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[209.132.180.67]) by mx.google.com with ESMTP id k1si2229404oou.60.2020.04.02.06.49.48; Thu, 02 Apr 2020 06:50:01 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=xmission.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388522AbgDBNO2 (ORCPT + 99 others); Thu, 2 Apr 2020 09:14:28 -0400 Received: from out03.mta.xmission.com ([166.70.13.233]:49380 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388504AbgDBNO2 (ORCPT ); Thu, 2 Apr 2020 09:14:28 -0400 Received: from in02.mta.xmission.com ([166.70.13.52]) by out03.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jJzfp-00075I-T0; Thu, 02 Apr 2020 07:14:21 -0600 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95] helo=x220.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.87) (envelope-from ) id 1jJzfj-00021V-6R; Thu, 02 Apr 2020 07:14:21 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Linus Torvalds Cc: Jann Horn , Alan Stern , Andrea Parri , Will Deacon , Peter Zijlstra , Boqun Feng , Nicholas Piggin , David Howells , Jade Alglave , Luc Maranget , "Paul E. McKenney" , Akira Yokosawa , Daniel Lustig , Adam Zabrocki , kernel list , Kernel Hardening , Oleg Nesterov , Andy Lutomirski , Bernd Edlinger , Kees Cook , Andrew Morton , stable , Marco Elver , Dmitry Vyukov , kasan-dev References: <20200324215049.GA3710@pi3.com.pl> <202003291528.730A329@keescook> <87zhbvlyq7.fsf_-_@x220.int.ebiederm.org> Date: Thu, 02 Apr 2020 08:11:31 -0500 In-Reply-To: (Linus Torvalds's message of "Wed, 1 Apr 2020 19:05:59 -0700") Message-ID: <877dyym3r0.fsf@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1jJzfj-00021V-6R;;;mid=<877dyym3r0.fsf@x220.int.ebiederm.org>;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1/aAgD/0VF7hya1cN9dZdOTpz/w8uomdK0= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on sa01.xmission.com X-Spam-Level: X-Spam-Status: No, score=-0.2 required=8.0 tests=ALL_TRUSTED,BAYES_50, DCC_CHECK_NEGATIVE,NO_DNS_FOR_FROM,T_TM2_M_HEADER_IN_MSG autolearn=disabled version=3.4.2 X-Spam-Virus: No X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.8 BAYES_50 BODY: Bayes spam probability is 40 to 60% * [score: 0.4987] * 0.0 NO_DNS_FOR_FROM DNS: Envelope sender has no MX or A DNS records * 0.0 T_TM2_M_HEADER_IN_MSG BODY: No description available. * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa01 1397; Body=1 Fuz1=1 Fuz2=1] X-Spam-DCC: XMission; sa01 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Linus Torvalds X-Spam-Relay-Country: X-Spam-Timing: total 6259 ms - load_scoreonly_sql: 0.03 (0.0%), signal_user_changed: 4.6 (0.1%), b_tie_ro: 3.2 (0.1%), parse: 1.03 (0.0%), extract_message_metadata: 11 (0.2%), get_uri_detail_list: 0.70 (0.0%), tests_pri_-1000: 4.0 (0.1%), tests_pri_-950: 1.01 (0.0%), tests_pri_-900: 0.88 (0.0%), tests_pri_-90: 83 (1.3%), check_bayes: 82 (1.3%), b_tokenize: 5 (0.1%), b_tok_get_all: 6 (0.1%), b_comp_prob: 1.59 (0.0%), b_tok_touch_all: 66 (1.0%), b_finish: 0.79 (0.0%), tests_pri_0: 6143 (98.1%), check_dkim_signature: 0.51 (0.0%), check_dkim_adsp: 5997 (95.8%), poll_dns_idle: 5993 (95.7%), tests_pri_10: 1.70 (0.0%), tests_pri_500: 6 (0.1%), rewrite_mail: 0.00 (0.0%) Subject: Re: [PATCH] signal: Extend exec_id to 64bits X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Linus Torvalds writes: > tasklist_lock is aboue the hottest lock there is in all of the kernel. Do you know code paths you see tasklist_lock being hot? I am looking at some of the exec/signal/ptrace code paths because they get subtle corner case wrong like a threaded exec deadlocking when straced. If the performance problems are in the same neighbourhood I might be able to fix those problems while I am in the code. Eric