diff options
Diffstat (limited to 'kernel/latencytop.c')
| -rw-r--r-- | kernel/latencytop.c | 107 |
1 files changed, 50 insertions, 57 deletions
diff --git a/kernel/latencytop.c b/kernel/latencytop.c index 96b4179cee6a..d4281d1e13a6 100644 --- a/kernel/latencytop.c +++ b/kernel/latencytop.c @@ -1,13 +1,9 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * latencytop.c: Latency display infrastructure * * (C) Copyright 2008 Intel Corporation * Author: Arjan van de Ven <arjan@linux.intel.com> - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; version 2 - * of the License. */ /* @@ -59,6 +55,7 @@ #include <linux/sched/stat.h> #include <linux/list.h> #include <linux/stacktrace.h> +#include <linux/sysctl.h> static DEFINE_RAW_SPINLOCK(latency_lock); @@ -67,12 +64,33 @@ static struct latency_record latency_record[MAXLR]; int latencytop_enabled; -void clear_all_latency_tracing(struct task_struct *p) +#ifdef CONFIG_SYSCTL +static int sysctl_latencytop(const struct ctl_table *table, int write, void *buffer, + size_t *lenp, loff_t *ppos) { - unsigned long flags; + int err; - if (!latencytop_enabled) - return; + err = proc_dointvec(table, write, buffer, lenp, ppos); + if (latencytop_enabled) + force_schedstat_enabled(); + + return err; +} + +static const struct ctl_table latencytop_sysctl[] = { + { + .procname = "latencytop", + .data = &latencytop_enabled, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = sysctl_latencytop, + }, +}; +#endif + +void clear_tsk_latency_tracing(struct task_struct *p) +{ + unsigned long flags; raw_spin_lock_irqsave(&latency_lock, flags); memset(&p->latency_record, 0, sizeof(p->latency_record)); @@ -93,12 +111,9 @@ static void __sched account_global_scheduler_latency(struct task_struct *tsk, struct latency_record *lat) { - int firstnonnull = MAXLR + 1; + int firstnonnull = MAXLR; int i; - if (!latencytop_enabled) - return; - /* skip kernel threads for now */ if (!tsk->mm) return; @@ -120,8 +135,8 @@ account_global_scheduler_latency(struct task_struct *tsk, break; } - /* 0 and ULONG_MAX entries mean end of backtrace: */ - if (record == 0 || record == ULONG_MAX) + /* 0 entry marks end of backtrace: */ + if (!record) break; } if (same) { @@ -134,32 +149,18 @@ account_global_scheduler_latency(struct task_struct *tsk, } i = firstnonnull; - if (i >= MAXLR - 1) + if (i >= MAXLR) return; /* Allocted a new one: */ memcpy(&latency_record[i], lat, sizeof(struct latency_record)); } -/* - * Iterator to store a backtrace into a latency record entry - */ -static inline void store_stacktrace(struct task_struct *tsk, - struct latency_record *lat) -{ - struct stack_trace trace; - - memset(&trace, 0, sizeof(trace)); - trace.max_entries = LT_BACKTRACEDEPTH; - trace.entries = &lat->backtrace[0]; - save_stack_trace_tsk(tsk, &trace); -} - /** * __account_scheduler_latency - record an occurred latency - * @tsk - the task struct of the task hitting the latency - * @usecs - the duration of the latency in microseconds - * @inter - 1 if the sleep was interruptible, 0 if uninterruptible + * @tsk: the task struct of the task hitting the latency + * @usecs: the duration of the latency in microseconds + * @inter: 1 if the sleep was interruptible, 0 if uninterruptible * * This function is the main entry point for recording latency entries * as called by the scheduler. @@ -191,7 +192,8 @@ __account_scheduler_latency(struct task_struct *tsk, int usecs, int inter) lat.count = 1; lat.time = usecs; lat.max = usecs; - store_stacktrace(tsk, &lat); + + stack_trace_save_tsk(tsk, lat.backtrace, LT_BACKTRACEDEPTH, 0); raw_spin_lock_irqsave(&latency_lock, flags); @@ -210,8 +212,8 @@ __account_scheduler_latency(struct task_struct *tsk, int usecs, int inter) break; } - /* 0 and ULONG_MAX entries mean end of backtrace: */ - if (record == 0 || record == ULONG_MAX) + /* 0 entry is end of backtrace */ + if (!record) break; } if (same) { @@ -252,10 +254,10 @@ static int lstats_show(struct seq_file *m, void *v) lr->count, lr->time, lr->max); for (q = 0; q < LT_BACKTRACEDEPTH; q++) { unsigned long bt = lr->backtrace[q]; + if (!bt) break; - if (bt == ULONG_MAX) - break; + seq_printf(m, " %ps", (void *)bt); } seq_puts(m, "\n"); @@ -278,29 +280,20 @@ static int lstats_open(struct inode *inode, struct file *filp) return single_open(filp, lstats_show, NULL); } -static const struct file_operations lstats_fops = { - .open = lstats_open, - .read = seq_read, - .write = lstats_write, - .llseek = seq_lseek, - .release = single_release, +static const struct proc_ops lstats_proc_ops = { + .proc_open = lstats_open, + .proc_read = seq_read, + .proc_write = lstats_write, + .proc_lseek = seq_lseek, + .proc_release = single_release, }; static int __init init_lstats_procfs(void) { - proc_create("latency_stats", 0644, NULL, &lstats_fops); + proc_create("latency_stats", 0644, NULL, &lstats_proc_ops); +#ifdef CONFIG_SYSCTL + register_sysctl_init("kernel", latencytop_sysctl); +#endif return 0; } - -int sysctl_latencytop(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) -{ - int err; - - err = proc_dointvec(table, write, buffer, lenp, ppos); - if (latencytop_enabled) - force_schedstat_enabled(); - - return err; -} device_initcall(init_lstats_procfs); |