From patchwork Fri Jun 29 13:32:41 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mel Gorman X-Patchwork-Id: 168099 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 683D6B6EEB for ; Fri, 29 Jun 2012 23:41:47 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932218Ab2F2NlZ (ORCPT ); Fri, 29 Jun 2012 09:41:25 -0400 Received: from cantor2.suse.de ([195.135.220.15]:45476 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932124Ab2F2NdC (ORCPT ); Fri, 29 Jun 2012 09:33:02 -0400 Received: from relay2.suse.de (unknown [195.135.220.254]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx2.suse.de (Postfix) with ESMTP id BCE4DA4CAC; Fri, 29 Jun 2012 15:33:01 +0200 (CEST) From: Mel Gorman To: Andrew Morton Cc: Linux-MM , Linux-Netdev , LKML , David Miller , Neil Brown , Peter Zijlstra , Mike Christie , Eric B Munson , Eric Dumazet , Sebastian Andrzej Siewior , Mel Gorman Subject: [PATCH 10/16] netvm: Propagate page->pfmemalloc to skb Date: Fri, 29 Jun 2012 14:32:41 +0100 Message-Id: <1340976767-5737-11-git-send-email-mgorman@suse.de> X-Mailer: git-send-email 1.7.9.2 In-Reply-To: <1340976767-5737-1-git-send-email-mgorman@suse.de> References: <1340976767-5737-1-git-send-email-mgorman@suse.de> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The skb->pfmemalloc flag gets set to true iff during the slab allocation of data in __alloc_skb that the the PFMEMALLOC reserves were used. If the packet is fragmented, it is possible that pages will be allocated from the PFMEMALLOC reserve without propagating this information to the skb. This patch propagates page->pfmemalloc from pages allocated for fragments to the skb. Signed-off-by: Mel Gorman Acked-by: David S. Miller --- include/linux/skbuff.h | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 0336f02..b814bb8 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1247,6 +1247,17 @@ static inline void __skb_fill_page_desc(struct sk_buff *skb, int i, { skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; + /* + * Propagate page->pfmemalloc to the skb if we can. The problem is + * that not all callers have unique ownership of the page. If + * pfmemalloc is set, we check the mapping as a mapping implies + * page->index is set (index and pfmemalloc share space). + * If it's a valid mapping, we cannot use page->pfmemalloc but we + * do not lose pfmemalloc information as the pages would not be + * allocated using __GFP_MEMALLOC. + */ + if (page->pfmemalloc && !page->mapping) + skb->pfmemalloc = true; frag->page.p = page; frag->page_offset = off; skb_frag_size_set(frag, size);