/** * @file buffer_sync.c * * @remark Copyright 2002 OProfile authors * @remark Read the file COPYING * * @author John Levon <levon@movementarian.org> * @author Barry Kasindorf * * 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 inttask_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 inttask_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 intmunmap_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 intmodule_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 longlookup_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 void increment_tail(struct oprofile_cpu_buffer *b){ unsigned long new_tail = b->tail_pos + 1; rmb(); /* be sure fifo pointers are synchromized */ if (new_tail < b->buffer_size) b->tail_pos = new_tail; else b->tail_pos = 0;} 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 voidadd_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);} #ifdef CONFIG_OPROFILE_IBS #define IBS_FETCH_CODE_SIZE 2#define IBS_OP_CODE_SIZE 5#define IBS_EIP(offset) \ (((struct op_sample *)&cpu_buf->buffer[(offset)])->eip)#define IBS_EVENT(offset) \ (((struct op_sample *)&cpu_buf->buffer[(offset)])->event) /* * Add IBS fetch and op entries to event buffer */static void add_ibs_begin(struct oprofile_cpu_buffer *cpu_buf, int code, struct mm_struct *mm){ unsigned long rip; int i, count; unsigned long ibs_cookie = 0; off_t offset; increment_tail(cpu_buf); /* move to RIP entry */ rip = IBS_EIP(cpu_buf->tail_pos); #ifdef __LP64__ rip += IBS_EVENT(cpu_buf->tail_pos) << 32;#endif if (mm) { ibs_cookie = lookup_dcookie(mm, rip, &offset); if (ibs_cookie == NO_COOKIE) offset = rip; if (ibs_cookie == INVALID_COOKIE) { atomic_inc(&oprofile_stats.sample_lost_no_mapping); offset = rip; } if (ibs_cookie != last_cookie) { add_cookie_switch(ibs_cookie); last_cookie = ibs_cookie; } } else offset = rip; add_event_entry(ESCAPE_CODE); add_event_entry(code); add_event_entry(offset); /* Offset from Dcookie */ /* we send the Dcookie offset, but send the raw Linear Add also*/ add_event_entry(IBS_EIP(cpu_buf->tail_pos)); add_event_entry(IBS_EVENT(cpu_buf->tail_pos)); if (code == IBS_FETCH_CODE) count = IBS_FETCH_CODE_SIZE; /*IBS FETCH is 2 int64s*/ else count = IBS_OP_CODE_SIZE; /*IBS OP is 5 int64s*/ for (i = 0; i < count; i++) { increment_tail(cpu_buf); add_event_entry(IBS_EIP(cpu_buf->tail_pos)); add_event_entry(IBS_EVENT(cpu_buf->tail_pos)); }} #endif 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 intadd_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);} /* 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.Lines 1–500 of 657. Load more
/** * @file buffer_sync.c * * @remark Copyright 2002 OProfile authors * @remark Read the file COPYING * * @author John Levon <levon@movementarian.org> * @author Barry Kasindorf * * 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 void increment_tail(struct oprofile_cpu_buffer *b) { unsigned long new_tail = b->tail_pos + 1; rmb(); /* be sure fifo pointers are synchromized */ if (new_tail < b->buffer_size) b->tail_pos = new_tail; else b->tail_pos = 0; } 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); } #ifdef CONFIG_OPROFILE_IBS #define IBS_FETCH_CODE_SIZE 2 #define IBS_OP_CODE_SIZE 5 #define IBS_EIP(offset) \ (((struct op_sample *)&cpu_buf->buffer[(offset)])->eip) #define IBS_EVENT(offset) \ (((struct op_sample *)&cpu_buf->buffer[(offset)])->event) /* * Add IBS fetch and op entries to event buffer */ static void add_ibs_begin(struct oprofile_cpu_buffer *cpu_buf, int code, struct mm_struct *mm) { unsigned long rip; int i, count; unsigned long ibs_cookie = 0; off_t offset; increment_tail(cpu_buf); /* move to RIP entry */ rip = IBS_EIP(cpu_buf->tail_pos); #ifdef __LP64__ rip += IBS_EVENT(cpu_buf->tail_pos) << 32; #endif if (mm) { ibs_cookie = lookup_dcookie(mm, rip, &offset); if (ibs_cookie == NO_COOKIE) offset = rip; if (ibs_cookie == INVALID_COOKIE) { atomic_inc(&oprofile_stats.sample_lost_no_mapping); offset = rip; } if (ibs_cookie != last_cookie) { add_cookie_switch(ibs_cookie); last_cookie = ibs_cookie; } } else offset = rip; add_event_entry(ESCAPE_CODE); add_event_entry(code); add_event_entry(offset); /* Offset from Dcookie */ /* we send the Dcookie offset, but send the raw Linear Add also*/ add_event_entry(IBS_EIP(cpu_buf->tail_pos)); add_event_entry(IBS_EVENT(cpu_buf->tail_pos)); if (code == IBS_FETCH_CODE) count = IBS_FETCH_CODE_SIZE; /*IBS FETCH is 2 int64s*/ else count = IBS_OP_CODE_SIZE; /*IBS OP is 5 int64s*/ for (i = 0; i < count; i++) { increment_tail(cpu_buf); add_event_entry(IBS_EIP(cpu_buf->tail_pos)); add_event_entry(IBS_EVENT(cpu_buf->tail_pos)); } } #endif 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); } /* 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.