Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030475AbbD1Pv6 (ORCPT ); Tue, 28 Apr 2015 11:51:58 -0400 Received: from e7.ny.us.ibm.com ([32.97.182.137]:46313 "EHLO e7.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030232AbbD1Pvx (ORCPT ); Tue, 28 Apr 2015 11:51:53 -0400 From: "Shreyas B. Prabhu" To: linux-kernel@vger.kernel.org Cc: rostedt@goodmis.org, mingo@redhat.com, aneesh.kumar@linux.vnet.ibm.com, "Shreyas B. Prabhu" Subject: [PATCH 3/3] tracing/mm: Don't trace mm_page_pcpu_drain on offline cpus Date: Tue, 28 Apr 2015 21:21:23 +0530 Message-Id: <1430236283-29360-3-git-send-email-shreyas@linux.vnet.ibm.com> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1430236283-29360-1-git-send-email-shreyas@linux.vnet.ibm.com> References: <1430236283-29360-1-git-send-email-shreyas@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15042815-0037-0000-0000-0000011ECBEE Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3110 Lines: 82 Since tracepoints use RCU for protection, they must not be called on offline cpus. trace_mm_page_pcpu_drain can be called on an offline cpu in this scenario caught by LOCKDEP: =============================== [ INFO: suspicious RCU usage. ] 4.1.0-rc1+ #9 Not tainted ------------------------------- include/trace/events/kmem.h:265 suspicious rcu_dereference_check() usage! other info that might help us debug this: RCU used illegally from offline CPU! rcu_scheduler_active = 1, debug_locks = 1 1 lock held by swapper/5/0: #0: (&(&zone->lock)->rlock){..-...}, at: [] .free_pcppages_bulk+0x70/0x920 stack backtrace: CPU: 5 PID: 0 Comm: swapper/5 Not tainted 4.1.0-rc1+ #9 Call Trace: [c000001fed2e7720] [c0000000009dee8c] .dump_stack+0x98/0xd4 (unreliable) [c000001fed2e77a0] [c000000000128d88] .lockdep_rcu_suspicious+0x108/0x170 [c000001fed2e7830] [c00000000020794c] .free_pcppages_bulk+0x60c/0x920 [c000001fed2e7980] [c000000000208188] .free_hot_cold_page+0x208/0x280 [c000001fed2e7a30] [c00000000004d000] .destroy_context+0x90/0xd0 [c000001fed2e7ab0] [c0000000000bd1d8] .__mmdrop+0x58/0x160 [c000001fed2e7b40] [c0000000001068e0] .idle_task_exit+0xf0/0x100 [c000001fed2e7bc0] [c000000000066948] .pnv_smp_cpu_kill_self+0x58/0x2c0 [c000001fed2e7ca0] [c00000000003ce34] .cpu_die+0x34/0x50 [c000001fed2e7d10] [c0000000000176d0] .arch_cpu_idle_dead+0x20/0x40 [c000001fed2e7d80] [c00000000011f9a8] .cpu_startup_entry+0x708/0x7a0 [c000001fed2e7ec0] [c00000000003cb6c] .start_secondary+0x36c/0x3a0 [c000001fed2e7f90] [c000000000008b6c] start_secondary_prolog+0x10/0x14 Fix this by converting mm_page_pcpu_drain trace point into TRACE_EVENT_CONDITION where condition is cpu_online(smp_processor_id()) Signed-off-by: Shreyas B. Prabhu --- include/trace/events/kmem.h | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/include/trace/events/kmem.h b/include/trace/events/kmem.h index 4abda92..6cd975f 100644 --- a/include/trace/events/kmem.h +++ b/include/trace/events/kmem.h @@ -257,12 +257,26 @@ DEFINE_EVENT(mm_page, mm_page_alloc_zone_locked, TP_ARGS(page, order, migratetype) ); -DEFINE_EVENT_PRINT(mm_page, mm_page_pcpu_drain, +TRACE_EVENT_CONDITION(mm_page_pcpu_drain, TP_PROTO(struct page *page, unsigned int order, int migratetype), TP_ARGS(page, order, migratetype), + TP_CONDITION(cpu_online(smp_processor_id())), + + TP_STRUCT__entry( + __field( unsigned long, pfn ) + __field( unsigned int, order ) + __field( int, migratetype ) + ), + + TP_fast_assign( + __entry->pfn = page ? page_to_pfn(page) : -1UL; + __entry->order = order; + __entry->migratetype = migratetype; + ), + TP_printk("page=%p pfn=%lu order=%d migratetype=%d", pfn_to_page(__entry->pfn), __entry->pfn, __entry->order, __entry->migratetype) -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/