Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * latencytop.c: Latency display infrastructure
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  * (C) Copyright 2008 Intel Corporation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  * Author: Arjan van de Ven <arjan@linux.intel.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10)  * CONFIG_LATENCYTOP enables a kernel latency tracking infrastructure that is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11)  * used by the "latencytop" userspace tool. The latency that is tracked is not
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12)  * the 'traditional' interrupt latency (which is primarily caused by something
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13)  * else consuming CPU), but instead, it is the latency an application encounters
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14)  * because the kernel sleeps on its behalf for various reasons.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16)  * This code tracks 2 levels of statistics:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17)  * 1) System level latency
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18)  * 2) Per process latency
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20)  * The latency is stored in fixed sized data structures in an accumulated form;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21)  * if the "same" latency cause is hit twice, this will be tracked as one entry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22)  * in the data structure. Both the count, total accumulated latency and maximum
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23)  * latency are tracked in this data structure. When the fixed size structure is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24)  * full, no new causes are tracked until the buffer is flushed by writing to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25)  * the /proc file; the userspace tool does this on a regular basis.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27)  * A latency cause is identified by a stringified backtrace at the point that
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28)  * the scheduler gets invoked. The userland tool will use this string to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29)  * identify the cause of the latency in human readable form.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31)  * The information is exported via /proc/latency_stats and /proc/<pid>/latency.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32)  * These files look like this:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34)  * Latency Top version : v0.1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35)  * 70 59433 4897 i915_irq_wait drm_ioctl vfs_ioctl do_vfs_ioctl sys_ioctl
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36)  * |    |    |    |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37)  * |    |    |    +----> the stringified backtrace
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38)  * |    |    +---------> The maximum latency for this entry in microseconds
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39)  * |    +--------------> The accumulated latency for this entry (microseconds)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40)  * +-------------------> The number of times this entry is hit
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42)  * (note: the average latency is the accumulated latency divided by the number
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43)  * of times)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) #include <linux/kallsyms.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) #include <linux/seq_file.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) #include <linux/notifier.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) #include <linux/spinlock.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) #include <linux/proc_fs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) #include <linux/latencytop.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) #include <linux/export.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) #include <linux/sched.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) #include <linux/sched/debug.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) #include <linux/sched/stat.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) #include <linux/list.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) #include <linux/stacktrace.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) static DEFINE_RAW_SPINLOCK(latency_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) #define MAXLR 128
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) static struct latency_record latency_record[MAXLR];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) int latencytop_enabled;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) void clear_tsk_latency_tracing(struct task_struct *p)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 	unsigned long flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 	raw_spin_lock_irqsave(&latency_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 	memset(&p->latency_record, 0, sizeof(p->latency_record));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 	p->latency_record_count = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 	raw_spin_unlock_irqrestore(&latency_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) static void clear_global_latency_tracing(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 	unsigned long flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 	raw_spin_lock_irqsave(&latency_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 	memset(&latency_record, 0, sizeof(latency_record));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 	raw_spin_unlock_irqrestore(&latency_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) static void __sched
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) account_global_scheduler_latency(struct task_struct *tsk,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 				 struct latency_record *lat)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 	int firstnonnull = MAXLR + 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 	int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 	/* skip kernel threads for now */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 	if (!tsk->mm)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 	for (i = 0; i < MAXLR; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 		int q, same = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 		/* Nothing stored: */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 		if (!latency_record[i].backtrace[0]) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 			if (firstnonnull > i)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 				firstnonnull = i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 			continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 		for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 			unsigned long record = lat->backtrace[q];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 			if (latency_record[i].backtrace[q] != record) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 				same = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 				break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 			/* 0 entry marks end of backtrace: */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 			if (!record)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 				break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 		if (same) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 			latency_record[i].count++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 			latency_record[i].time += lat->time;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 			if (lat->time > latency_record[i].max)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 				latency_record[i].max = lat->time;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 			return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 	i = firstnonnull;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 	if (i >= MAXLR - 1)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 	/* Allocted a new one: */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 	memcpy(&latency_record[i], lat, sizeof(struct latency_record));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135)  * __account_scheduler_latency - record an occurred latency
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136)  * @tsk - the task struct of the task hitting the latency
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137)  * @usecs - the duration of the latency in microseconds
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138)  * @inter - 1 if the sleep was interruptible, 0 if uninterruptible
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140)  * This function is the main entry point for recording latency entries
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141)  * as called by the scheduler.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143)  * This function has a few special cases to deal with normal 'non-latency'
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144)  * sleeps: specifically, interruptible sleep longer than 5 msec is skipped
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145)  * since this usually is caused by waiting for events via select() and co.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147)  * Negative latencies (caused by time going backwards) are also explicitly
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148)  * skipped.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) void __sched
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) __account_scheduler_latency(struct task_struct *tsk, int usecs, int inter)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 	unsigned long flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 	int i, q;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 	struct latency_record lat;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 	/* Long interruptible waits are generally user requested... */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 	if (inter && usecs > 5000)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 	/* Negative sleeps are time going backwards */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 	/* Zero-time sleeps are non-interesting */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 	if (usecs <= 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 	memset(&lat, 0, sizeof(lat));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	lat.count = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 	lat.time = usecs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 	lat.max = usecs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 	stack_trace_save_tsk(tsk, lat.backtrace, LT_BACKTRACEDEPTH, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 	raw_spin_lock_irqsave(&latency_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 	account_global_scheduler_latency(tsk, &lat);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 	for (i = 0; i < tsk->latency_record_count; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 		struct latency_record *mylat;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 		int same = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 		mylat = &tsk->latency_record[i];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 		for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 			unsigned long record = lat.backtrace[q];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 			if (mylat->backtrace[q] != record) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 				same = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 				break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 			/* 0 entry is end of backtrace */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 			if (!record)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 				break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 		if (same) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 			mylat->count++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 			mylat->time += lat.time;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 			if (lat.time > mylat->max)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 				mylat->max = lat.time;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 			goto out_unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 	 * short term hack; if we're > 32 we stop; future we recycle:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 	if (tsk->latency_record_count >= LT_SAVECOUNT)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 		goto out_unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 	/* Allocated a new one: */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 	i = tsk->latency_record_count++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 	memcpy(&tsk->latency_record[i], &lat, sizeof(struct latency_record));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) out_unlock:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 	raw_spin_unlock_irqrestore(&latency_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) static int lstats_show(struct seq_file *m, void *v)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 	int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 	seq_puts(m, "Latency Top version : v0.1\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 	for (i = 0; i < MAXLR; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) 		struct latency_record *lr = &latency_record[i];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 		if (lr->backtrace[0]) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) 			int q;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) 			seq_printf(m, "%i %lu %lu",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) 				   lr->count, lr->time, lr->max);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) 			for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) 				unsigned long bt = lr->backtrace[q];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) 				if (!bt)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) 					break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) 				seq_printf(m, " %ps", (void *)bt);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) 			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) 			seq_puts(m, "\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) static ssize_t
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) lstats_write(struct file *file, const char __user *buf, size_t count,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) 	     loff_t *offs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 	clear_global_latency_tracing();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 	return count;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) static int lstats_open(struct inode *inode, struct file *filp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) 	return single_open(filp, lstats_show, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) static const struct proc_ops lstats_proc_ops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) 	.proc_open	= lstats_open,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) 	.proc_read	= seq_read,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) 	.proc_write	= lstats_write,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 	.proc_lseek	= seq_lseek,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 	.proc_release	= single_release,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) static int __init init_lstats_procfs(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) 	proc_create("latency_stats", 0644, NULL, &lstats_proc_ops);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) int sysctl_latencytop(struct ctl_table *table, int write, void *buffer,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) 		size_t *lenp, loff_t *ppos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) 	int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) 	err = proc_dointvec(table, write, buffer, lenp, ppos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) 	if (latencytop_enabled)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) 		force_schedstat_enabled();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) 	return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) device_initcall(init_lstats_procfs);