diff options
Diffstat (limited to 'drivers/oprofile/buffer_sync.c')
| -rw-r--r-- | drivers/oprofile/buffer_sync.c | 591 |
1 files changed, 0 insertions, 591 deletions
diff --git a/drivers/oprofile/buffer_sync.c b/drivers/oprofile/buffer_sync.c deleted file mode 100644 index cc917865f13a..000000000000 --- a/drivers/oprofile/buffer_sync.c +++ /dev/null @@ -1,591 +0,0 @@ -/** - * @file buffer_sync.c - * - * @remark Copyright 2002-2009 OProfile authors - * @remark Read the file COPYING - * - * @author John Levon <levon@movementarian.org> - * @author Barry Kasindorf - * @author Robert Richter <robert.richter@amd.com> - * - * 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/file.h> -#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 <linux/sched/mm.h> -#include <linux/sched/task.h> -#include <linux/gfp.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_var_t marked_cpus; -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; - - mmap_read_lock(mm); - - mpnt = find_vma(mm, addr); - if (mpnt && mpnt->vm_file && (mpnt->vm_flags & VM_EXEC)) { - mmap_read_unlock(mm); - /* 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; - } - - mmap_read_unlock(mm); - 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 NOTIFY_DONE; - - /* 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 NOTIFY_OK; -} - - -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 free_all_tasks(void) -{ - /* make sure we don't leak task structs */ - process_task_mortuary(); - process_task_mortuary(); -} - -int sync_start(void) -{ - int err; - - if (!zalloc_cpumask_var(&marked_cpus, GFP_KERNEL)) - return -ENOMEM; - - 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; - - start_cpu_work(); - -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); - free_all_tasks(); -out1: - free_cpumask_var(marked_cpus); - goto out; -} - - -void sync_stop(void) -{ - end_cpu_work(); - 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); - barrier(); /* do all of the above first */ - - flush_cpu_work(); - - free_all_tasks(); - free_cpumask_var(marked_cpus); -} - - -/* 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(const struct path *path) -{ - unsigned long cookie; - - if (path->dentry->d_flags & DCACHE_COOKIE) - return (unsigned long)path->dentry; - get_dcookie(path, &cookie); - return cookie; -} - - -/* Look up the dcookie for the task's mm->exe_file, - * 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 file *exe_file; - - if (!mm) - goto done; - - exe_file = get_mm_exe_file(mm); - if (!exe_file) - goto done; - - cookie = fast_get_dcookie(&exe_file->f_path); - fput(exe_file); -done: - 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. - * - * The caller must ensure the mm is not nil (ie: not a kernel thread). - */ -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; - - mmap_read_lock(mm); - 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; - mmap_read_unlock(mm); - - 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_data(struct op_entry *entry, struct mm_struct *mm) -{ - unsigned long code, pc, val; - unsigned long cookie; - off_t offset; - - if (!op_cpu_buffer_get_data(entry, &code)) - return; - if (!op_cpu_buffer_get_data(entry, &pc)) - return; - if (!op_cpu_buffer_get_size(entry)) - return; - - if (mm) { - cookie = lookup_dcookie(mm, pc, &offset); - - if (cookie == NO_COOKIE) - offset = pc; - if (cookie == INVALID_COOKIE) { - atomic_inc(&oprofile_stats.sample_lost_no_mapping); - offset = pc; - } - if (cookie != last_cookie) { - add_cookie_switch(cookie); - last_cookie = cookie; - } - } else - offset = pc; - - add_event_entry(ESCAPE_CODE); - add_event_entry(code); - add_event_entry(offset); /* Offset from Dcookie */ - - while (op_cpu_buffer_get_data(entry, &val)) - add_event_entry(val); -} - -static inline void add_sample_entry(unsigned long offset, unsigned long event) -{ - add_event_entry(offset); - add_event_entry(event); -} - - -/* - * 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. Return 0 on failure. - */ -static int -add_sample(struct mm_struct *mm, struct op_sample *s, int in_kernel) -{ - unsigned long cookie; - off_t offset; - - if (in_kernel) { - add_sample_entry(s->eip, s->event); - return 1; - } - - /* add userspace sample */ - - if (!mm) { - atomic_inc(&oprofile_stats.sample_lost_no_mm); - return 0; - } - - 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; -} - - -static void release_mm(struct mm_struct *mm) -{ - if (!mm) - return; - mmput(mm); -} - -static inline int is_code(unsigned long val) -{ - return val == ESCAPE_CODE; -} - - -/* 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; - - cpumask_set_cpu(cpu, marked_cpus); - - for_each_online_cpu(i) { - if (!cpumask_test_cpu(i, marked_cpus)) - return; - } - - /* All CPUs have been processed at least once, - * we can process the mortuary once - */ - process_task_mortuary(); - - cpumask_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_lock and doing - * lookup in task->mm->mmap to convert EIP into dcookie/offset - * value. - */ -void sync_buffer(int cpu) -{ - struct mm_struct *mm = NULL; - struct mm_struct *oldmm; - unsigned long val; - struct task_struct *new; - unsigned long cookie = 0; - int in_kernel = 1; - sync_buffer_state state = sb_buffer_start; - unsigned int i; - unsigned long available; - unsigned long flags; - struct op_entry entry; - struct op_sample *sample; - - mutex_lock(&buffer_mutex); - - add_cpu_switch(cpu); - - op_cpu_buffer_reset(cpu); - available = op_cpu_buffer_entries(cpu); - - for (i = 0; i < available; ++i) { - sample = op_cpu_buffer_read_entry(&entry, cpu); - if (!sample) - break; - - if (is_code(sample->eip)) { - flags = sample->event; - if (flags & TRACE_BEGIN) { - state = sb_bt_start; - add_trace_begin(); - } - if (flags & KERNEL_CTX_SWITCH) { - /* kernel/userspace switch */ - in_kernel = flags & IS_KERNEL; - if (state == sb_buffer_start) - state = sb_sample_start; - add_kernel_ctx_switch(flags & IS_KERNEL); - } - if (flags & USER_CTX_SWITCH - && op_cpu_buffer_get_data(&entry, &val)) { - /* userspace context switch */ - new = (struct task_struct *)val; - oldmm = mm; - release_mm(oldmm); - mm = get_task_mm(new); - if (mm != oldmm) - cookie = get_exec_dcookie(mm); - add_user_ctx_switch(new, cookie); - } - if (op_cpu_buffer_get_size(&entry)) - add_data(&entry, mm); - continue; - } - - if (state < sb_bt_start) - /* ignore sample */ - continue; - - if (add_sample(mm, sample, in_kernel)) - continue; - - /* ignore backtraces if failed to add a sample */ - if (state == sb_bt_start) { - state = sb_bt_ignore; - atomic_inc(&oprofile_stats.bt_lost_no_mapping); - } - } - release_mm(mm); - - mark_done(cpu); - - mutex_unlock(&buffer_mutex); -} - -/* The function can be used to add a buffer worth of data directly to - * the kernel buffer. The buffer is assumed to be a circular buffer. - * Take the entries from index start and end at index end, wrapping - * at max_entries. - */ -void oprofile_put_buff(unsigned long *buf, unsigned int start, - unsigned int stop, unsigned int max) -{ - int i; - - i = start; - - mutex_lock(&buffer_mutex); - while (i != stop) { - add_event_entry(buf[i++]); - - if (i >= max) - i = 0; - } - - mutex_unlock(&buffer_mutex); -} - |