From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756309Ab2BFXDm (ORCPT ); Mon, 6 Feb 2012 18:03:42 -0500 Received: from cantor2.suse.de ([195.135.220.15]:48270 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756113Ab2BFW43 (ORCPT ); Mon, 6 Feb 2012 17:56:29 -0500 From: Mel Gorman To: Andrew Morton Cc: Linux-MM , Linux-Netdev , LKML , David Miller , Neil Brown , Peter Zijlstra , Mel Gorman Subject: [PATCH 09/15] netvm: Propagate page->pfmemalloc to skb Date: Mon, 6 Feb 2012 22:56:12 +0000 Message-Id: <1328568978-17553-10-git-send-email-mgorman@suse.de> X-Mailer: git-send-email 1.7.3.4 In-Reply-To: <1328568978-17553-1-git-send-email-mgorman@suse.de> References: <1328568978-17553-1-git-send-email-mgorman@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@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 --- include/linux/skbuff.h | 11 +++++++++++ 1 files changed, 11 insertions(+), 0 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index ca05362..17ed022 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1199,6 +1199,17 @@ 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); -- 1.7.3.4