From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <436891AE.1040709@yahoo.com.au> Date: Wed, 02 Nov 2005 21:15:10 +1100 From: Nick Piggin MIME-Version: 1.0 Subject: Re: [Lhms-devel] [PATCH 0/7] Fragmentation Avoidance V19 References: <20051030183354.22266.42795.sendpatchset@skynet.csn.ul.ie><20051031055725.GA3820@w-mikek2.ibm.com><4365BBC4.2090906@yahoo.com.au> <20051030235440.6938a0e9.akpm@osdl.org> <27700000.1130769270@[10.10.2.4]> <4366A8D1.7020507@yahoo.com.au> <4366C559.5090504@yahoo.com.au> <4366D469.2010202@yahoo.com.au> <4367D71A.1030208@austin.ibm.com> <43681100.1000603@yahoo.com.au> <214340000.1130895665@[10.10.2.4]> <43681E89.8070905@yahoo.com.au> <216280000.1130898244@[10.10.2.4]> <43682940.3020200@yahoo.com.au> <217570000.1130906356@[10.10.2.4]> <43684A16.70401@yahoo.com.au> <231260000.1130908490@[10.10.2.4]> <43685B63.7020701@jp.fujitsu.com> In-Reply-To: <43685B63.7020701@jp.fujitsu.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: KAMEZAWA Hiroyuki Cc: "Martin J. Bligh" , Joel Schopp , Mel Gorman , Andrew Morton , kravetz@us.ibm.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, lhms-devel@lists.sourceforge.net, Ingo Molnar List-ID: KAMEZAWA Hiroyuki wrote: > Martin J. Bligh wrote: > > please check kmalloc(32k,64k) > > For example, loopback device's default MTU=16436 means order=3 and > maybe there are other high MTU device. > > I suspect skb_makewritable()/skb_copy()/skb_linearize() function can be > sufferd from fragmentation when MTU is big. They allocs large skb by > gathering fragmented skbs.When these skb_* funcs failed, the packet > is silently discarded by netfilter. If fragmentation is heavy, packets > (especialy TCP) uses large MTU never reachs its end, even if loopback. > > Honestly, I'm not familiar with network code, could anyone comment this ? > I'd be interested to know, actually. I was hoping loopback should always use order-0 allocations, because the loopback driver is SG, FRAGLIST, and HIGHDMA capable. However I'm likewise not familiar with network code. -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com -- 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/ . Don't email: email@kvack.org