: AOJu0Yxv6u4thjUxvAAZWV+prF+UNv9UPJ7C9VB2g5eJgQjKJqJtj5d7 EcFA0WvPc0mKh+51JPyxjcL1CSSuJdHKAsOG45Q95fybZFszkC0TeQaIHbmfizKTRiv40wJ7Dbo AmsONTm7zRPwxHxLs/yRpYkDpiKw4V0aeWQGY0svftM7D7NV6ixwZViPc1rXmitqmXf4zR/PPxt rj X-Gm-Gg: AZuq6aKkIfIs7FcLBJEEgpob7mwJV7GRKYErDC89OxTuhgFig5Q0L/L06TaL9Lurhya nWqZXcX48cspipOR7NSrMrLgtQWmG8O0pU97VaFf/qVh+TsPws8wz28nKMJCCdd3cy4Low2j8C6 ilMFiUBrxnGWE9iTpbFSNKe2gWNqZA1fw9Zbxxl2UmfzfKi5bQsWexpfmqqu/W2qJdP5HKF50SI Rq61HfKTQlRyXkCxetQU8UnoodRo5rmOY7yKNTWJU7ZtfLTOH6HX7s01xtMaCNcy3aC09Iz/CZF 83Hv5XaU0Nu6xGGz3E0WRy1ZBkoC+qj0EW/HXiIGeNSLMsljAxsOW/DmJuyX7XT75NRjNXz66aC 9kTpPUAje+33Gmil2foseAFVuZHTESSc5IwLOBoRI1TVSJ3Irp4X4niXe X-Received: by 2002:a05:620a:4714:b0:8c6:a628:8608 with SMTP id af79cd13be357-8c6a66d1d82mr2524754785a.6.1769028081667; Wed, 21 Jan 2026 12:41:21 -0800 (PST) X-Received: by 2002:a05:620a:4714:b0:8c6:a628:8608 with SMTP id af79cd13be357-8c6a66d1d82mr2524752485a.6.1769028081250; Wed, 21 Jan 2026 12:41:21 -0800 (PST) Received: from ?IPV6:2601:188:c102:b180:1f8b:71d0:77b1:1f6e? ([2601:188:c102:b180:1f8b:71d0:77b1:1f6e]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8c6b22bb7cbsm1036983185a.39.2026.01.21.12.41.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 21 Jan 2026 12:41:20 -0800 (PST) From: Waiman Long X-Google-Original-From: Waiman Long Message-ID: <4dc6ab03-b2ad-4411-a49b-4513c5d592ea@redhat.com> Date: Wed, 21 Jan 2026 15:41:19 -0500 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] irqchip/gic-v3-its: Don't acquire rt_spin_lock in allocate_vpe_l1_table() To: Marc Zyngier , Thomas Gleixner Cc: Sebastian Andrzej Siewior , Clark Williams , Steven Rostedt , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev References: <20260107215353.75612-1-longman@redhat.com> <864iowmrx6.wl-maz@kernel.org> <87ms2nsqju.ffs@tglx> <86wm1qlq7l.wl-maz@kernel.org> <87ecnwij44.ffs@tglx> <86v7h8l9ht.wl-maz@kernel.org> <87pl7gglya.ffs@tglx> <86tswrkrh4.wl-maz@kernel.org> <861pjjcqdi.wl-maz@kernel.org> In-Reply-To: <861pjjcqdi.wl-maz@kernel.org> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: 1rh3xOsLUzf32fmPYKu8gaehi9Tq1uOXUwBt3BHX9ME_1769028082 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260121_124127_833115_53F85C40 X-CRM114-Status: GOOD ( 20.20 ) 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 1/21/26 3:38 AM, Marc Zyngier wrote: > On Mon, 12 Jan 2026 11:20:07 +0000, > Marc Zyngier wrote: >> On Sun, 11 Jan 2026 16:20:45 +0000, >> Thomas Gleixner wrote: >>> On Sun, Jan 11 2026 at 10:38, Marc Zyngier wrote: >>>> On Sun, 11 Jan 2026 09:39:07 +0000, >>>> Thomas Gleixner wrote: >>>>> On Fri, Jan 09 2026 at 16:13, Marc Zyngier wrote: >>>>>> On Thu, 08 Jan 2026 22:11:33 +0000, >>>>>> Thomas Gleixner wrote: >>>>>>> At the point where a CPU is brought up, the topology should be known >>>>>>> already, which means this can be allocated on the control CPU _before_ >>>>>>> the new CPU comes up, no? >>>>>> No. Each CPU finds *itself* in the forest of redistributors, and from >>>>>> there tries to find whether it has some shared resource with a CPU >>>>>> that has booted before it. That's because firmware is absolutely awful >>>>>> and can't present a consistent view of the system. >>>>> Groan.... >>>>> >>>>>> Anyway, I expect it could be solved by moving this part of the init to >>>>>> an ONLINE HP callback. >>>>> Which needs to be before CPUHP_AP_IRQ_AFFINITY_ONLINE, but even that >>>>> might be to late because there are callbacks in the STARTING section, >>>>> i.e. timer, perf, which might rely on interrupts being accessible. >>>> Nah. This stuff is only for direct injection of vLPIs into guests, so >>>> as long as this is done before we can schedule a vcpu on this physical >>>> CPU, we're good. No physical interrupt is concerned with this code. >>> That's fine then. vCPUs are considered "user-space" tasks and can't be >>> scheduled before CPUHP_AP_ACTIVE sets the CPU active for the scheduler. >> Waiman, can you please give the following hack a go on your box? The >> machines I have are thankfully limited to a single ITS group, so I >> can't directly reproduce your issue. > Have you managed to try this hack? I may be able to spend some time > addressing the issue in the next cycle if I have an indication that > I'm on the right track. Yes, I have tried out your hack patch and the 2-socket Grace test system booted up without producing any bug report for a RT debug kernel. I will try out your official patch once it come out. So moving the memory allocation to a later part of the hotplug bringup pipeline where sleeping is allowed should work. Cheers, Longman