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 8C72636194C; Mon, 28 Sep 2026 01:50:21 +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=1790560223; cv=none; b=Of7KFBHpB8AVyJbGS8UF9MRv56iDGozI+lmXaGPolP6OaMCZMdLPF2OR3mj+HrqX8no/xQpNoX54knZ++lKvh+ifttYokQsG/q1WXXRRarrf2aVn/JGbQedWd6PDkaHMX07WXB6MiAHM5pWSb6EnXn/Wy0BrTYRGZGoKtoeedeY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790560223; c=relaxed/simple; bh=jPF6GWwPpqMHR2e/0rkB/E1sLSmxzcdgG8z7Tdyu79k=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=gMsT+D7BZ3mo/QBtUESKfiI0XF2K6uEd3mlrb8q/MKcYytc1s9mIFc0EY2QohiU4xeY3MnTwstOwB9XqDWq7T72nQH9eOa/pHE7e/oAPMbjXMyHF+M2Sm43fck4rmqWKbOAFyz34sGuMAPUH36ONHrgLSmrZpHAtJ/gmLODEKhM= 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=e65gIvrw; 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="e65gIvrw" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1790560222; x=1822096222; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=jPF6GWwPpqMHR2e/0rkB/E1sLSmxzcdgG8z7Tdyu79k=; b=e65gIvrwgBsmwsAutUuO00GytD969nx13ALmetwVHiarCHHe9Ve/QPDp 74BBFdkbLeIHyKhetlcF4HrDMEq5DLE0YV9jfG1Diwkahgb1zhoUaU/LZ RoRvfCSUCuxVxAF5ZrRccDEQ0lLLT/0MTM83hqYQmrL2jLOpvQtWZV94V OWcjLGrlZHxubej+YY9GxFi8omxjZ/ZME7S6a/FUpOXLDtPfxtkpCujMY Xf5z2FdfKyD1i2gWtHp07+3VUJcR82Cl1pzsIg+cSD8Y2HykgVcq2TgL/ xKGRxvyTOMwIOod04OrY60gCY+2fa2/xSkj+nyu6phQCIpHljaxBggRMC g==; X-CSE-ConnectionGUID: A7FDUBCCQSqKzKgty7sTRQ== X-CSE-MsgGUID: kSGVuqNmQGKmdLcTeDiLlQ== X-IronPort-AV: E=McAfee;i="6800,10657,11918"; a="101823440" X-IronPort-AV: E=Sophos;i="6.27,127,1787036400"; d="scan'208";a="101823440" Received: from fmviesa002.fm.intel.com ([10.60.135.142]) by fmvoesa105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Sep 2026 18:50:21 -0700 X-CSE-ConnectionGUID: kaShKSaXTu+iHshTOi0MFA== X-CSE-MsgGUID: hjoB8snsSQqQVpjOxOOHnQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.27,127,1787036400"; d="scan'208";a="301187851" Received: from pankris-x299-ud4-pro.bj.intel.com ([10.238.152.122]) by fmviesa002.fm.intel.com with ESMTP; 27 Sep 2026 18:50:16 -0700 From: Kris Pan To: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com Cc: horms@kernel.org, atomasov@redhat.com, oliver.sang@intel.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Kris Pan Subject: [PATCH net-next] net: iterate online nodes in skb_defer_free_flush() Date: Mon, 28 Sep 2026 09:47:08 +0800 Message-ID: <20260928014708.3903028-1-kris.pan@intel.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@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. Use for_each_online_node() to iterate only node_online_map. Nodes that go offline are drained by dev_cpu_dead() ("net: flush skb_defer_nodes in dev_cpu_dead()"), so the flush no longer needs to visit offline nodes. Loopback UDP throughput in a QEMU guest with 32 possible / 1 online nodes (bench_udp, 8 senders, 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 --- 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 f660fccfc0dbc..807640155e649 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6927,7 +6927,7 @@ 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; __skb_defer_free_flush(sdn, 1); } -- 2.43.0