mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-06 04:16:39 +07:00
608dfddd84
Change cpu_buffer from array to per_cpu variable in oprofile functions. [akpm@linux-foundation.org: coding-style fixes] Cc: Philippe Elie <phil.el@wanadoo.fr> Signed-off-by: Mike Travis <travis@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
554 lines
13 KiB
C
554 lines
13 KiB
C
/**
|
|
* @file buffer_sync.c
|
|
*
|
|
* @remark Copyright 2002 OProfile authors
|
|
* @remark Read the file COPYING
|
|
*
|
|
* @author John Levon <levon@movementarian.org>
|
|
*
|
|
* This is the core of the buffer management. Each
|
|
* CPU buffer is processed and entered into the
|
|
* global event buffer. Such processing is necessary
|
|
* in several circumstances, mentioned below.
|
|
*
|
|
* The processing does the job of converting the
|
|
* transitory EIP value into a persistent dentry/offset
|
|
* value that the profiler can record at its leisure.
|
|
*
|
|
* See fs/dcookies.c for a description of the dentry/offset
|
|
* objects.
|
|
*/
|
|
|
|
#include <linux/mm.h>
|
|
#include <linux/workqueue.h>
|
|
#include <linux/notifier.h>
|
|
#include <linux/dcookies.h>
|
|
#include <linux/profile.h>
|
|
#include <linux/module.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/oprofile.h>
|
|
#include <linux/sched.h>
|
|
|
|
#include "oprofile_stats.h"
|
|
#include "event_buffer.h"
|
|
#include "cpu_buffer.h"
|
|
#include "buffer_sync.h"
|
|
|
|
static LIST_HEAD(dying_tasks);
|
|
static LIST_HEAD(dead_tasks);
|
|
static cpumask_t marked_cpus = CPU_MASK_NONE;
|
|
static DEFINE_SPINLOCK(task_mortuary);
|
|
static void process_task_mortuary(void);
|
|
|
|
|
|
/* Take ownership of the task struct and place it on the
|
|
* list for processing. Only after two full buffer syncs
|
|
* does the task eventually get freed, because by then
|
|
* we are sure we will not reference it again.
|
|
* Can be invoked from softirq via RCU callback due to
|
|
* call_rcu() of the task struct, hence the _irqsave.
|
|
*/
|
|
static int task_free_notify(struct notifier_block * self, unsigned long val, void * data)
|
|
{
|
|
unsigned long flags;
|
|
struct task_struct * task = data;
|
|
spin_lock_irqsave(&task_mortuary, flags);
|
|
list_add(&task->tasks, &dying_tasks);
|
|
spin_unlock_irqrestore(&task_mortuary, flags);
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
|
|
/* The task is on its way out. A sync of the buffer means we can catch
|
|
* any remaining samples for this task.
|
|
*/
|
|
static int task_exit_notify(struct notifier_block * self, unsigned long val, void * data)
|
|
{
|
|
/* To avoid latency problems, we only process the current CPU,
|
|
* hoping that most samples for the task are on this CPU
|
|
*/
|
|
sync_buffer(raw_smp_processor_id());
|
|
return 0;
|
|
}
|
|
|
|
|
|
/* The task is about to try a do_munmap(). We peek at what it's going to
|
|
* do, and if it's an executable region, process the samples first, so
|
|
* we don't lose any. This does not have to be exact, it's a QoI issue
|
|
* only.
|
|
*/
|
|
static int munmap_notify(struct notifier_block * self, unsigned long val, void * data)
|
|
{
|
|
unsigned long addr = (unsigned long)data;
|
|
struct mm_struct * mm = current->mm;
|
|
struct vm_area_struct * mpnt;
|
|
|
|
down_read(&mm->mmap_sem);
|
|
|
|
mpnt = find_vma(mm, addr);
|
|
if (mpnt && mpnt->vm_file && (mpnt->vm_flags & VM_EXEC)) {
|
|
up_read(&mm->mmap_sem);
|
|
/* To avoid latency problems, we only process the current CPU,
|
|
* hoping that most samples for the task are on this CPU
|
|
*/
|
|
sync_buffer(raw_smp_processor_id());
|
|
return 0;
|
|
}
|
|
|
|
up_read(&mm->mmap_sem);
|
|
return 0;
|
|
}
|
|
|
|
|
|
/* We need to be told about new modules so we don't attribute to a previously
|
|
* loaded module, or drop the samples on the floor.
|
|
*/
|
|
static int module_load_notify(struct notifier_block * self, unsigned long val, void * data)
|
|
{
|
|
#ifdef CONFIG_MODULES
|
|
if (val != MODULE_STATE_COMING)
|
|
return 0;
|
|
|
|
/* FIXME: should we process all CPU buffers ? */
|
|
mutex_lock(&buffer_mutex);
|
|
add_event_entry(ESCAPE_CODE);
|
|
add_event_entry(MODULE_LOADED_CODE);
|
|
mutex_unlock(&buffer_mutex);
|
|
#endif
|
|
return 0;
|
|
}
|
|
|
|
|
|
static struct notifier_block task_free_nb = {
|
|
.notifier_call = task_free_notify,
|
|
};
|
|
|
|
static struct notifier_block task_exit_nb = {
|
|
.notifier_call = task_exit_notify,
|
|
};
|
|
|
|
static struct notifier_block munmap_nb = {
|
|
.notifier_call = munmap_notify,
|
|
};
|
|
|
|
static struct notifier_block module_load_nb = {
|
|
.notifier_call = module_load_notify,
|
|
};
|
|
|
|
|
|
static void end_sync(void)
|
|
{
|
|
end_cpu_work();
|
|
/* make sure we don't leak task structs */
|
|
process_task_mortuary();
|
|
process_task_mortuary();
|
|
}
|
|
|
|
|
|
int sync_start(void)
|
|
{
|
|
int err;
|
|
|
|
start_cpu_work();
|
|
|
|
err = task_handoff_register(&task_free_nb);
|
|
if (err)
|
|
goto out1;
|
|
err = profile_event_register(PROFILE_TASK_EXIT, &task_exit_nb);
|
|
if (err)
|
|
goto out2;
|
|
err = profile_event_register(PROFILE_MUNMAP, &munmap_nb);
|
|
if (err)
|
|
goto out3;
|
|
err = register_module_notifier(&module_load_nb);
|
|
if (err)
|
|
goto out4;
|
|
|
|
out:
|
|
return err;
|
|
out4:
|
|
profile_event_unregister(PROFILE_MUNMAP, &munmap_nb);
|
|
out3:
|
|
profile_event_unregister(PROFILE_TASK_EXIT, &task_exit_nb);
|
|
out2:
|
|
task_handoff_unregister(&task_free_nb);
|
|
out1:
|
|
end_sync();
|
|
goto out;
|
|
}
|
|
|
|
|
|
void sync_stop(void)
|
|
{
|
|
unregister_module_notifier(&module_load_nb);
|
|
profile_event_unregister(PROFILE_MUNMAP, &munmap_nb);
|
|
profile_event_unregister(PROFILE_TASK_EXIT, &task_exit_nb);
|
|
task_handoff_unregister(&task_free_nb);
|
|
end_sync();
|
|
}
|
|
|
|
|
|
/* Optimisation. We can manage without taking the dcookie sem
|
|
* because we cannot reach this code without at least one
|
|
* dcookie user still being registered (namely, the reader
|
|
* of the event buffer). */
|
|
static inline unsigned long fast_get_dcookie(struct path *path)
|
|
{
|
|
unsigned long cookie;
|
|
|
|
if (path->dentry->d_cookie)
|
|
return (unsigned long)path->dentry;
|
|
get_dcookie(path, &cookie);
|
|
return cookie;
|
|
}
|
|
|
|
|
|
/* Look up the dcookie for the task's first VM_EXECUTABLE mapping,
|
|
* which corresponds loosely to "application name". This is
|
|
* not strictly necessary but allows oprofile to associate
|
|
* shared-library samples with particular applications
|
|
*/
|
|
static unsigned long get_exec_dcookie(struct mm_struct * mm)
|
|
{
|
|
unsigned long cookie = NO_COOKIE;
|
|
struct vm_area_struct * vma;
|
|
|
|
if (!mm)
|
|
goto out;
|
|
|
|
for (vma = mm->mmap; vma; vma = vma->vm_next) {
|
|
if (!vma->vm_file)
|
|
continue;
|
|
if (!(vma->vm_flags & VM_EXECUTABLE))
|
|
continue;
|
|
cookie = fast_get_dcookie(&vma->vm_file->f_path);
|
|
break;
|
|
}
|
|
|
|
out:
|
|
return cookie;
|
|
}
|
|
|
|
|
|
/* Convert the EIP value of a sample into a persistent dentry/offset
|
|
* pair that can then be added to the global event buffer. We make
|
|
* sure to do this lookup before a mm->mmap modification happens so
|
|
* we don't lose track.
|
|
*/
|
|
static unsigned long lookup_dcookie(struct mm_struct * mm, unsigned long addr, off_t * offset)
|
|
{
|
|
unsigned long cookie = NO_COOKIE;
|
|
struct vm_area_struct * vma;
|
|
|
|
for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) {
|
|
|
|
if (addr < vma->vm_start || addr >= vma->vm_end)
|
|
continue;
|
|
|
|
if (vma->vm_file) {
|
|
cookie = fast_get_dcookie(&vma->vm_file->f_path);
|
|
*offset = (vma->vm_pgoff << PAGE_SHIFT) + addr -
|
|
vma->vm_start;
|
|
} else {
|
|
/* must be an anonymous map */
|
|
*offset = addr;
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
if (!vma)
|
|
cookie = INVALID_COOKIE;
|
|
|
|
return cookie;
|
|
}
|
|
|
|
|
|
static unsigned long last_cookie = INVALID_COOKIE;
|
|
|
|
static void add_cpu_switch(int i)
|
|
{
|
|
add_event_entry(ESCAPE_CODE);
|
|
add_event_entry(CPU_SWITCH_CODE);
|
|
add_event_entry(i);
|
|
last_cookie = INVALID_COOKIE;
|
|
}
|
|
|
|
static void add_kernel_ctx_switch(unsigned int in_kernel)
|
|
{
|
|
add_event_entry(ESCAPE_CODE);
|
|
if (in_kernel)
|
|
add_event_entry(KERNEL_ENTER_SWITCH_CODE);
|
|
else
|
|
add_event_entry(KERNEL_EXIT_SWITCH_CODE);
|
|
}
|
|
|
|
static void
|
|
add_user_ctx_switch(struct task_struct const * task, unsigned long cookie)
|
|
{
|
|
add_event_entry(ESCAPE_CODE);
|
|
add_event_entry(CTX_SWITCH_CODE);
|
|
add_event_entry(task->pid);
|
|
add_event_entry(cookie);
|
|
/* Another code for daemon back-compat */
|
|
add_event_entry(ESCAPE_CODE);
|
|
add_event_entry(CTX_TGID_CODE);
|
|
add_event_entry(task->tgid);
|
|
}
|
|
|
|
|
|
static void add_cookie_switch(unsigned long cookie)
|
|
{
|
|
add_event_entry(ESCAPE_CODE);
|
|
add_event_entry(COOKIE_SWITCH_CODE);
|
|
add_event_entry(cookie);
|
|
}
|
|
|
|
|
|
static void add_trace_begin(void)
|
|
{
|
|
add_event_entry(ESCAPE_CODE);
|
|
add_event_entry(TRACE_BEGIN_CODE);
|
|
}
|
|
|
|
|
|
static void add_sample_entry(unsigned long offset, unsigned long event)
|
|
{
|
|
add_event_entry(offset);
|
|
add_event_entry(event);
|
|
}
|
|
|
|
|
|
static int add_us_sample(struct mm_struct * mm, struct op_sample * s)
|
|
{
|
|
unsigned long cookie;
|
|
off_t offset;
|
|
|
|
cookie = lookup_dcookie(mm, s->eip, &offset);
|
|
|
|
if (cookie == INVALID_COOKIE) {
|
|
atomic_inc(&oprofile_stats.sample_lost_no_mapping);
|
|
return 0;
|
|
}
|
|
|
|
if (cookie != last_cookie) {
|
|
add_cookie_switch(cookie);
|
|
last_cookie = cookie;
|
|
}
|
|
|
|
add_sample_entry(offset, s->event);
|
|
|
|
return 1;
|
|
}
|
|
|
|
|
|
/* Add a sample to the global event buffer. If possible the
|
|
* sample is converted into a persistent dentry/offset pair
|
|
* for later lookup from userspace.
|
|
*/
|
|
static int
|
|
add_sample(struct mm_struct * mm, struct op_sample * s, int in_kernel)
|
|
{
|
|
if (in_kernel) {
|
|
add_sample_entry(s->eip, s->event);
|
|
return 1;
|
|
} else if (mm) {
|
|
return add_us_sample(mm, s);
|
|
} else {
|
|
atomic_inc(&oprofile_stats.sample_lost_no_mm);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
|
|
static void release_mm(struct mm_struct * mm)
|
|
{
|
|
if (!mm)
|
|
return;
|
|
up_read(&mm->mmap_sem);
|
|
mmput(mm);
|
|
}
|
|
|
|
|
|
static struct mm_struct * take_tasks_mm(struct task_struct * task)
|
|
{
|
|
struct mm_struct * mm = get_task_mm(task);
|
|
if (mm)
|
|
down_read(&mm->mmap_sem);
|
|
return mm;
|
|
}
|
|
|
|
|
|
static inline int is_code(unsigned long val)
|
|
{
|
|
return val == ESCAPE_CODE;
|
|
}
|
|
|
|
|
|
/* "acquire" as many cpu buffer slots as we can */
|
|
static unsigned long get_slots(struct oprofile_cpu_buffer * b)
|
|
{
|
|
unsigned long head = b->head_pos;
|
|
unsigned long tail = b->tail_pos;
|
|
|
|
/*
|
|
* Subtle. This resets the persistent last_task
|
|
* and in_kernel values used for switching notes.
|
|
* BUT, there is a small window between reading
|
|
* head_pos, and this call, that means samples
|
|
* can appear at the new head position, but not
|
|
* be prefixed with the notes for switching
|
|
* kernel mode or a task switch. This small hole
|
|
* can lead to mis-attribution or samples where
|
|
* we don't know if it's in the kernel or not,
|
|
* at the start of an event buffer.
|
|
*/
|
|
cpu_buffer_reset(b);
|
|
|
|
if (head >= tail)
|
|
return head - tail;
|
|
|
|
return head + (b->buffer_size - tail);
|
|
}
|
|
|
|
|
|
static void increment_tail(struct oprofile_cpu_buffer * b)
|
|
{
|
|
unsigned long new_tail = b->tail_pos + 1;
|
|
|
|
rmb();
|
|
|
|
if (new_tail < b->buffer_size)
|
|
b->tail_pos = new_tail;
|
|
else
|
|
b->tail_pos = 0;
|
|
}
|
|
|
|
|
|
/* Move tasks along towards death. Any tasks on dead_tasks
|
|
* will definitely have no remaining references in any
|
|
* CPU buffers at this point, because we use two lists,
|
|
* and to have reached the list, it must have gone through
|
|
* one full sync already.
|
|
*/
|
|
static void process_task_mortuary(void)
|
|
{
|
|
unsigned long flags;
|
|
LIST_HEAD(local_dead_tasks);
|
|
struct task_struct * task;
|
|
struct task_struct * ttask;
|
|
|
|
spin_lock_irqsave(&task_mortuary, flags);
|
|
|
|
list_splice_init(&dead_tasks, &local_dead_tasks);
|
|
list_splice_init(&dying_tasks, &dead_tasks);
|
|
|
|
spin_unlock_irqrestore(&task_mortuary, flags);
|
|
|
|
list_for_each_entry_safe(task, ttask, &local_dead_tasks, tasks) {
|
|
list_del(&task->tasks);
|
|
free_task(task);
|
|
}
|
|
}
|
|
|
|
|
|
static void mark_done(int cpu)
|
|
{
|
|
int i;
|
|
|
|
cpu_set(cpu, marked_cpus);
|
|
|
|
for_each_online_cpu(i) {
|
|
if (!cpu_isset(i, marked_cpus))
|
|
return;
|
|
}
|
|
|
|
/* All CPUs have been processed at least once,
|
|
* we can process the mortuary once
|
|
*/
|
|
process_task_mortuary();
|
|
|
|
cpus_clear(marked_cpus);
|
|
}
|
|
|
|
|
|
/* FIXME: this is not sufficient if we implement syscall barrier backtrace
|
|
* traversal, the code switch to sb_sample_start at first kernel enter/exit
|
|
* switch so we need a fifth state and some special handling in sync_buffer()
|
|
*/
|
|
typedef enum {
|
|
sb_bt_ignore = -2,
|
|
sb_buffer_start,
|
|
sb_bt_start,
|
|
sb_sample_start,
|
|
} sync_buffer_state;
|
|
|
|
/* Sync one of the CPU's buffers into the global event buffer.
|
|
* Here we need to go through each batch of samples punctuated
|
|
* by context switch notes, taking the task's mmap_sem and doing
|
|
* lookup in task->mm->mmap to convert EIP into dcookie/offset
|
|
* value.
|
|
*/
|
|
void sync_buffer(int cpu)
|
|
{
|
|
struct oprofile_cpu_buffer *cpu_buf = &per_cpu(cpu_buffer, cpu);
|
|
struct mm_struct *mm = NULL;
|
|
struct task_struct * new;
|
|
unsigned long cookie = 0;
|
|
int in_kernel = 1;
|
|
unsigned int i;
|
|
sync_buffer_state state = sb_buffer_start;
|
|
unsigned long available;
|
|
|
|
mutex_lock(&buffer_mutex);
|
|
|
|
add_cpu_switch(cpu);
|
|
|
|
/* Remember, only we can modify tail_pos */
|
|
|
|
available = get_slots(cpu_buf);
|
|
|
|
for (i = 0; i < available; ++i) {
|
|
struct op_sample * s = &cpu_buf->buffer[cpu_buf->tail_pos];
|
|
|
|
if (is_code(s->eip)) {
|
|
if (s->event <= CPU_IS_KERNEL) {
|
|
/* kernel/userspace switch */
|
|
in_kernel = s->event;
|
|
if (state == sb_buffer_start)
|
|
state = sb_sample_start;
|
|
add_kernel_ctx_switch(s->event);
|
|
} else if (s->event == CPU_TRACE_BEGIN) {
|
|
state = sb_bt_start;
|
|
add_trace_begin();
|
|
} else {
|
|
struct mm_struct * oldmm = mm;
|
|
|
|
/* userspace context switch */
|
|
new = (struct task_struct *)s->event;
|
|
|
|
release_mm(oldmm);
|
|
mm = take_tasks_mm(new);
|
|
if (mm != oldmm)
|
|
cookie = get_exec_dcookie(mm);
|
|
add_user_ctx_switch(new, cookie);
|
|
}
|
|
} else {
|
|
if (state >= sb_bt_start &&
|
|
!add_sample(mm, s, in_kernel)) {
|
|
if (state == sb_bt_start) {
|
|
state = sb_bt_ignore;
|
|
atomic_inc(&oprofile_stats.bt_lost_no_mapping);
|
|
}
|
|
}
|
|
}
|
|
|
|
increment_tail(cpu_buf);
|
|
}
|
|
release_mm(mm);
|
|
|
|
mark_done(cpu);
|
|
|
|
mutex_unlock(&buffer_mutex);
|
|
}
|