crc32c.h « linux « include - linux-yocto - Yocto Linux Embedded kernel

> -EINVAL; switch (type) { case PROFILE_TASK_EXIT: err = blocking_notifier_chain_unregister( &task_exit_notifier, n); break; case PROFILE_MUNMAP: err = blocking_notifier_chain_unregister( &munmap_notifier, n); break; } return err; } EXPORT_SYMBOL_GPL(profile_event_unregister); #ifdef CONFIG_SMP /* * Each cpu has a pair of open-addressed hashtables for pending * profile hits. read_profile() IPI's all cpus to request them * to flip buffers and flushes their contents to prof_buffer itself. * Flip requests are serialized by the profile_flip_mutex. The sole * use of having a second hashtable is for avoiding cacheline * contention that would otherwise happen during flushes of pending * profile hits required for the accuracy of reported profile hits * and so resurrect the interrupt livelock issue. * * The open-addressed hashtables are indexed by profile buffer slot * and hold the number of pending hits to that profile buffer slot on * a cpu in an entry. When the hashtable overflows, all pending hits * are accounted to their corresponding profile buffer slots with * atomic_add() and the hashtable emptied. As numerous pending hits * may be accounted to a profile buffer slot in a hashtable entry, * this amortizes a number of atomic profile buffer increments likely * to be far larger than the number of entries in the hashtable, * particularly given that the number of distinct profile buffer * positions to which hits are accounted during short intervals (e.g. * several seconds) is usually very small. Exclusion from buffer * flipping is provided by interrupt disablement (note that for * SCHED_PROFILING or SLEEP_PROFILING profile_hit() may be called from * process context). * The hash function is meant to be lightweight as opposed to strong, * and was vaguely inspired by ppc64 firmware-supported inverted * pagetable hash functions, but uses a full hashtable full of finite * collision chains, not just pairs of them. * * -- nyc */ static void __profile_flip_buffers(void *unused) { int cpu = smp_processor_id(); per_cpu(cpu_profile_flip, cpu) = !per_cpu(cpu_profile_flip, cpu); } static void profile_flip_buffers(void) { int i, j, cpu; mutex_lock(&profile_flip_mutex); j = per_cpu(cpu_profile_flip, get_cpu()); put_cpu(); on_each_cpu(__profile_flip_buffers, NULL, 1); for_each_online_cpu(cpu) { struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[j]; for (i = 0; i < NR_PROFILE_HIT; ++i) { if (!hits[i].hits) { if (hits[i].pc) hits[i].pc = 0; continue; } atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]); hits[i].hits = hits[i].pc = 0; } } mutex_unlock(&profile_flip_mutex); } static void profile_discard_flip_buffers(void) { int i, cpu; mutex_lock(&profile_flip_mutex); i = per_cpu(cpu_profile_flip, get_cpu()); put_cpu(); on_each_cpu(__profile_flip_buffers, NULL, 1); for_each_online_cpu(cpu) { struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[i]; memset(hits, 0, NR_PROFILE_HIT*sizeof(struct profile_hit)); } mutex_unlock(&profile_flip_mutex); } static void do_profile_hits(int type, void *__pc, unsigned int nr_hits) { unsigned long primary, secondary, flags, pc = (unsigned long)__pc; int i, j, cpu; struct profile_hit *hits; pc = min((pc - (unsigned long)_stext) >> prof_shift, prof_len - 1); i = primary = (pc & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT; secondary = (~(pc << 1) & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT; cpu = get_cpu(); hits = per_cpu(cpu_profile_hits, cpu)[per_cpu(cpu_profile_flip, cpu)]; if (!hits) { put_cpu(); return; } /* * We buffer the global profiler buffer into a per-CPU * queue and thus reduce the number of global (and possibly * NUMA-alien) accesses. The write-queue is self-coalescing: */ local_irq_save(flags); do { for (j = 0; j < PROFILE_GRPSZ; ++j) { if (hits[i + j].pc == pc) { hits[i + j].hits += nr_hits; goto out; } else if (!hits[i + j].hits) { hits[i + j].pc = pc; hits[i + j].hits = nr_hits; goto out; } } i = (i + secondary) & (NR_PROFILE_HIT - 1); } while (i != primary); /* * Add the current hit(s) and flush the write-queue out * to the global buffer: */ atomic_add(nr_hits, &prof_buffer[pc]); for (i = 0; i < NR_PROFILE_HIT; ++i) { atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]); hits[i].pc = hits[i].hits = 0; } out: local_irq_restore(flags); put_cpu(); } static int profile_cpu_callback(struct notifier_block *info, unsigned long action, void *__cpu) { int node, cpu = (unsigned long)__cpu; struct page *page; switch (action) { case CPU_UP_PREPARE: case CPU_UP_PREPARE_FROZEN: node = cpu_to_mem(cpu); per_cpu(cpu_profile_flip, cpu) = 0; if (!per_cpu(cpu_profile_hits, cpu)[1]) { page = __alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0); if (!page) return notifier_from_errno(-ENOMEM); per_cpu(cpu_profile_hits, cpu)[1] = page_address(page); } if (!per_cpu(cpu_profile_hits, cpu)[0]) { page = __alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0); if (!page) goto out_free; per_cpu(cpu_profile_hits, cpu)[0] = page_address(page); } break; out_free: page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]); per_cpu(cpu_profile_hits, cpu)[1] = NULL; __free_page(page); return notifier_from_errno(-ENOMEM); case CPU_ONLINE: case CPU_ONLINE_FROZEN: if (prof_cpu_mask != NULL) cpumask_set_cpu(cpu, prof_cpu_mask); break; case CPU_UP_CANCELED: case CPU_UP_CANCELED_FROZEN: case CPU_DEAD: case CPU_DEAD_FROZEN: if (prof_cpu_mask != NULL) cpumask_clear_cpu(cpu, prof_cpu_mask); if (per_cpu(cpu_profile_hits, cpu)[0]) { page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]); per_cpu(cpu_profile_hits, cpu)[0] = NULL; __free_page(page); } if (per_cpu(cpu_profile_hits, cpu)[1]) { page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]); per_cpu(cpu_profile_hits, cpu)[1] = NULL; __free_page(page); } break; } return NOTIFY_OK; } #else /* !CONFIG_SMP */ #define profile_flip_buffers() do { } while (0) #define profile_discard_flip_buffers() do { } while (0) #define profile_cpu_callback NULL static void do_profile_hits(int type, void *__pc, unsigned int nr_hits) { unsigned long pc; pc = ((unsigned long)__pc - (unsigned long)_stext) >> prof_shift; atomic_add(nr_hits, &prof_buffer[min(pc, prof_len - 1)]); } #endif /* !CONFIG_SMP */ void profile_hits(int type, void *__pc, unsigned int nr_hits) { if (prof_on != type || !prof_buffer) return; do_profile_hits(type, __pc, nr_hits); } EXPORT_SYMBOL_GPL(profile_hits); void profile_tick(int type) { struct pt_regs *regs = get_irq_regs(); if (!user_mode(regs) && prof_cpu_mask != NULL && cpumask_test_cpu(smp_processor_id(), prof_cpu_mask)) profile_hit(type, (void *)profile_pc(regs)); } #ifdef CONFIG_PROC_FS #include <linux/proc_fs.h> #include <linux/seq_file.h> #include <asm/uaccess.h> static int prof_cpu_mask_proc_show(struct seq_file *m, void *v) { seq_printf(m, "%*pb\n", cpumask_pr_args(prof_cpu_mask)); return 0; } static int prof_cpu_mask_proc_open(struct inode *inode, struct file *file) { return single_open(file, prof_cpu_mask_proc_show, NULL); } static ssize_t prof_cpu_mask_proc_write(struct file *file, const char __user *buffer, size_t count, loff_t *pos) { cpumask_var_t new_value; int err; if (!alloc_cpumask_var(&new_value, GFP_KERNEL)) return -ENOMEM; err = cpumask_parse_user(buffer, count, new_value); if (!err) { cpumask_copy(prof_cpu_mask, new_value); err = count; } free_cpumask_var(new_value); return err; } static const struct file_operations prof_cpu_mask_proc_fops = { .open = prof_cpu_mask_proc_open, .read = seq_read, .llseek = seq_lseek, .release = single_release, .write = prof_cpu_mask_proc_write, }; void create_prof_cpu_mask(void) { /* create /proc/irq/prof_cpu_mask */ proc_create("irq/prof_cpu_mask", 0600, NULL, &prof_cpu_mask_proc_fops); } /* * This function accesses profiling information. The returned data is * binary: the sampling step and the actual contents of the profile * buffer. Use of the program readprofile is recommended in order to * get meaningful info out of these data. */ static ssize_t read_profile(struct file *file, char __user *buf, size_t count, loff_t *ppos) { unsigned long p = *ppos; ssize_t read; char *pnt; unsigned int sample_step = 1 << prof_shift; profile_flip_buffers(); if (p >= (prof_len+1)*sizeof(unsigned int)) return 0; if (count > (prof_len+1)*sizeof(unsigned int) - p) count = (prof_len+1)*sizeof(unsigned int) - p; read = 0; while (p < sizeof(unsigned int) && count > 0) { if (put_user(*((char *)(&sample_step)+p), buf)) return -EFAULT; buf++; p++; count--; read++; } pnt = (char *)prof_buffer + p - sizeof(atomic_t); if (copy_to_user(buf, (void *)pnt, count)) return -EFAULT; read += count; *ppos += read; return read; } /* * Writing to /proc/profile resets the counters * * Writing a 'profiling multiplier' value into it also re-sets the profiling * interrupt frequency, on architectures that support this. */ static ssize_t write_profile(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { #ifdef CONFIG_SMP extern int setup_profiling_timer(unsigned int multiplier); if (count == sizeof(int)) { unsigned int multiplier; if (copy_from_user(&multiplier, buf, sizeof(int))) return -EFAULT; if (setup_profiling_timer(multiplier)) return -EINVAL; } #endif profile_discard_flip_buffers(); memset(prof_buffer, 0, prof_len * sizeof(atomic_t)); return count; } static const struct file_operations proc_profile_operations = { .read = read_profile, .write = write_profile, .llseek = default_llseek, }; #ifdef CONFIG_SMP static void profile_nop(void *unused) { } static int create_hash_tables(void) { int cpu; for_each_online_cpu(cpu) { int node = cpu_to_mem(cpu); struct page *page; page = __alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE, 0); if (!page) goto out_cleanup; per_cpu(cpu_profile_hits, cpu)[1] = (struct profile_hit *)page_address(page); page = __alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE, 0); if (!page) goto out_cleanup; per_cpu(cpu_profile_hits, cpu)[0] = (struct profile_hit *)page_address(page); } return 0; out_cleanup: prof_on = 0; smp_mb(); on_each_cpu(profile_nop, NULL, 1); for_each_online_cpu(cpu) { struct page *page; if (per_cpu(cpu_profile_hits, cpu)[0]) { page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]); per_cpu(cpu_profile_hits, cpu)[0] = NULL; __free_page(page); } if (per_cpu(cpu_profile_hits, cpu)[1]) { page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]); per_cpu(cpu_profile_hits, cpu)[1] = NULL; __free_page(page); } } return -1; } #else #define create_hash_tables() ({ 0; }) #endif int __ref create_proc_profile(void) /* false positive from hotcpu_notifier */ { struct proc_dir_entry *entry; int err = 0; if (!prof_on) return 0; cpu_notifier_register_begin(); if (create_hash_tables()) { err = -ENOMEM; goto out; } entry = proc_create("profile", S_IWUSR | S_IRUGO, NULL, &proc_profile_operations); if (!entry) goto out; proc_set_size(entry, (1 + prof_len) * sizeof(atomic_t)); __hotcpu_notifier(profile_cpu_callback, 0); out: cpu_notifier_register_done(); return err; } subsys_initcall(create_proc_profile); #endif /* CONFIG_PROC_FS */