From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.11]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CD96B3E49F7; Fri, 11 Sep 2026 02:41:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.11 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789094482; cv=none; b=aBBwxplrVF277BQ95qYAuo960AtY02BqkpSqs+UtMlJtWFL9eR/wnlJOd0NoQtKA0K37CpEb9s3FhxCFGmEUWTfrb4SNCmn8vOCqELSnxBKWwE0TPN3UiE9jYGja7z5afH0x6vtJJPjDT9tiy1eFJqiGfbgksSrblSICXvDptic= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789094482; c=relaxed/simple; bh=RpS5lxvIqvCnyCF5vcYKjHed80SBUp0dNIQ0rgcc1dA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qwUzrvYodzVz18MXyx6BpbmJWmDNDMwINgyKB3CUDWSJ1nJKoSHsdlIin0uRTUL8U9EAg2gbhCM0N7pFmAqZbH71I6cjp6R7cJjxaLPBusZA4WVlZLEddjiTrLFwVhywNqu4KxYvXyCTMxLewMYgU5bolwwzn8qEK7e4cP2JEfY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=UCKEos94; arc=none smtp.client-ip=192.198.163.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="UCKEos94" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1789094480; x=1820630480; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=RpS5lxvIqvCnyCF5vcYKjHed80SBUp0dNIQ0rgcc1dA=; b=UCKEos941qLkpNqeWgl+CqusfmwF2r5xi8uWJAROBeUW1d8P7Lf4G60I 9rdBU9BiB1VN9BVEbx9LXUGmefxMOnIjA7SIVBRJEoH/DyAggldL/1cf+ 7WAYD6XNW05kgKAQe9+TXxDKkbgKt/UD3Ls8c3QDEpjGq3GpLB2N74wZJ TLfCyYU1a/vujsWOnKV4QBo2GYLAS6iHF3JTc6KJqnw5SKQjaAOcP39xj shBiv2068PYHO47t4oKCkrYCrWVxqSq3gi2yGuS+6gw9GS1KK3GSY1fXZ G/8wbOdbluU5uFaOxvFEb1cLc8A9eDDkduCkG2Fd+JdnNoMQ4DLrsCY6c A==; X-CSE-ConnectionGUID: wSUQV0fETmmT20vYLT0yyg== X-CSE-MsgGUID: XtQgg8DiRCm+WPQNFffUkw== X-IronPort-AV: E=McAfee;i="6800,10657,11901"; a="100151354" X-IronPort-AV: E=Sophos;i="6.27,96,1787036400"; d="scan'208";a="100151354" Received: from orviesa008.jf.intel.com ([10.64.159.148]) by fmvoesa105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Sep 2026 19:41:19 -0700 X-CSE-ConnectionGUID: y/s/pk7YS2a6KV1g9cJQuQ== X-CSE-MsgGUID: nvZFIjuyTc+nSfkolQcyTA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.27,96,1787036400"; d="scan'208";a="271326838" Received: from pankris-x299-ud4-pro.bj.intel.com ([10.238.152.122]) by orviesa008.jf.intel.com with ESMTP; 10 Sep 2026 19:41:16 -0700 From: Kris Pan To: edumazet@google.com Cc: davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, atomasov@redhat.com, oliver.sang@intel.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Kris Pan Subject: [PATCH v2] net: iterate online nodes in skb_defer_free_flush() Date: Fri, 11 Sep 2026 10:38:04 +0800 Message-ID: <20260911023804.3503989-1-kris.pan@intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260911020438.3502801-1-kris.pan@intel.com> References: <20260911020438.3502801-1-kris.pan@intel.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit skb_attempt_defer_free() only queues skbs on the current CPU's node (numa_node_id() of a running CPU), which is always online, so the flush loop never needs to visit nodes that are merely possible. for_each_node() walks node_possible_map. On machines where the possible map is much larger than the online map -- e.g. a POWER10 LPAR with 32 possible but 1 online node -- the flush loop touches 31 cold, always-empty per-node lists on every softirq pass, showing up as skb_defer_free_flush() and _find_next_bit() overhead. Use for_each_online_node() to iterate only node_online_map. Loopback UDP throughput in a QEMU guest with 32 possible / 1 online nodes (bench_udp, 8 senders, 6 interleaved runs) improves by ~5%. Fixes: 5628f3fe3b16 ("net: add NUMA awareness to skb_attempt_defer_free()") Reported-by: kernel test robot Suggested-by: Adrian Tomasov Closes: https://lore.kernel.org/oe-lkp/202512112119.5b9829a-lkp@intel.com Signed-off-by: Kris Pan Reviewed-by: Eric Dumazet --- net/core/dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/dev.c b/net/core/dev.c index 290e0f099e6bf..b528b6a986fcf 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6907,7 +6907,7 @@ static void skb_defer_free_flush(void) struct skb_defer_node *sdn; int node; - for_each_node(node) { + for_each_online_node(node) { sdn = this_cpu_ptr(net_hotdata.skb_defer_nodes) + node; if (llist_empty(&sdn->defer_list)) -- 2.43.0