The ftrace daemon is complex and error prone. This patch strips it out of the code. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 280 ++++-------------------------------------- kernel/trace/trace_selftest.c | 14 -- 2 files changed, 28 insertions(+), 266 deletions(-) Index: linux-compile.git/kernel/trace/ftrace.c =================================================================== --- linux-compile.git.orig/kernel/trace/ftrace.c 2008-10-22 16:07:29.000000000 -0400 +++ linux-compile.git/kernel/trace/ftrace.c 2008-10-22 16:07:36.000000000 -0400 @@ -165,21 +165,8 @@ static int __unregister_ftrace_function( } #ifdef CONFIG_DYNAMIC_FTRACE - #ifndef CONFIG_FTRACE_MCOUNT_RECORD -/* - * The hash lock is only needed when the recording of the mcount - * callers are dynamic. That is, by the caller themselves and - * not recorded via the compilation. - */ -static DEFINE_SPINLOCK(ftrace_hash_lock); -#define ftrace_hash_lock(flags) spin_lock_irqsave(&ftrace_hash_lock, flags) -#define ftrace_hash_unlock(flags) \ - spin_unlock_irqrestore(&ftrace_hash_lock, flags) -#else -/* This is protected via the ftrace_lock with MCOUNT_RECORD. */ -#define ftrace_hash_lock(flags) do { (void)(flags); } while (0) -#define ftrace_hash_unlock(flags) do { } while(0) +# error Dynamic ftrace depends on MCOUNT_RECORD #endif /* @@ -190,8 +177,6 @@ static DEFINE_SPINLOCK(ftrace_hash_lock) */ static unsigned long mcount_addr = MCOUNT_ADDR; -static struct task_struct *ftraced_task; - enum { FTRACE_ENABLE_CALLS = (1 << 0), FTRACE_DISABLE_CALLS = (1 << 1), @@ -208,7 +193,6 @@ static struct hlist_head ftrace_hash[FTR static DEFINE_PER_CPU(int, ftrace_shutdown_disable_cpu); -static DEFINE_MUTEX(ftraced_lock); static DEFINE_MUTEX(ftrace_regex_lock); struct ftrace_page { @@ -226,10 +210,6 @@ struct ftrace_page { static struct ftrace_page *ftrace_pages_start; static struct ftrace_page *ftrace_pages; -static int ftraced_trigger; -static int ftraced_suspend; -static int ftraced_stop; - static int ftrace_record_suspend; static struct dyn_ftrace *ftrace_free_records; @@ -393,7 +373,6 @@ static void ftrace_record_ip(unsigned long ip) { struct dyn_ftrace *node; - unsigned long flags; unsigned long key; int resched; int cpu; @@ -425,24 +404,18 @@ ftrace_record_ip(unsigned long ip) if (ftrace_ip_in_hash(ip, key)) goto out; - ftrace_hash_lock(flags); - /* This ip may have hit the hash before the lock */ if (ftrace_ip_in_hash(ip, key)) - goto out_unlock; + goto out; node = ftrace_alloc_dyn_node(ip); if (!node) - goto out_unlock; + goto out; node->ip = ip; ftrace_add_hash(node, key); - ftraced_trigger = 1; - - out_unlock: - ftrace_hash_unlock(flags); out: per_cpu(ftrace_shutdown_disable_cpu, cpu)--; @@ -642,7 +615,7 @@ ftrace_code_disable(struct dyn_ftrace *r return 1; } -static int __ftrace_update_code(void *ignore); +static int ftrace_update_code(void *ignore); static int __ftrace_modify_code(void *data) { @@ -654,7 +627,7 @@ static int __ftrace_modify_code(void *da * Update any recorded ips now that we have the * machine stopped */ - __ftrace_update_code(NULL); + ftrace_update_code(NULL); ftrace_replace_code(1); tracing_on = 1; } else if (*command & FTRACE_DISABLE_CALLS) { @@ -681,26 +654,9 @@ static void ftrace_run_update_code(int c stop_machine(__ftrace_modify_code, &command, NULL); } -void ftrace_disable_daemon(void) -{ - /* Stop the daemon from calling kstop_machine */ - mutex_lock(&ftraced_lock); - ftraced_stop = 1; - mutex_unlock(&ftraced_lock); - - ftrace_force_update(); -} - -void ftrace_enable_daemon(void) -{ - mutex_lock(&ftraced_lock); - ftraced_stop = 0; - mutex_unlock(&ftraced_lock); - - ftrace_force_update(); -} - static ftrace_func_t saved_ftrace_func; +static int ftrace_start; +static DEFINE_MUTEX(ftrace_start_lock); static void ftrace_startup(void) { @@ -709,9 +665,9 @@ static void ftrace_startup(void) if (unlikely(ftrace_disabled)) return; - mutex_lock(&ftraced_lock); - ftraced_suspend++; - if (ftraced_suspend == 1) + mutex_lock(&ftrace_start_lock); + ftrace_start++; + if (ftrace_start == 1) command |= FTRACE_ENABLE_CALLS; if (saved_ftrace_func != ftrace_trace_function) { @@ -724,7 +680,7 @@ static void ftrace_startup(void) ftrace_run_update_code(command); out: - mutex_unlock(&ftraced_lock); + mutex_unlock(&ftrace_start_lock); } static void ftrace_shutdown(void) @@ -734,9 +690,9 @@ static void ftrace_shutdown(void) if (unlikely(ftrace_disabled)) return; - mutex_lock(&ftraced_lock); - ftraced_suspend--; - if (!ftraced_suspend) + mutex_lock(&ftrace_start_lock); + ftrace_start--; + if (!ftrace_start) command |= FTRACE_DISABLE_CALLS; if (saved_ftrace_func != ftrace_trace_function) { @@ -749,7 +705,7 @@ static void ftrace_shutdown(void) ftrace_run_update_code(command); out: - mutex_unlock(&ftraced_lock); + mutex_unlock(&ftrace_start_lock); } static void ftrace_startup_sysctl(void) @@ -759,15 +715,15 @@ static void ftrace_startup_sysctl(void) if (unlikely(ftrace_disabled)) return; - mutex_lock(&ftraced_lock); + mutex_lock(&ftrace_start_lock); /* Force update next time */ saved_ftrace_func = NULL; - /* ftraced_suspend is true if we want ftrace running */ - if (ftraced_suspend) + /* ftrace_start is true if we want ftrace running */ + if (ftrace_start) command |= FTRACE_ENABLE_CALLS; ftrace_run_update_code(command); - mutex_unlock(&ftraced_lock); + mutex_unlock(&ftrace_start_lock); } static void ftrace_shutdown_sysctl(void) @@ -777,20 +733,20 @@ static void ftrace_shutdown_sysctl(void) if (unlikely(ftrace_disabled)) return; - mutex_lock(&ftraced_lock); - /* ftraced_suspend is true if ftrace is running */ - if (ftraced_suspend) + mutex_lock(&ftrace_start_lock); + /* ftrace_start is true if ftrace is running */ + if (ftrace_start) command |= FTRACE_DISABLE_CALLS; ftrace_run_update_code(command); - mutex_unlock(&ftraced_lock); + mutex_unlock(&ftrace_start_lock); } static cycle_t ftrace_update_time; static unsigned long ftrace_update_cnt; unsigned long ftrace_update_tot_cnt; -static int __ftrace_update_code(void *ignore) +static int ftrace_update_code(void *ignore) { int i, save_ftrace_enabled; cycle_t start, stop; @@ -864,7 +820,6 @@ static int __ftrace_update_code(void *ig stop = ftrace_now(raw_smp_processor_id()); ftrace_update_time = stop - start; ftrace_update_tot_cnt += ftrace_update_cnt; - ftraced_trigger = 0; ftrace_enabled = save_ftrace_enabled; ftrace_record_suspend--; @@ -872,17 +827,6 @@ static int __ftrace_update_code(void *ig return 0; } -static int ftrace_update_code(void) -{ - if (unlikely(ftrace_disabled) || - !ftrace_enabled || !ftraced_trigger) - return 0; - - stop_machine(__ftrace_update_code, NULL, NULL); - - return 1; -} - static int __init ftrace_dyn_table_alloc(unsigned long num_to_init) { struct ftrace_page *pg; @@ -1420,10 +1364,10 @@ ftrace_regex_release(struct inode *inode } mutex_lock(&ftrace_sysctl_lock); - mutex_lock(&ftraced_lock); - if (iter->filtered && ftraced_suspend && ftrace_enabled) + mutex_lock(&ftrace_start_lock); + if (iter->filtered && ftrace_start && ftrace_enabled) ftrace_run_update_code(FTRACE_ENABLE_CALLS); - mutex_unlock(&ftraced_lock); + mutex_unlock(&ftrace_start_lock); mutex_unlock(&ftrace_sysctl_lock); kfree(iter); @@ -1443,55 +1387,6 @@ ftrace_notrace_release(struct inode *ino return ftrace_regex_release(inode, file, 0); } -static ssize_t -ftraced_read(struct file *filp, char __user *ubuf, - size_t cnt, loff_t *ppos) -{ - /* don't worry about races */ - char *buf = ftraced_stop ? "disabled\n" : "enabled\n"; - int r = strlen(buf); - - return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); -} - -static ssize_t -ftraced_write(struct file *filp, const char __user *ubuf, - size_t cnt, loff_t *ppos) -{ - char buf[64]; - long val; - int ret; - - if (cnt >= sizeof(buf)) - return -EINVAL; - - if (copy_from_user(&buf, ubuf, cnt)) - return -EFAULT; - - if (strncmp(buf, "enable", 6) == 0) - val = 1; - else if (strncmp(buf, "disable", 7) == 0) - val = 0; - else { - buf[cnt] = 0; - - ret = strict_strtoul(buf, 10, &val); - if (ret < 0) - return ret; - - val = !!val; - } - - if (val) - ftrace_enable_daemon(); - else - ftrace_disable_daemon(); - - filp->f_pos += cnt; - - return cnt; -} - static struct file_operations ftrace_avail_fops = { .open = ftrace_avail_open, .read = seq_read, @@ -1522,38 +1417,6 @@ static struct file_operations ftrace_not .release = ftrace_notrace_release, }; -static struct file_operations ftraced_fops = { - .open = tracing_open_generic, - .read = ftraced_read, - .write = ftraced_write, -}; - -/** - * ftrace_force_update - force an update to all recording ftrace functions - */ -int ftrace_force_update(void) -{ - int ret = 0; - - if (unlikely(ftrace_disabled)) - return -ENODEV; - - mutex_lock(&ftrace_sysctl_lock); - mutex_lock(&ftraced_lock); - - /* - * If ftraced_trigger is not set, then there is nothing - * to update. - */ - if (ftraced_trigger && !ftrace_update_code()) - ret = -EBUSY; - - mutex_unlock(&ftraced_lock); - mutex_unlock(&ftrace_sysctl_lock); - - return ret; -} - static __init int ftrace_init_debugfs(void) { struct dentry *d_tracer; @@ -1584,17 +1447,11 @@ static __init int ftrace_init_debugfs(vo pr_warning("Could not create debugfs " "'set_ftrace_notrace' entry\n"); - entry = debugfs_create_file("ftraced_enabled", 0644, d_tracer, - NULL, &ftraced_fops); - if (!entry) - pr_warning("Could not create debugfs " - "'ftraced_enabled' entry\n"); return 0; } fs_initcall(ftrace_init_debugfs); -#ifdef CONFIG_FTRACE_MCOUNT_RECORD static int ftrace_convert_nops(unsigned long *start, unsigned long *end) { @@ -1614,7 +1471,7 @@ static int ftrace_convert_nops(unsigned /* p is ignored */ local_irq_save(flags); - __ftrace_update_code(p); + ftrace_update_code(p); local_irq_restore(flags); return 0; @@ -1661,84 +1518,6 @@ void __init ftrace_init(void) failed: ftrace_disabled = 1; } -#else /* CONFIG_FTRACE_MCOUNT_RECORD */ -static int ftraced(void *ignore) -{ - unsigned long usecs; - - while (!kthread_should_stop()) { - - set_current_state(TASK_INTERRUPTIBLE); - - /* check once a second */ - schedule_timeout(HZ); - - if (unlikely(ftrace_disabled)) - continue; - - mutex_lock(&ftrace_sysctl_lock); - mutex_lock(&ftraced_lock); - if (!ftraced_suspend && !ftraced_stop && - ftrace_update_code()) { - usecs = nsecs_to_usecs(ftrace_update_time); - if (ftrace_update_tot_cnt > 100000) { - ftrace_update_tot_cnt = 0; - pr_info("hm, dftrace overflow: %lu change%s" - " (%lu total) in %lu usec%s\n", - ftrace_update_cnt, - ftrace_update_cnt != 1 ? "s" : "", - ftrace_update_tot_cnt, - usecs, usecs != 1 ? "s" : ""); - FTRACE_WARN_ON_ONCE(1); - } - } - mutex_unlock(&ftraced_lock); - mutex_unlock(&ftrace_sysctl_lock); - - ftrace_shutdown_replenish(); - } - __set_current_state(TASK_RUNNING); - return 0; -} - -static int __init ftrace_dynamic_init(void) -{ - struct task_struct *p; - unsigned long addr; - int ret; - - addr = (unsigned long)ftrace_record_ip; - - stop_machine(ftrace_dyn_arch_init, &addr, NULL); - - /* ftrace_dyn_arch_init places the return code in addr */ - if (addr) { - ret = (int)addr; - goto failed; - } - - ret = ftrace_dyn_table_alloc(NR_TO_INIT); - if (ret) - goto failed; - - p = kthread_run(ftraced, NULL, "ftraced"); - if (IS_ERR(p)) { - ret = -1; - goto failed; - } - - last_ftrace_enabled = ftrace_enabled = 1; - ftraced_task = p; - - return 0; - - failed: - ftrace_disabled = 1; - return ret; -} - -core_initcall(ftrace_dynamic_init); -#endif /* CONFIG_FTRACE_MCOUNT_RECORD */ #else # define ftrace_startup() do { } while (0) @@ -1758,9 +1537,6 @@ void ftrace_kill(void) { ftrace_disabled = 1; ftrace_enabled = 0; -#ifdef CONFIG_DYNAMIC_FTRACE - ftraced_suspend = -1; -#endif clear_ftrace_function(); } Index: linux-compile.git/kernel/trace/trace_selftest.c =================================================================== --- linux-compile.git.orig/kernel/trace/trace_selftest.c 2008-10-22 15:09:03.000000000 -0400 +++ linux-compile.git/kernel/trace/trace_selftest.c 2008-10-22 16:07:36.000000000 -0400 @@ -99,13 +99,6 @@ int trace_selftest_startup_dynamic_traci /* passed in by parameter to fool gcc from optimizing */ func(); - /* update the records */ - ret = ftrace_force_update(); - if (ret) { - printk(KERN_CONT ".. ftraced failed .. "); - return ret; - } - /* * Some archs *cough*PowerPC*cough* add charachters to the * start of the function names. We simply put a '*' to @@ -183,13 +176,6 @@ trace_selftest_startup_function(struct t /* make sure msleep has been recorded */ msleep(1); - /* force the recorded functions to be traced */ - ret = ftrace_force_update(); - if (ret) { - printk(KERN_CONT ".. ftraced failed .. "); - return ret; - } - /* start the tracing */ ftrace_enabled = 1; tracer_enabled = 1; -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/