From: kernel test robot <lkp@intel.com>
To: Anatoly Stepanov <stepanov.anatoly@huawei.com>
Cc: llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev
Subject: Re: [RFC PATCH v2 3/5] kernel: introduce general hq-lock support
Date: Sun, 7 Dec 2025 23:39:58 +0800 [thread overview]
Message-ID: <202512072334.p6FnpvnH-lkp@intel.com> (raw)
In-Reply-To: <20251206062106.2109014-4-stepanov.anatoly@huawei.com>
Hi Anatoly,
[This is a private test report for your RFC patch.]
kernel test robot noticed the following build warnings:
[auto build test WARNING on tip/locking/core]
[also build test WARNING on tip/x86/core arnd-asm-generic/master v6.18]
[cannot apply to linus/master next-20251205]
[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/Anatoly-Stepanov/kernel-introduce-Hierarchical-Queued-spinlock/20251206-070428
base: tip/locking/core
patch link: https://lore.kernel.org/r/20251206062106.2109014-4-stepanov.anatoly%40huawei.com
patch subject: [RFC PATCH v2 3/5] kernel: introduce general hq-lock support
config: x86_64-allmodconfig (https://download.01.org/0day-ci/archive/20251207/202512072334.p6FnpvnH-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251207/202512072334.p6FnpvnH-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202512072334.p6FnpvnH-lkp@intel.com/
All warnings (new ones prefixed by >>):
In file included from kernel/locking/qspinlock.c:423:
>> kernel/locking/hqlock_core.h:611:17: warning: variable 'node_tail' set but not used [-Wunused-but-set-variable]
611 | u16 node_head, node_tail;
| ^
1 warning generated.
vim +/node_tail +611 kernel/locking/hqlock_core.h
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 597
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 598 static inline void handoff_remote(struct qspinlock *lock,
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 599 struct numa_qnode *qnode,
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 600 u32 tail, int handoff_info)
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 601 {
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 602 struct numa_queue *next_queue = NULL;
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 603 struct mcs_spinlock *mcs_head = NULL;
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 604 struct numa_qnode *qhead = NULL;
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 605 u16 lock_id = qnode->lock_id;
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 606
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 607 struct lock_metadata *lock_meta = get_meta(lock_id);
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 608 struct numa_queue *queue = get_local_queue(qnode);
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 609
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 610 u16 next_node_id;
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 @611 u16 node_head, node_tail;
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 612
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 613 node_tail = READ_ONCE(lock_meta->tail_node);
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 614 node_head = READ_ONCE(lock_meta->head_node);
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 615
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 616 /*
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 617 * 'handoffs_not_head > 0' means at the head of NUMA-level queue we have a node
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 618 * which is heavily loaded and has performed a remote handoff upon reaching the threshold.
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 619 *
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 620 * Perform handoff to the head instead of next node in the NUMA-level queue,
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 621 * if handoffs_not_head >= nr_online_nodes
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 622 * (It means other contended nodes have been taking the lock at least once after the head one)
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 623 */
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 624 u16 handoffs_not_head = READ_ONCE(queue->handoffs_not_head);
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 625
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 626 if (handoff_info > 0 && (handoffs_not_head < nr_online_nodes)) {
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 627 next_node_id = handoff_info;
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 628 if (node_head != qnode->numa_node)
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 629 handoffs_not_head++;
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 630 } else {
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 631 if (!node_head) {
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 632 /* If we're here - we have defintely other node-contenders, let's wait */
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 633 next_node_id = smp_cond_load_relaxed(&lock_meta->head_node, (VAL));
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 634 } else {
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 635 next_node_id = node_head;
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 636 }
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 637
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 638 handoffs_not_head = 0;
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 639 }
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 640
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 641 next_queue = get_queue(lock_id, next_node_id);
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 642 WRITE_ONCE(next_queue->handoffs_not_head, handoffs_not_head);
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 643
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 644 qhead = READ_ONCE(next_queue->head);
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 645
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 646 mcs_head = (void *) qhead;
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 647
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 648 /* arch_mcs_spin_unlock_contended implies smp-barrier */
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 649 arch_mcs_spin_unlock_contended(&mcs_head->locked);
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 650 }
1b1736c3ff9c9f Anatoly Stepanov 2025-12-06 651
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
parent reply other threads:[~2025-12-07 15:41 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <20251206062106.2109014-4-stepanov.anatoly@huawei.com>]
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