From patchwork Fri Jun 7 19:20:34 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: 1112186 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 45LC7321zJz9s7h for ; Sat, 8 Jun 2019 05:21:03 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730000AbfFGTVC (ORCPT ); Fri, 7 Jun 2019 15:21:02 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:51131 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729379AbfFGTVC (ORCPT ); Fri, 7 Jun 2019 15:21:02 -0400 Received: from localhost ([127.0.0.1] helo=flow.W.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1hZKQ5-0004YF-VL; Fri, 07 Jun 2019 21:20:58 +0200 From: Sebastian Andrzej Siewior To: netdev@vger.kernel.org Cc: tglx@linutronix.de, "David S. Miller" , Sebastian Andrzej Siewior Subject: [PATCH v2 net-next 1/7] net: Don't disable interrupts in napi_alloc_frag() Date: Fri, 7 Jun 2019 21:20:34 +0200 Message-Id: <20190607192040.19367-2-bigeasy@linutronix.de> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190607192040.19367-1-bigeasy@linutronix.de> References: <20190607192040.19367-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org netdev_alloc_frag() 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_frag() check if interrupts are disabled. If they are, use `netdev_alloc_cache' otherwise disable BH and invoke __napi_alloc_frag() for the allocation. 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 | 53 ++++++++++++++++++++++------------------------- 1 file changed, 25 insertions(+), 28 deletions(-) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 47c1aa9ee0454..e246120bdd1b4 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -365,34 +365,6 @@ struct napi_alloc_cache { static DEFINE_PER_CPU(struct page_frag_cache, netdev_alloc_cache); static DEFINE_PER_CPU(struct napi_alloc_cache, napi_alloc_cache); -static void *__netdev_alloc_frag(unsigned int fragsz, gfp_t gfp_mask) -{ - struct page_frag_cache *nc; - unsigned long flags; - void *data; - - local_irq_save(flags); - nc = this_cpu_ptr(&netdev_alloc_cache); - data = page_frag_alloc(nc, fragsz, gfp_mask); - local_irq_restore(flags); - return data; -} - -/** - * netdev_alloc_frag - allocate a page fragment - * @fragsz: fragment size - * - * Allocates a frag from a page for receive buffer. - * Uses GFP_ATOMIC allocations. - */ -void *netdev_alloc_frag(unsigned int fragsz) -{ - fragsz = SKB_DATA_ALIGN(fragsz); - - return __netdev_alloc_frag(fragsz, GFP_ATOMIC); -} -EXPORT_SYMBOL(netdev_alloc_frag); - static void *__napi_alloc_frag(unsigned int fragsz, gfp_t gfp_mask) { struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache); @@ -408,6 +380,31 @@ void *napi_alloc_frag(unsigned int fragsz) } EXPORT_SYMBOL(napi_alloc_frag); +/** + * netdev_alloc_frag - allocate a page fragment + * @fragsz: fragment size + * + * Allocates a frag from a page for receive buffer. + * Uses GFP_ATOMIC allocations. + */ +void *netdev_alloc_frag(unsigned int fragsz) +{ + struct page_frag_cache *nc; + void *data; + + fragsz = SKB_DATA_ALIGN(fragsz); + if (in_irq() || irqs_disabled()) { + nc = this_cpu_ptr(&netdev_alloc_cache); + data = page_frag_alloc(nc, fragsz, GFP_ATOMIC); + } else { + local_bh_disable(); + data = __napi_alloc_frag(fragsz, GFP_ATOMIC); + local_bh_enable(); + } + return data; +} +EXPORT_SYMBOL(netdev_alloc_frag); + /** * __netdev_alloc_skb - allocate an skbuff for rx on a specific device * @dev: network device to receive on