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 4E54DCA5FD1 for ; Tue, 20 Jan 2026 17:59:42 +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:MIME-Version:Message-ID:Date:Subject:CC:To:From:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=jwrVgQu8T1zQqFt9YAueQy5DCsjrQY33U9ppp5mocfU=; b=t3Kkf4FJpuDxubFPE21vJBjj1I qYYYU1xFfq5/2EFhyKQuzwEWfP8GJSpPz6nzKgwa0wt/Xsm6WgaZwWQVRSCpLJHxPIA05Nhdosz+F OsN1hse6DTMJEWE0gF6Rjc4gZ+TNS4pQ/062AgjgjyJZMfhkpVJurm5ksnz7t5zQGfPlye7XRLYC8 C7Qf4lFQwjLtMiw836zt4gcSOIIRTmDysIo88C9Y2zdESJCxXj5OCRiKCz+TrR0fT+fjNDVA0D0Mv KCnGtrQ29mfKY/CFGCh6VexidhwRbPeJ9C/acPEx47TMGPKo7DuuWk/HL9BzwC0yqu5+6c1laO80U pvoZoFEQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1viG0q-00000004H4e-394i; Tue, 20 Jan 2026 17:59:32 +0000 Received: from pdx-out-010.esa.us-west-2.outbound.mail-perimeter.amazon.com ([52.12.53.23]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1viG0n-00000004H3p-3YVm for kexec@lists.infradead.org; Tue, 20 Jan 2026 17:59:31 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.de; i=@amazon.de; q=dns/txt; s=amazoncorp2; t=1768931969; x=1800467969; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=jwrVgQu8T1zQqFt9YAueQy5DCsjrQY33U9ppp5mocfU=; b=FT7nDKnJAOeqGaaKo/KF+1XsiU73p711t4C5btJ2O3YEHzSZxDadFYy4 nK+ufFo2ZzFGkc+bM/mHBArJA9dsYXfNFQexItm4WypigfVAIIWBOdDA0 q1+dv4/yM5IBuGCoQoYVcRj2lQua8y6UaO/9TbIOItmgiOT2IbYLjB0eV df79x0dI+SgK6AuDNTMNHRbiD9tdd7aIK/fbvgc0tkEV3jAXfzqTvTQxh qGB4DizBHS6q5QM/iMhpx2MiVWfUE+2veC/MsugJ/utdW5hGaG+URkHXO HxpeW8hIS11yjfjp9x50AHcxug15YY5oPFqu+hocGMC2sK652uNeYjpQc g==; X-CSE-ConnectionGUID: DOz3H3uJRdeGXpuxql/bYw== X-CSE-MsgGUID: h62isw/sQbqrB5itx0IYpw== X-IronPort-AV: E=Sophos;i="6.21,241,1763424000"; d="scan'208";a="11095148" Received: from ip-10-5-6-203.us-west-2.compute.internal (HELO smtpout.naws.us-west-2.prod.farcaster.email.amazon.dev) ([10.5.6.203]) by internal-pdx-out-010.esa.us-west-2.outbound.mail-perimeter.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Jan 2026 17:59:23 +0000 Received: from EX19MTAUWA001.ant.amazon.com [205.251.233.236:10556] by smtpin.naws.us-west-2.prod.farcaster.email.amazon.dev [10.0.14.244:2525] with esmtp (Farcaster) id 1f2c0798-ec03-4bf6-a1ae-8006272cbe1b; Tue, 20 Jan 2026 17:59:23 +0000 (UTC) X-Farcaster-Flow-ID: 1f2c0798-ec03-4bf6-a1ae-8006272cbe1b Received: from EX19D001UWA001.ant.amazon.com (10.13.138.214) by EX19MTAUWA001.ant.amazon.com (10.250.64.217) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.35; Tue, 20 Jan 2026 17:59:23 +0000 Received: from dev-dsk-epetron-1c-1d4d9719.eu-west-1.amazon.com (10.253.109.105) by EX19D001UWA001.ant.amazon.com (10.13.138.214) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.35; Tue, 20 Jan 2026 17:59:21 +0000 From: Evangelos Petrongonas To: Mike Rapoport CC: Evangelos Petrongonas , Pasha Tatashin , Pratyush Yadav , "Alexander Graf" , Jason Miu , , , , Subject: [PATCH v2] kho: skip memoryless NUMA nodes when reserving scratch areas Date: Tue, 20 Jan 2026 17:59:11 +0000 Message-ID: <20260120175913.34368-1-epetron@amazon.de> X-Mailer: git-send-email 2.47.3 MIME-Version: 1.0 X-Originating-IP: [10.253.109.105] X-ClientProxiedBy: EX19D036UWB002.ant.amazon.com (10.13.139.139) To EX19D001UWA001.ant.amazon.com (10.13.138.214) Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260120_095930_196958_CA0DC5D5 X-CRM114-Status: GOOD ( 12.05 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org kho_reserve_scratch() iterates over all online NUMA nodes to allocate per-node scratch memory. On systems with memoryless NUMA nodes (nodes that have CPUs but no memory), memblock_alloc_range_nid() fails because there is no memory available on that node. This causes KHO initialization to fail and kho_enable to be set to false. Some ARM64 systems have NUMA topologies where certain nodes contain only CPUs without any associated memory. These configurations are valid and should not prevent KHO from functioning. Fix this by only counting nodes that have memory (N_MEMORY state) and skip memoryless nodes in the per-node scratch allocation loop. Signed-off-by: Evangelos Petrongonas --- v2: - Removed kho_mem_nodes_count in favour of nodes_weight(nodes_state[N_MEMORY]) - Use for_each_node_state(nid, N_MEMORY) to loop over nodes that are both online and have memory. TIL: Nodes in N_MEMORY are a subset of those that are online. Thanks Mike :) kernel/liveupdate/kexec_handover.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c index 9dc51fab604f..979ebaf015bf 100644 --- a/kernel/liveupdate/kexec_handover.c +++ b/kernel/liveupdate/kexec_handover.c @@ -643,7 +643,7 @@ static void __init kho_reserve_scratch(void) scratch_size_update(); /* FIXME: deal with node hot-plug/remove */ - kho_scratch_cnt = num_online_nodes() + 2; + kho_scratch_cnt = nodes_weight(node_states[N_MEMORY]) + 2; size = kho_scratch_cnt * sizeof(*kho_scratch); kho_scratch = memblock_alloc(size, PAGE_SIZE); if (!kho_scratch) @@ -673,7 +673,11 @@ static void __init kho_reserve_scratch(void) kho_scratch[i].size = size; i++; - for_each_online_node(nid) { + /* + * Loop over nodes that have both memory and are online. Skip + * memoryless nodes, as we can not allocate scratch areas there. + */ + for_each_node_state(nid, N_MEMORY) { size = scratch_size_node(nid); addr = memblock_alloc_range_nid(size, CMA_MIN_ALIGNMENT_BYTES, 0, MEMBLOCK_ALLOC_ACCESSIBLE, -- 2.43.0 Amazon Web Services Development Center Germany GmbH Tamara-Danz-Str. 13 10243 Berlin Geschaeftsfuehrung: Christof Hellmis, Andreas Stieger Eingetragen am Amtsgericht Charlottenburg unter HRB 257764 B Sitz: Berlin Ust-ID: DE 365 538 597