Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934144AbcJZQEm (ORCPT ); Wed, 26 Oct 2016 12:04:42 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:18674 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933666AbcJZQEj (ORCPT ); Wed, 26 Oct 2016 12:04:39 -0400 From: Babu Moger To: mingo@kernel.org, akpm@linux-foundation.org, ak@linux.intel.com, jkosina@suse.cz, baiyaowei@cmss.chinamobile.com, dzickus@redhat.com, atomlin@redhat.com, uobergfe@redhat.com, tj@kernel.org, hidehiro.kawai.ez@hitachi.com, johunt@akamai.com, davem@davemloft.net, sparclinux@vger.kernel.org Cc: bp@suse.de, bywxiaobai@163.com, cmetcalf@mellanox.com, keescook@chromium.org, ebiederm@xmission.com, huawei.libin@huawei.com, ralf@linux-mips.org, dvyukov@google.com, linux-kernel@vger.kernel.org, sam@ravnborg.org, babu.moger@oracle.com Subject: [RFC PATCH 1/4] watchdog: Remove hardlockup handler references Date: Wed, 26 Oct 2016 09:02:20 -0700 Message-Id: <1477497743-15357-2-git-send-email-babu.moger@oracle.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1477497743-15357-1-git-send-email-babu.moger@oracle.com> References: <1477497743-15357-1-git-send-email-babu.moger@oracle.com> X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9138 Lines: 316 Separate hardlockup code from watchdog.c. It is mostly straight forward. Remove everything inside CONFIG_HARDLOCKUP_DETECTORS. This code will go to file watchdog_hld.c. We also define weak handlers watchdog_nmi_enable and watchdog_nmi_disable. Signed-off-by: Babu Moger --- kernel/watchdog.c | 251 ++--------------------------------------------------- 1 files changed, 7 insertions(+), 244 deletions(-) diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 9acb29f..a88e179 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -24,7 +24,6 @@ #include #include -#include #include /* @@ -100,50 +99,8 @@ static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts); static DEFINE_PER_CPU(unsigned long, soft_lockup_hrtimer_cnt); static DEFINE_PER_CPU(struct task_struct *, softlockup_task_ptr_saved); -#ifdef CONFIG_HARDLOCKUP_DETECTOR -static DEFINE_PER_CPU(bool, hard_watchdog_warn); -static DEFINE_PER_CPU(bool, watchdog_nmi_touch); -static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts_saved); -static DEFINE_PER_CPU(struct perf_event *, watchdog_ev); -#endif static unsigned long soft_lockup_nmi_warn; -/* boot commands */ -/* - * Should we panic when a soft-lockup or hard-lockup occurs: - */ -#ifdef CONFIG_HARDLOCKUP_DETECTOR -unsigned int __read_mostly hardlockup_panic = - CONFIG_BOOTPARAM_HARDLOCKUP_PANIC_VALUE; -static unsigned long hardlockup_allcpu_dumped; -/* - * We may not want to enable hard lockup detection by default in all cases, - * for example when running the kernel as a guest on a hypervisor. In these - * cases this function can be called to disable hard lockup detection. This - * function should only be executed once by the boot processor before the - * kernel command line parameters are parsed, because otherwise it is not - * possible to override this in hardlockup_panic_setup(). - */ -void hardlockup_detector_disable(void) -{ - watchdog_enabled &= ~NMI_WATCHDOG_ENABLED; -} - -static int __init hardlockup_panic_setup(char *str) -{ - if (!strncmp(str, "panic", 5)) - hardlockup_panic = 1; - else if (!strncmp(str, "nopanic", 7)) - hardlockup_panic = 0; - else if (!strncmp(str, "0", 1)) - watchdog_enabled &= ~NMI_WATCHDOG_ENABLED; - else if (!strncmp(str, "1", 1)) - watchdog_enabled |= NMI_WATCHDOG_ENABLED; - return 1; -} -__setup("nmi_watchdog=", hardlockup_panic_setup); -#endif - unsigned int __read_mostly softlockup_panic = CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC_VALUE; @@ -264,43 +221,12 @@ void touch_all_softlockup_watchdogs(void) wq_watchdog_touch(-1); } -#ifdef CONFIG_HARDLOCKUP_DETECTOR -void touch_nmi_watchdog(void) -{ - /* - * Using __raw here because some code paths have - * preemption enabled. If preemption is enabled - * then interrupts should be enabled too, in which - * case we shouldn't have to worry about the watchdog - * going off. - */ - raw_cpu_write(watchdog_nmi_touch, true); - touch_softlockup_watchdog(); -} -EXPORT_SYMBOL(touch_nmi_watchdog); - -#endif - void touch_softlockup_watchdog_sync(void) { __this_cpu_write(softlockup_touch_sync, true); __this_cpu_write(watchdog_touch_ts, 0); } -#ifdef CONFIG_HARDLOCKUP_DETECTOR -/* watchdog detector functions */ -static bool is_hardlockup(void) -{ - unsigned long hrint = __this_cpu_read(hrtimer_interrupts); - - if (__this_cpu_read(hrtimer_interrupts_saved) == hrint) - return true; - - __this_cpu_write(hrtimer_interrupts_saved, hrint); - return false; -} -#endif - static int is_softlockup(unsigned long touch_ts) { unsigned long now = get_timestamp(); @@ -313,78 +239,18 @@ static int is_softlockup(unsigned long touch_ts) return 0; } -#ifdef CONFIG_HARDLOCKUP_DETECTOR - -static struct perf_event_attr wd_hw_attr = { - .type = PERF_TYPE_HARDWARE, - .config = PERF_COUNT_HW_CPU_CYCLES, - .size = sizeof(struct perf_event_attr), - .pinned = 1, - .disabled = 1, -}; - -/* Callback function for perf event subsystem */ -static void watchdog_overflow_callback(struct perf_event *event, - struct perf_sample_data *data, - struct pt_regs *regs) -{ - /* Ensure the watchdog never gets throttled */ - event->hw.interrupts = 0; - - if (__this_cpu_read(watchdog_nmi_touch) == true) { - __this_cpu_write(watchdog_nmi_touch, false); - return; - } - - /* check for a hardlockup - * This is done by making sure our timer interrupt - * is incrementing. The timer interrupt should have - * fired multiple times before we overflow'd. If it hasn't - * then this is a good indication the cpu is stuck - */ - if (is_hardlockup()) { - int this_cpu = smp_processor_id(); - struct pt_regs *regs = get_irq_regs(); - - /* only print hardlockups once */ - if (__this_cpu_read(hard_watchdog_warn) == true) - return; - - pr_emerg("Watchdog detected hard LOCKUP on cpu %d", this_cpu); - print_modules(); - print_irqtrace_events(current); - if (regs) - show_regs(regs); - else - dump_stack(); - - /* - * Perform all-CPU dump only once to avoid multiple hardlockups - * generating interleaving traces - */ - if (sysctl_hardlockup_all_cpu_backtrace && - !test_and_set_bit(0, &hardlockup_allcpu_dumped)) - trigger_allbutself_cpu_backtrace(); - - if (hardlockup_panic) - nmi_panic(regs, "Hard LOCKUP"); - - __this_cpu_write(hard_watchdog_warn, true); - return; - } - - __this_cpu_write(hard_watchdog_warn, false); - return; -} -#endif /* CONFIG_HARDLOCKUP_DETECTOR */ - static void watchdog_interrupt_count(void) { __this_cpu_inc(hrtimer_interrupts); } -static int watchdog_nmi_enable(unsigned int cpu); -static void watchdog_nmi_disable(unsigned int cpu); +int __weak watchdog_nmi_enable(unsigned int cpu) +{ + return 0; +} +void __weak watchdog_nmi_disable(unsigned int cpu) +{ +} static int watchdog_enable_all_cpus(void); static void watchdog_disable_all_cpus(void); @@ -577,109 +443,6 @@ static void watchdog(unsigned int cpu) watchdog_nmi_disable(cpu); } -#ifdef CONFIG_HARDLOCKUP_DETECTOR -/* - * People like the simple clean cpu node info on boot. - * Reduce the watchdog noise by only printing messages - * that are different from what cpu0 displayed. - */ -static unsigned long cpu0_err; - -static int watchdog_nmi_enable(unsigned int cpu) -{ - struct perf_event_attr *wd_attr; - struct perf_event *event = per_cpu(watchdog_ev, cpu); - - /* nothing to do if the hard lockup detector is disabled */ - if (!(watchdog_enabled & NMI_WATCHDOG_ENABLED)) - goto out; - - /* is it already setup and enabled? */ - if (event && event->state > PERF_EVENT_STATE_OFF) - goto out; - - /* it is setup but not enabled */ - if (event != NULL) - goto out_enable; - - wd_attr = &wd_hw_attr; - wd_attr->sample_period = hw_nmi_get_sample_period(watchdog_thresh); - - /* Try to register using hardware perf events */ - event = perf_event_create_kernel_counter(wd_attr, cpu, NULL, watchdog_overflow_callback, NULL); - - /* save cpu0 error for future comparision */ - if (cpu == 0 && IS_ERR(event)) - cpu0_err = PTR_ERR(event); - - if (!IS_ERR(event)) { - /* only print for cpu0 or different than cpu0 */ - if (cpu == 0 || cpu0_err) - pr_info("enabled on all CPUs, permanently consumes one hw-PMU counter.\n"); - goto out_save; - } - - /* - * Disable the hard lockup detector if _any_ CPU fails to set up - * set up the hardware perf event. The watchdog() function checks - * the NMI_WATCHDOG_ENABLED bit periodically. - * - * The barriers are for syncing up watchdog_enabled across all the - * cpus, as clear_bit() does not use barriers. - */ - smp_mb__before_atomic(); - clear_bit(NMI_WATCHDOG_ENABLED_BIT, &watchdog_enabled); - smp_mb__after_atomic(); - - /* skip displaying the same error again */ - if (cpu > 0 && (PTR_ERR(event) == cpu0_err)) - return PTR_ERR(event); - - /* vary the KERN level based on the returned errno */ - if (PTR_ERR(event) == -EOPNOTSUPP) - pr_info("disabled (cpu%i): not supported (no LAPIC?)\n", cpu); - else if (PTR_ERR(event) == -ENOENT) - pr_warn("disabled (cpu%i): hardware events not enabled\n", - cpu); - else - pr_err("disabled (cpu%i): unable to create perf event: %ld\n", - cpu, PTR_ERR(event)); - - pr_info("Shutting down hard lockup detector on all cpus\n"); - - return PTR_ERR(event); - - /* success path */ -out_save: - per_cpu(watchdog_ev, cpu) = event; -out_enable: - perf_event_enable(per_cpu(watchdog_ev, cpu)); -out: - return 0; -} - -static void watchdog_nmi_disable(unsigned int cpu) -{ - struct perf_event *event = per_cpu(watchdog_ev, cpu); - - if (event) { - perf_event_disable(event); - per_cpu(watchdog_ev, cpu) = NULL; - - /* should be in cleanup, but blocks oprofile */ - perf_event_release_kernel(event); - } - if (cpu == 0) { - /* watchdog_nmi_enable() expects this to be zero initially. */ - cpu0_err = 0; - } -} - -#else -static int watchdog_nmi_enable(unsigned int cpu) { return 0; } -static void watchdog_nmi_disable(unsigned int cpu) { return; } -#endif /* CONFIG_HARDLOCKUP_DETECTOR */ - static struct smp_hotplug_thread watchdog_threads = { .store = &softlockup_watchdog, .thread_should_run = watchdog_should_run, -- 1.7.1