From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f172.google.com (mail-pf0-f172.google.com [209.85.192.172]) by kanga.kvack.org (Postfix) with ESMTP id AB88E6B0005 for ; Mon, 11 Apr 2016 12:53:57 -0400 (EDT) Received: by mail-pf0-f172.google.com with SMTP id c20so127112022pfc.1 for ; Mon, 11 Apr 2016 09:53:57 -0700 (PDT) Received: from mail-pa0-x22d.google.com (mail-pa0-x22d.google.com. [2607:f8b0:400e:c03::22d]) by mx.google.com with ESMTPS id i5si4402994pfj.121.2016.04.11.09.53.56 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 11 Apr 2016 09:53:56 -0700 (PDT) Received: by mail-pa0-x22d.google.com with SMTP id bx7so108427138pad.3 for ; Mon, 11 Apr 2016 09:53:56 -0700 (PDT) Message-ID: <1460393634.6473.560.camel@edumazet-glaptop3.roam.corp.google.com> Subject: Re: [Lsf] [Lsf-pc] [LSF/MM TOPIC] Generic page-pool recycle facility? From: Eric Dumazet Date: Mon, 11 Apr 2016 09:53:54 -0700 In-Reply-To: <20160411181907.15fdb8b9@redhat.com> References: <1460034425.20949.7.camel@HansenPartnership.com> <20160407161715.52635cac@redhat.com> <20160411085819.GE21128@suse.de> <20160411142639.1c5e520b@redhat.com> <20160411130826.GB32073@techsingularity.net> <20160411181907.15fdb8b9@redhat.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Jesper Dangaard Brouer Cc: Mel Gorman , James Bottomley , "netdev@vger.kernel.org" , Brenden Blanco , lsf@lists.linux-foundation.org, linux-mm , Mel Gorman , Tom Herbert , lsf-pc@lists.linux-foundation.org, Alexei Starovoitov On Mon, 2016-04-11 at 18:19 +0200, Jesper Dangaard Brouer wrote: > Drivers also do tricks where they fallback to smaller order pages. E.g. > lookup function mlx4_alloc_pages(). I've tried to simulate that > function here: > https://github.com/netoptimizer/prototype-kernel/blob/91d323fc53/kernel/mm/bench/page_bench01.c#L69 We use order-0 pages on mlx4 at Google, as order-3 pages are very dangerous for some kind of attacks... An out of order TCP packet can hold an order-3 pages, while claiming to use 1.5 KBvia skb->truesize. order-0 only pages allow the page recycle trick used by Intel driver, and we hardly see any page allocations in typical workloads. While order-3 pages are 'nice' for friendly datacenter kind of traffic, they also are a higher risk on hosts connected to the wild Internet. Maybe I should upstream this patch ;) -- 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