From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3896EC2D0B1 for ; Thu, 6 Feb 2020 15:25:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0E27722464 for ; Thu, 6 Feb 2020 15:25:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="b2d4PRk6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727999AbgBFPZF (ORCPT ); Thu, 6 Feb 2020 10:25:05 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:39077 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727557AbgBFPY1 (ORCPT ); Thu, 6 Feb 2020 10:24:27 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1581002666; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc; bh=aPgiA1OtmGuRouwsyuC9sSRrGiRoJxoCsokGWtKftGY=; b=b2d4PRk61ErQEbxNDtmMyoVOu7wM6Cc23KpHnztbCeYCpWvG+7pMnreNSaa5TiITEDFccx MxBAdta1DlqmrN9U/nYU+dYSF6Ul7BqNssP6UZDDU7jrAz7tUpvIydBJzBesDEAGcK9QiW 8IqpTRf5Otc5KvJfbYYNXv1/nJHYnXI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-218-HQSgmVpvNeq9VZ9mxPSrKw-1; Thu, 06 Feb 2020 10:24:23 -0500 X-MC-Unique: HQSgmVpvNeq9VZ9mxPSrKw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 35B7B11050D9; Thu, 6 Feb 2020 15:24:21 +0000 (UTC) Received: from llong.com (ovpn-124-223.rdu2.redhat.com [10.10.124.223]) by smtp.corp.redhat.com (Postfix) with ESMTP id 81BDD1001B05; Thu, 6 Feb 2020 15:24:17 +0000 (UTC) From: Waiman Long To: Peter Zijlstra , Ingo Molnar , Will Deacon Cc: linux-kernel@vger.kernel.org, Bart Van Assche , Waiman Long Subject: [PATCH v6 0/6] locking/lockdep: Reuse zapped chain_hlocks entries Date: Thu, 6 Feb 2020 10:24:02 -0500 Message-Id: <20200206152408.24165-1-longman@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org v6: - Drop patch 7 for now. - Incorporate further changes as suggested by PeterZ. - Increase MAX_CHAIN_BUCKETS to 16 to further minimize the possibility of having more than one chain block in bucket 0. v5: - Fix more build errors reported by kbuild test robot. v4: - Fix build errors reported by kbuild test robot. - Adopt the single chain block allocator code suggested by PeterZ which combine the last 3 patches of v3 series. - Add another patch to introduce a fast path in the chain block allocator. - In patch 1, move the inc_chains() out of CONFIG_TRACE_IRQFLAGS conditional compilation block. v3: - Move the bug fix patches to the beginning of the series. - Include a number of changes as suggested by PeterZ. - Increase MAX_CHAIN_BUCKETS from 8 to 10 to reduce the chance of using the unsized list. - Add patch 7 to add a lockdep_early_init() call. - Add patch 8 to allocate chain hlocks by splitting large chain block as a last resort. v2: - Revamp the chain_hlocks reuse patch to store the freed chain_hlocks information in the chain_hlocks entries themselves avoiding the need of a separate set of tracking structures. This, however, requires a minimum allocation size of at least 2. Thanks to PeterZ for his review and inspiring this change. - Remove the leakage counter as it is no longer applicable. - Add patch 6 to make the output of /proc/lockdep_chains more readable. It was found that when running a workload that kept on adding lock classes and then zapping them repetitively, the system will eventually run out of chain_hlocks[] entries even though there were still plenty of other lockdep data buffers available. [ 4318.443670] BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low! [ 4318.444809] turning off the locking correctness validator. In order to fix this problem, we have to make chain_hlocks[] entries reusable just like other lockdep arrays. Besides that, the patchset also adds some zapped class and chain_hlocks counters to be tracked by /proc/lockdep_stats. It also fixes leakage in the irq context counters and makes the output of /proc/lockdep_chains more readable. Waiman Long (6): locking/lockdep: Decrement irq context counters when removing lock chain locking/lockdep: Display irq_context names in /proc/lockdep_chains locking/lockdep: Track number of zapped classes locking/lockdep: Throw away all lock chains with zapped class locking/lockdep: Track number of zapped lock chains locking/lockdep: Reuse freed chain_hlocks entries kernel/locking/lockdep.c | 332 ++++++++++++++++++++++++----- kernel/locking/lockdep_internals.h | 14 +- kernel/locking/lockdep_proc.c | 31 ++- 3 files changed, 312 insertions(+), 65 deletions(-) -- 2.18.1