Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933005AbcCHQkG (ORCPT ); Tue, 8 Mar 2016 11:40:06 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:22198 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753635AbcCHQj6 (ORCPT ); Tue, 8 Mar 2016 11:39:58 -0500 Subject: Re: [PATCH v2 net-next 0/12] bpf: map pre-alloc To: Daniel Wagner , "David S . Miller" References: <1457416641-306326-1-git-send-email-ast@fb.com> <56DE97A8.1050309@bmw-carit.de> CC: Daniel Borkmann , Tom Zanussi , Wang Nan , He Kuang , Martin KaFai Lau , Brendan Gregg , , , From: Alexei Starovoitov Message-ID: <56DF001D.4000002@fb.com> Date: Tue, 8 Mar 2016 08:38:53 -0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <56DE97A8.1050309@bmw-carit.de> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [192.168.52.123] X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-03-08_06:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 559 Lines: 11 On 3/8/16 1:13 AM, Daniel Wagner wrote: >> Some time back Daniel Wagner reported crashes when bpf hash map is >> >used to compute time intervals between preempt_disable->preempt_enable >> >and recently Tom Zanussi reported a dead lock in iovisor/bcc/funccount >> >tool if it's used to count the number of invocations of kernel >> >'*spin*' functions. Both problems are due to the recursive use of >> >slub and can only be solved by pre-allocating all map elements. > > I gave it a short spin and lathist sample works just fine. awesome. Thanks for testing!