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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id EBBFAC3601E for ; Thu, 10 Apr 2025 09:45:07 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 376A96B0259; Thu, 10 Apr 2025 05:45:07 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 323B36B025A; Thu, 10 Apr 2025 05:45:07 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1C90A6B025B; Thu, 10 Apr 2025 05:45:07 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id F2B5B6B0259 for ; Thu, 10 Apr 2025 05:45:06 -0400 (EDT) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 8FED31C997E for ; Thu, 10 Apr 2025 09:45:06 +0000 (UTC) X-FDA: 83317650612.09.ADBF599 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf26.hostedemail.com (Postfix) with ESMTP id 423E214000F for ; Thu, 10 Apr 2025 09:45:04 +0000 (UTC) Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=ePrVvES7; dmarc=pass (policy=quarantine) header.from=redhat.com; spf=pass (imf26.hostedemail.com: domain of gshan@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=gshan@redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1744278304; h=from:from:sender: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:dkim-signature; bh=6/PhODJYUOFY/4jZ292xori9GQqlmQfr9vf/eG8mtsE=; b=v/OZcS57jyd1T2YruFLOJew5R48xt3wn8Qt0/bNONQC3iL4s3hzydJzv0n15vgw5E2u4hp XUiLJ8xxjEbzSUsnq92ct1xhA+EJwP06za3Zdbg65KIQbhsyEA79yCzHSMyqlSNQvzSCzP 1npz8zpFhQRt7jTeUqEWcBAuKK5jt3U= ARC-Authentication-Results: i=1; imf26.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=ePrVvES7; dmarc=pass (policy=quarantine) header.from=redhat.com; spf=pass (imf26.hostedemail.com: domain of gshan@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=gshan@redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1744278304; a=rsa-sha256; cv=none; b=34odxWSaBDq5yott7MmqQNVvbm67SsLjU2+R88C/oc0M+MfbQg8JiRacRFwkB5ZKLAr0It Ryxwgj2o2T4nVnLXPs5V8OqfZRuTxO8Cju0Hb1LuqivqkCaCH2ivHcKMYrsJRjGtKLmg2w sBP5fSrzCvHDI+fkIsLDjhGlp56cNqk= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1744278303; 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=6/PhODJYUOFY/4jZ292xori9GQqlmQfr9vf/eG8mtsE=; b=ePrVvES72xtPuoVnopAvKG3bX5ZVEzLfVkjB7iYSaZBQtdIa7hVcCpDvjYqhDaOlZZ/kLc 4tOqlTieuPrzOkyrsUXfsd38YtdKPGUIZadYI5yJ9EAiiAyFRDs4uzIOA8tvnEfc+6cren sSz6+chqpBcAhOZMY0x+3NIUhv0kvuo= Received: from mail-pg1-f198.google.com (mail-pg1-f198.google.com [209.85.215.198]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-281-cFdwK8hRO-mNsCmWEPv9Kg-1; Thu, 10 Apr 2025 05:45:01 -0400 X-MC-Unique: cFdwK8hRO-mNsCmWEPv9Kg-1 X-Mimecast-MFC-AGG-ID: cFdwK8hRO-mNsCmWEPv9Kg_1744278301 Received: by mail-pg1-f198.google.com with SMTP id 41be03b00d2f7-af8f28f85a7so472421a12.2 for ; Thu, 10 Apr 2025 02:45:01 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1744278301; x=1744883101; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=6/PhODJYUOFY/4jZ292xori9GQqlmQfr9vf/eG8mtsE=; b=R6+sJomCtAgpLJsYoS10ZMNa+sH+Eyol8RbnUh5H8WoUNf48hg5E9NcZAE28rzzFH9 nOMNxjVM+A+DvLOqyUTmMJ5bLJQXCR+MZgUr8oJfN9GmlzGob9KLEU9GEUfQQQmELKOO nfZZHycR2GnQsNuTAI4YVeejlZlpdK0GRwJyRF5Jph3JAd36Lkuj6gdWzw5Xa86gQ+Rk W1CMWcOoETUxrLGIlo3FCLQhXZkd/8kV8GPn0W9YgHlvPX2HIW1BH6zKFC+gFKUuz/Jj FqAy26L+XoKMIcq0YotmowwlX2KnFhAulQnww16DkY8/EEGR/wtTXXIgNhrFs+zSIwBj DAwA== X-Forwarded-Encrypted: i=1; AJvYcCVI2ImAfbmb9QJyPdDslO0TIjXuD9YCe4YijH2wdJO+ApRz/ORbTAY6N6Lve2WqPYoVG9A7eLIjVw==@kvack.org X-Gm-Message-State: AOJu0YwPntPwVv5FiDq+LphVX3/wgLmgiKz3nae+PjSSll1uXVmU4Qzk wYfEs0WGGGcrmOCnXyTaE6VaF91bI6mnJSE5mnE84fCMisXt4I+B38jrk78iAVkrH1VJ9GMJpKC f44U3lRDNkeqkQoqy13jaJ1Q9Y6Kao4zrae/5jFST6xqeL8yv X-Gm-Gg: ASbGncupKw+jQ8DMjws7Ph4nqtgcSknfvMvKn8GExq7sryYcTABWNILBbKCs+A54DHd RI2XKLKdVH3k3fPSE7sz9S0Ijs6YnvtHiRzW5gLb3PqaicOnnAhXvc5QTddQjtQJWRvq99Fbign zcwxFgUPnuOs4I2Rx0PDyDtzAtp9EtORy1Fdsx6LcHILOoBiBekh2pI+rXX4MNdVuhgTF8RwgJQ joWGO0rTgZWaMiyxJ9xFHO+9/j5z8C8uEYUVPxgGU19Im2uf1fII07J8nXCmHCAv0SY36xUdyZi Zt7ORSuRWlnb X-Received: by 2002:a17:902:f542:b0:224:e0f:4b5 with SMTP id d9443c01a7336-22b2edab992mr22561915ad.7.1744278300857; Thu, 10 Apr 2025 02:45:00 -0700 (PDT) X-Google-Smtp-Source: AGHT+IFRlBAGOXJTHImC/d9zbZzfMKPBHx1mRPlLAVbrk95GhmWW/h8KqdRrNOXYYBIBbjz/7wTkAw== X-Received: by 2002:a17:902:f542:b0:224:e0f:4b5 with SMTP id d9443c01a7336-22b2edab992mr22561775ad.7.1744278300529; Thu, 10 Apr 2025 02:45:00 -0700 (PDT) Received: from [192.168.68.55] ([180.233.125.65]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-22ac7c97298sm26133415ad.138.2025.04.10.02.44.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 10 Apr 2025 02:45:00 -0700 (PDT) Message-ID: <675d6580-814f-4fae-9dc5-9470645adc07@redhat.com> Date: Thu, 10 Apr 2025 19:44:54 +1000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [REPORT] Softlockups on PowerNV with upstream To: Oscar Salvador Cc: Aditya Gupta , linux-mm@kvack.org, Andrew Morton , Danilo Krummrich , David Hildenbrand , Greg Kroah-Hartman , Mahesh J Salgaonkar , "Rafael J. Wysocki" , Sourabh Jain , linux-kernel@vger.kernel.org References: <20250409180344.477916-1-adityag@linux.ibm.com> From: Gavin Shan In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: Bpgo5cQEPaaWI-iOPSEShkTIV8afOheKKqXW01RvYY0_1744278301 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam01 X-Stat-Signature: 64jd6h55gao185nrhmy91hmsgz6pddca X-Rspam-User: X-Rspamd-Queue-Id: 423E214000F X-HE-Tag: 1744278304-109011 X-HE-Meta: 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 RYT0roXv mVH3+DvgGPi+fL69cf3eJuIW9wFyQRckMU50pjisbRgBr3C53ivyl9Qb50MX+vkpa5N9i7FB4cuSlkPiDOcU3yUwq5RW3hH0yekWE8+VylBJciL4UfIsRN8D58S2W+E68DgfYw9/Q3OeRGd3y6IAA5wo+05+HD4yspqhiXKGL5f8wZDY+20D1Q9Oxf98uAlNjixrrd7kK0Rz4yGzlU8tnyzDYqEopZ2kJzJKJw9U0hEPhe+GDmY2VajeL96xHQ/Y7W4qu2LdDlfhhbcwI9tTNBKKOW/d62oGjoXrm/ubFvFTgc0wRd2Xawh/yaenFAN09eemix3ti/v+8IQ28HEn1H21w+JWNK0m8LHnMhzNX4DA3OeAitQqt9tC3PCn0riGBuGaQ X-Bogosity: Ham, tests=bogofilter, spamicity=0.018584, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 4/10/25 6:23 PM, Oscar Salvador wrote: > On Thu, Apr 10, 2025 at 03:35:19PM +1000, Gavin Shan wrote: >> Thanks, Oscar. You're correct that the overhead is introduced by for_each_present_section_nr(). >> I already had the fix, working on IBM's Power9 machine, where the issue can be >> reproduced. Please see the attached patch. >> >> I'm having most tests on ARM64 machine for the fix. > > Looks good to me. > But we need a comment explaining why block_id is set to ULONG_MAX > at the beginning as this might not be obvious. > > Also, do we need > if (block_id != ULONG_MAX && memory_block_id(nr) == block_id) ? > > Cannot just be > > if (memory_block_id(nr) == block_id) ? > > AFAICS, the first time we loop through 'memory_block_id(nr) == ULONG_MAX' > will evaluate false and and we will set block_id afterwards. > > Either way looks fine to me. > Another way I guess would be: > Yeah, we need to record the last handled block ID by @block_id. For the first time to register the block memory device in the loop, @block_id needs to be invalid (ULONG_MAX), bypassing the check of 'memory_block_id(nr) == block_id'. I will post the fix for review after Aditya confirms it works for him, with extra comment to explain why @block_id is initialized to ULONG_MAX. Aditya, please have a try when you get a chance, thanks! I verified it on Power9 machine where the issue exists and on one of my ARM64 machine. Thanks, Gavin