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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DA6FDC43334 for ; Thu, 14 Jul 2022 16:22:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238022AbiGNQWj (ORCPT ); Thu, 14 Jul 2022 12:22:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49306 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235646AbiGNQWc (ORCPT ); Thu, 14 Jul 2022 12:22:32 -0400 Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CF91962494 for ; Thu, 14 Jul 2022 09:22:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1657815750; x=1689351750; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=chXGxij14yz9RDImAqjuwivX5bwn03mJi+ZsjScjEuo=; b=JUkKilsJeeLrjux3WZExCCw4htLRTYZ/W2nVPSz6Q3gkX3oiMnXc8hRr /qUs9ueYzORxOHycdDxD8DqIOG7WQQgsWpQYfmYXSg71j+laLVtpvVP1Z B8vCT/KmmRiUUC7s3SbwDPXC8LfKOLhp+FubZ0yPK7tS6GOmxxz9zcMn0 m90xXZxqvawRKfAYps4rHRKhFeDz7cAwS7abGtbYs088u4wr5GK6JIOVL 8oOPqQGA85yA+Ze0WTc0JrjOV5Alr4m5H62F3S1gakwos3INjL+ewIf6D 0w/NEAgZybon0HLQjkzg0WhrGrMV6T5i4ICP+T8PTCxEfvDxN58gFdjSd Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10408"; a="283119225" X-IronPort-AV: E=Sophos;i="5.92,271,1650956400"; d="scan'208";a="283119225" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Jul 2022 09:22:30 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.92,271,1650956400"; d="scan'208";a="593424634" Received: from lkp-server01.sh.intel.com (HELO fd2c14d642b4) ([10.239.97.150]) by orsmga007.jf.intel.com with ESMTP; 14 Jul 2022 09:22:27 -0700 Received: from kbuild by fd2c14d642b4 with local (Exim 4.95) (envelope-from ) id 1oC1be-0000rA-NX; Thu, 14 Jul 2022 16:22:26 +0000 Date: Fri, 15 Jul 2022 00:21:30 +0800 From: kernel test robot To: Nicholas Piggin Cc: llvm@lists.linux.dev, kbuild-all@lists.01.org, Nicholas Piggin , Ingo Molnar , Will Deacon , Waiman Long , Boqun Feng , "linux-kernel @ vger . kernel . org" Subject: Re: [PATCH v2 07/12] locking/qspinlock: remove arch qspinlock_paravirt.h includes Message-ID: <202207150003.29YhgBtE-lkp@intel.com> References: <20220713070704.308394-8-npiggin@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220713070704.308394-8-npiggin@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Nicholas, I love your patch! Perhaps something to improve: [auto build test WARNING on tip/locking/core] [also build test WARNING on tip/x86/core powerpc/next linus/master v5.19-rc6 next-20220714] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Nicholas-Piggin/locking-qspinlock-simplify-code-generation/20220713-151009 base: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git eae6d58d67d9739be5f7ae2dbead1d0ef6528243 config: i386-randconfig-a004 (https://download.01.org/0day-ci/archive/20220715/202207150003.29YhgBtE-lkp@intel.com/config) compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 5e61b9c556267086ef9b743a0b57df302eef831b) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://github.com/intel-lab-lkp/linux/commit/87679eeea9f1939c252d16df3ac6a01bf9daaa60 git remote add linux-review https://github.com/intel-lab-lkp/linux git fetch --no-tags linux-review Nicholas-Piggin/locking-qspinlock-simplify-code-generation/20220713-151009 git checkout 87679eeea9f1939c252d16df3ac6a01bf9daaa60 # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash kernel/locking/ If you fix the issue, kindly add following tag where applicable Reported-by: kernel test robot All warnings (new ones prefixed by >>): In file included from kernel/locking/qspinlock.c:29: kernel/locking/qspinlock_stat.h:36:9: warning: no previous prototype for function 'lockevent_read' [-Wmissing-prototypes] ssize_t lockevent_read(struct file *file, char __user *user_buf, ^ kernel/locking/qspinlock_stat.h:36:1: note: declare 'static' if the function is not intended to be used outside of this translation unit ssize_t lockevent_read(struct file *file, char __user *user_buf, ^ static kernel/locking/qspinlock.c:705:1: warning: no previous prototype for function '__pv_queued_spin_unlock_slowpath' [-Wmissing-prototypes] __pv_queued_spin_unlock_slowpath(struct qspinlock *lock, u8 locked) ^ kernel/locking/qspinlock.c:704:11: note: declare 'static' if the function is not intended to be used outside of this translation unit __visible void ^ static >> kernel/locking/qspinlock.c:749:16: warning: no previous prototype for function '__pv_queued_spin_unlock' [-Wmissing-prototypes] __visible void __pv_queued_spin_unlock(struct qspinlock *lock) ^ kernel/locking/qspinlock.c:749:11: note: declare 'static' if the function is not intended to be used outside of this translation unit __visible void __pv_queued_spin_unlock(struct qspinlock *lock) ^ static 3 warnings generated. vim +/__pv_queued_spin_unlock +749 kernel/locking/qspinlock.c 91668ee1ed703d7 Nicholas Piggin 2022-07-13 699 91668ee1ed703d7 Nicholas Piggin 2022-07-13 700 /* 91668ee1ed703d7 Nicholas Piggin 2022-07-13 701 * PV versions of the unlock fastpath and slowpath functions to be used 91668ee1ed703d7 Nicholas Piggin 2022-07-13 702 * instead of queued_spin_unlock(). 91668ee1ed703d7 Nicholas Piggin 2022-07-13 703 */ 91668ee1ed703d7 Nicholas Piggin 2022-07-13 704 __visible void 91668ee1ed703d7 Nicholas Piggin 2022-07-13 @705 __pv_queued_spin_unlock_slowpath(struct qspinlock *lock, u8 locked) 91668ee1ed703d7 Nicholas Piggin 2022-07-13 706 { 91668ee1ed703d7 Nicholas Piggin 2022-07-13 707 struct qnode *node; 91668ee1ed703d7 Nicholas Piggin 2022-07-13 708 91668ee1ed703d7 Nicholas Piggin 2022-07-13 709 if (unlikely(locked != _Q_SLOW_VAL)) { 91668ee1ed703d7 Nicholas Piggin 2022-07-13 710 WARN(!debug_locks_silent, 91668ee1ed703d7 Nicholas Piggin 2022-07-13 711 "pvqspinlock: lock 0x%lx has corrupted value 0x%x!\n", 91668ee1ed703d7 Nicholas Piggin 2022-07-13 712 (unsigned long)lock, atomic_read(&lock->val)); 91668ee1ed703d7 Nicholas Piggin 2022-07-13 713 return; 91668ee1ed703d7 Nicholas Piggin 2022-07-13 714 } 91668ee1ed703d7 Nicholas Piggin 2022-07-13 715 91668ee1ed703d7 Nicholas Piggin 2022-07-13 716 /* 91668ee1ed703d7 Nicholas Piggin 2022-07-13 717 * A failed cmpxchg doesn't provide any memory-ordering guarantees, 91668ee1ed703d7 Nicholas Piggin 2022-07-13 718 * so we need a barrier to order the read of the node data in 91668ee1ed703d7 Nicholas Piggin 2022-07-13 719 * pv_unhash *after* we've read the lock being _Q_SLOW_VAL. 91668ee1ed703d7 Nicholas Piggin 2022-07-13 720 * 91668ee1ed703d7 Nicholas Piggin 2022-07-13 721 * Matches the cmpxchg() in pv_wait_head_or_lock() setting _Q_SLOW_VAL. 91668ee1ed703d7 Nicholas Piggin 2022-07-13 722 */ 91668ee1ed703d7 Nicholas Piggin 2022-07-13 723 smp_rmb(); 91668ee1ed703d7 Nicholas Piggin 2022-07-13 724 91668ee1ed703d7 Nicholas Piggin 2022-07-13 725 /* 91668ee1ed703d7 Nicholas Piggin 2022-07-13 726 * Since the above failed to release, this must be the SLOW path. 91668ee1ed703d7 Nicholas Piggin 2022-07-13 727 * Therefore start by looking up the blocked node and unhashing it. 91668ee1ed703d7 Nicholas Piggin 2022-07-13 728 */ 91668ee1ed703d7 Nicholas Piggin 2022-07-13 729 node = pv_unhash(lock); 91668ee1ed703d7 Nicholas Piggin 2022-07-13 730 91668ee1ed703d7 Nicholas Piggin 2022-07-13 731 /* 91668ee1ed703d7 Nicholas Piggin 2022-07-13 732 * Now that we have a reference to the (likely) blocked qnode, 91668ee1ed703d7 Nicholas Piggin 2022-07-13 733 * release the lock. 91668ee1ed703d7 Nicholas Piggin 2022-07-13 734 */ 91668ee1ed703d7 Nicholas Piggin 2022-07-13 735 smp_store_release(&lock->locked, 0); 91668ee1ed703d7 Nicholas Piggin 2022-07-13 736 91668ee1ed703d7 Nicholas Piggin 2022-07-13 737 /* 91668ee1ed703d7 Nicholas Piggin 2022-07-13 738 * At this point the memory pointed at by lock can be freed/reused, 91668ee1ed703d7 Nicholas Piggin 2022-07-13 739 * however we can still use the qnode to kick the CPU. 91668ee1ed703d7 Nicholas Piggin 2022-07-13 740 * The other vCPU may not really be halted, but kicking an active 91668ee1ed703d7 Nicholas Piggin 2022-07-13 741 * vCPU is harmless other than the additional latency in completing 91668ee1ed703d7 Nicholas Piggin 2022-07-13 742 * the unlock. 91668ee1ed703d7 Nicholas Piggin 2022-07-13 743 */ 91668ee1ed703d7 Nicholas Piggin 2022-07-13 744 lockevent_inc(pv_kick_unlock); 91668ee1ed703d7 Nicholas Piggin 2022-07-13 745 pv_kick(node->cpu); 91668ee1ed703d7 Nicholas Piggin 2022-07-13 746 } 91668ee1ed703d7 Nicholas Piggin 2022-07-13 747 91668ee1ed703d7 Nicholas Piggin 2022-07-13 748 #ifndef __pv_queued_spin_unlock 91668ee1ed703d7 Nicholas Piggin 2022-07-13 @749 __visible void __pv_queued_spin_unlock(struct qspinlock *lock) 91668ee1ed703d7 Nicholas Piggin 2022-07-13 750 { 91668ee1ed703d7 Nicholas Piggin 2022-07-13 751 u8 locked; 91668ee1ed703d7 Nicholas Piggin 2022-07-13 752 91668ee1ed703d7 Nicholas Piggin 2022-07-13 753 /* 91668ee1ed703d7 Nicholas Piggin 2022-07-13 754 * We must not unlock if SLOW, because in that case we must first 91668ee1ed703d7 Nicholas Piggin 2022-07-13 755 * unhash. Otherwise it would be possible to have multiple @lock 91668ee1ed703d7 Nicholas Piggin 2022-07-13 756 * entries, which would be BAD. 91668ee1ed703d7 Nicholas Piggin 2022-07-13 757 */ 91668ee1ed703d7 Nicholas Piggin 2022-07-13 758 locked = cmpxchg_release(&lock->locked, _Q_LOCKED_VAL, 0); 91668ee1ed703d7 Nicholas Piggin 2022-07-13 759 if (likely(locked == _Q_LOCKED_VAL)) 91668ee1ed703d7 Nicholas Piggin 2022-07-13 760 return; 91668ee1ed703d7 Nicholas Piggin 2022-07-13 761 91668ee1ed703d7 Nicholas Piggin 2022-07-13 762 __pv_queued_spin_unlock_slowpath(lock, locked); 91668ee1ed703d7 Nicholas Piggin 2022-07-13 763 } 87679eeea9f1939 Nicholas Piggin 2022-07-13 764 EXPORT_SYMBOL(__pv_queued_spin_unlock); 91668ee1ed703d7 Nicholas Piggin 2022-07-13 765 #endif 91668ee1ed703d7 Nicholas Piggin 2022-07-13 766 -- 0-DAY CI Kernel Test Service https://01.org/lkp