Revision e2921f9f95f1c1355a39e54dc038ad95b6e032be authored by Linus Torvalds on 26 July 2019, 21:12:54 UTC, committed by Linus Torvalds on 26 July 2019, 21:12:54 UTC
Pull drm fixes from Daniel Vetter: "Dave seems to collect an entire streak of things happening, so again me typing pull summary. Nothing nefarious here, most of the fixes are for new stuff or things users won't see. The amd-display patches are a bit different, and very much look like they should have at least some cc: stable tags. Might be amd is a bit too comfortable with their internal tree and not enough looking at upstream. Dave&me are looking into this, in case something needs rectified with process here. Also no intel fixes pull, but intel CI is general become rather good, still I guess expect a notch more for -rc3. Summary: amdgpu: - fixes for (new in 5.3) hw support (vega20, navi) - disable RAS - lots of display fixes all over (audio, DSC, dongle, clock mgr) ttm: - fix dma_free_attrs calls to appease dma debugging msm: - fixes for dma-api, locking debug and compiler splats core: - fix cmdline mode to not apply rotation if not specified (new in 5.3) - compiler warn fix" * tag 'drm-fixes-2019-07-26' of git://anongit.freedesktop.org/drm/drm: (46 commits) drm/amd/display: Set enabled to false at start of audio disable drm/amdgpu/smu: move fan rpm query into the asic specific code drm/amd/powerplay: custom peak clock freq for navi10 drm: silence variable 'conn' set but not used drm/msm: stop abusing dma_map/unmap for cache drm/msm/dpu: Correct dpu encoder spinlock initialization drm/msm: correct NULL pointer dereference in context_init drm/amd/display: handle active dongle port type is DP++ or DP case drm/amd/display: do not read link setting if edp not connected drm/amd/display: Increase size of audios array drm/amd/display: drop ASSERT() if eDP panel is not connected drm/amd/display: Only enable audio if speaker allocation exists drm/amd/display: Fix dc_create failure handling and 666 color depths drm/amd/display: allocate 4 ddc engines for RV2 drm/amd/display: put back front end initialization sequence drm/amd/display: Wait for flip to complete drm/amd/display: Change min_h_sync_width from 8 to 4 drm/amd/display: use encoder's engine id to find matched free audio device drm/amd/display: fix DMCU hang when going into Modern Standby drm/amd/display: Disable Audio on reinitialize hardware ...
latencytop.c
// 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>
*/
/*
* CONFIG_LATENCYTOP enables a kernel latency tracking infrastructure that is
* used by the "latencytop" userspace tool. The latency that is tracked is not
* the 'traditional' interrupt latency (which is primarily caused by something
* else consuming CPU), but instead, it is the latency an application encounters
* because the kernel sleeps on its behalf for various reasons.
*
* This code tracks 2 levels of statistics:
* 1) System level latency
* 2) Per process latency
*
* The latency is stored in fixed sized data structures in an accumulated form;
* if the "same" latency cause is hit twice, this will be tracked as one entry
* in the data structure. Both the count, total accumulated latency and maximum
* latency are tracked in this data structure. When the fixed size structure is
* full, no new causes are tracked until the buffer is flushed by writing to
* the /proc file; the userspace tool does this on a regular basis.
*
* A latency cause is identified by a stringified backtrace at the point that
* the scheduler gets invoked. The userland tool will use this string to
* identify the cause of the latency in human readable form.
*
* The information is exported via /proc/latency_stats and /proc/<pid>/latency.
* These files look like this:
*
* Latency Top version : v0.1
* 70 59433 4897 i915_irq_wait drm_ioctl vfs_ioctl do_vfs_ioctl sys_ioctl
* | | | |
* | | | +----> the stringified backtrace
* | | +---------> The maximum latency for this entry in microseconds
* | +--------------> The accumulated latency for this entry (microseconds)
* +-------------------> The number of times this entry is hit
*
* (note: the average latency is the accumulated latency divided by the number
* of times)
*/
#include <linux/kallsyms.h>
#include <linux/seq_file.h>
#include <linux/notifier.h>
#include <linux/spinlock.h>
#include <linux/proc_fs.h>
#include <linux/latencytop.h>
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/sched/stat.h>
#include <linux/list.h>
#include <linux/stacktrace.h>
static DEFINE_RAW_SPINLOCK(latency_lock);
#define MAXLR 128
static struct latency_record latency_record[MAXLR];
int latencytop_enabled;
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));
p->latency_record_count = 0;
raw_spin_unlock_irqrestore(&latency_lock, flags);
}
static void clear_global_latency_tracing(void)
{
unsigned long flags;
raw_spin_lock_irqsave(&latency_lock, flags);
memset(&latency_record, 0, sizeof(latency_record));
raw_spin_unlock_irqrestore(&latency_lock, flags);
}
static void __sched
account_global_scheduler_latency(struct task_struct *tsk,
struct latency_record *lat)
{
int firstnonnull = MAXLR + 1;
int i;
/* skip kernel threads for now */
if (!tsk->mm)
return;
for (i = 0; i < MAXLR; i++) {
int q, same = 1;
/* Nothing stored: */
if (!latency_record[i].backtrace[0]) {
if (firstnonnull > i)
firstnonnull = i;
continue;
}
for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
unsigned long record = lat->backtrace[q];
if (latency_record[i].backtrace[q] != record) {
same = 0;
break;
}
/* 0 entry marks end of backtrace: */
if (!record)
break;
}
if (same) {
latency_record[i].count++;
latency_record[i].time += lat->time;
if (lat->time > latency_record[i].max)
latency_record[i].max = lat->time;
return;
}
}
i = firstnonnull;
if (i >= MAXLR - 1)
return;
/* Allocted a new one: */
memcpy(&latency_record[i], lat, sizeof(struct latency_record));
}
/**
* __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
*
* This function is the main entry point for recording latency entries
* as called by the scheduler.
*
* This function has a few special cases to deal with normal 'non-latency'
* sleeps: specifically, interruptible sleep longer than 5 msec is skipped
* since this usually is caused by waiting for events via select() and co.
*
* Negative latencies (caused by time going backwards) are also explicitly
* skipped.
*/
void __sched
__account_scheduler_latency(struct task_struct *tsk, int usecs, int inter)
{
unsigned long flags;
int i, q;
struct latency_record lat;
/* Long interruptible waits are generally user requested... */
if (inter && usecs > 5000)
return;
/* Negative sleeps are time going backwards */
/* Zero-time sleeps are non-interesting */
if (usecs <= 0)
return;
memset(&lat, 0, sizeof(lat));
lat.count = 1;
lat.time = usecs;
lat.max = usecs;
stack_trace_save_tsk(tsk, lat.backtrace, LT_BACKTRACEDEPTH, 0);
raw_spin_lock_irqsave(&latency_lock, flags);
account_global_scheduler_latency(tsk, &lat);
for (i = 0; i < tsk->latency_record_count; i++) {
struct latency_record *mylat;
int same = 1;
mylat = &tsk->latency_record[i];
for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
unsigned long record = lat.backtrace[q];
if (mylat->backtrace[q] != record) {
same = 0;
break;
}
/* 0 entry is end of backtrace */
if (!record)
break;
}
if (same) {
mylat->count++;
mylat->time += lat.time;
if (lat.time > mylat->max)
mylat->max = lat.time;
goto out_unlock;
}
}
/*
* short term hack; if we're > 32 we stop; future we recycle:
*/
if (tsk->latency_record_count >= LT_SAVECOUNT)
goto out_unlock;
/* Allocated a new one: */
i = tsk->latency_record_count++;
memcpy(&tsk->latency_record[i], &lat, sizeof(struct latency_record));
out_unlock:
raw_spin_unlock_irqrestore(&latency_lock, flags);
}
static int lstats_show(struct seq_file *m, void *v)
{
int i;
seq_puts(m, "Latency Top version : v0.1\n");
for (i = 0; i < MAXLR; i++) {
struct latency_record *lr = &latency_record[i];
if (lr->backtrace[0]) {
int q;
seq_printf(m, "%i %lu %lu",
lr->count, lr->time, lr->max);
for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
unsigned long bt = lr->backtrace[q];
if (!bt)
break;
seq_printf(m, " %ps", (void *)bt);
}
seq_puts(m, "\n");
}
}
return 0;
}
static ssize_t
lstats_write(struct file *file, const char __user *buf, size_t count,
loff_t *offs)
{
clear_global_latency_tracing();
return count;
}
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 int __init init_lstats_procfs(void)
{
proc_create("latency_stats", 0644, NULL, &lstats_fops);
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);
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