From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx164.postini.com [74.125.245.164]) by kanga.kvack.org (Postfix) with SMTP id 3DB1F6B0092 for ; Thu, 17 May 2012 16:13:10 -0400 (EDT) Date: Thu, 17 May 2012 16:13:04 -0400 (EDT) Message-Id: <20120517.161304.1765970628771192598.davem@davemloft.net> Subject: Re: [PATCH 12/17] netvm: Propagate page->pfmemalloc from skb_alloc_page to skb From: David Miller In-Reply-To: <1337266231-8031-13-git-send-email-mgorman@suse.de> References: <1337266231-8031-1-git-send-email-mgorman@suse.de> <1337266231-8031-13-git-send-email-mgorman@suse.de> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: mgorman@suse.de Cc: akpm@linux-foundation.org, linux-mm@kvack.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, neilb@suse.de, a.p.zijlstra@chello.nl, michaelc@cs.wisc.edu, emunson@mgebm.net From: Mel Gorman Date: Thu, 17 May 2012 15:50:26 +0100 > 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 page splitting is used, 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. > > It works by reintroducing and expanding the skb_alloc_page() API > to take an skb. If the page was allocated from pfmemalloc reserves, > it is automatically copied. If the driver allocates the page before > the skb, it should call skb_propagate_pfmemalloc() after the skb is > allocated to ensure the flag is copied properly. > > Failure to do so is not critical. The resulting driver may perform > slower if it is used for swap-over-NBD or swap-over-NFS but it should > not result in failure. > > [davem@davemloft.net: API rename and consistency] > Signed-off-by: Mel Gorman Acked-by: David S. Miller -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org