From patchwork Wed May 29 22:15:18 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 1107416 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=linutronix.de Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 45DlQW6NYGz9s55 for ; Thu, 30 May 2019 08:15:31 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726668AbfE2WPb (ORCPT ); Wed, 29 May 2019 18:15:31 -0400 Received: from Chamillionaire.breakpoint.cc ([146.0.238.67]:49916 "EHLO Chamillionaire.breakpoint.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726054AbfE2WPa (ORCPT ); Wed, 29 May 2019 18:15:30 -0400 Received: from localhost ([127.0.0.1] helo=flow.W.breakpoint.cc) by Chamillionaire.breakpoint.cc with esmtp (Exim 4.89) (envelope-from ) id 1hW6r2-0008F3-R6; Thu, 30 May 2019 00:15:29 +0200 From: Sebastian Andrzej Siewior To: netdev@vger.kernel.org Cc: tglx@linutronix.de, "David S. Miller" , Sebastian Andrzej Siewior Subject: [PATCH net-next 2/7] net: Don't disable interrupts in __netdev_alloc_skb() Date: Thu, 30 May 2019 00:15:18 +0200 Message-Id: <20190529221523.22399-3-bigeasy@linutronix.de> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190529221523.22399-1-bigeasy@linutronix.de> References: <20190529221523.22399-1-bigeasy@linutronix.de> MIME-Version: 1.0 X-Breakpoint-Spam-Score: -1.0 X-Breakpoint-Spam-Level: - X-Breakpoint-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1, HEADER_FROM_DIFFERENT_DOMAINS=0.001 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org __netdev_alloc_skb() can be used from any context and is used by NAPI and non-NAPI drivers. Non-NAPI drivers use it in interrupt context and NAPI drivers use it during initial allocation (->ndo_open() or ->ndo_change_mtu()). Some NAPI drivers share the same function for the initial allocation and the allocation in their NAPI callback. The interrupts are disabled in order to ensure locked access from every context to `netdev_alloc_cache'. Let __netdev_alloc_skb() check if interrupts are disabled. If they are, use `netdev_alloc_cache'. Otherwise disable BH and use `napi_alloc_cache.page'. The IRQ check is cheaper compared to disabling & enabling interrupts and memory allocation with disabled interrupts does not work on -RT. Signed-off-by: Sebastian Andrzej Siewior --- net/core/skbuff.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 8a5ff67e14d90..7f714a1196b90 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -426,7 +426,6 @@ struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int len, gfp_t gfp_mask) { struct page_frag_cache *nc; - unsigned long flags; struct sk_buff *skb; bool pfmemalloc; void *data; @@ -447,13 +446,17 @@ struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int len, if (sk_memalloc_socks()) gfp_mask |= __GFP_MEMALLOC; - local_irq_save(flags); - - nc = this_cpu_ptr(&netdev_alloc_cache); - data = page_frag_alloc(nc, len, gfp_mask); - pfmemalloc = nc->pfmemalloc; - - local_irq_restore(flags); + if (irqs_disabled()) { + nc = this_cpu_ptr(&netdev_alloc_cache); + data = page_frag_alloc(nc, len, gfp_mask); + pfmemalloc = nc->pfmemalloc; + } else { + local_bh_disable(); + nc = this_cpu_ptr(&napi_alloc_cache.page); + data = page_frag_alloc(nc, len, gfp_mask); + pfmemalloc = nc->pfmemalloc; + local_bh_enable(); + } if (unlikely(!data)) return NULL;