X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=block%2Fblktrace.c;h=85049a7e7a179a97c283eb4ebe6c1fe7285f80cf;hb=c26156b2534c75bb3cdedf76f6ad1340971cf5bd;hp=775471ef84a536159da907711070e889659984e2;hpb=171044d449611c6e5040b37210ff6aba47f33ee4;p=safe%2Fjmp%2Flinux-2.6 diff --git a/block/blktrace.c b/block/blktrace.c index 775471e..85049a7 100644 --- a/block/blktrace.c +++ b/block/blktrace.c @@ -25,7 +25,6 @@ #include #include -static DEFINE_PER_CPU(unsigned long long, blk_trace_cpu_offset) = { 0, }; static unsigned int blktrace_seq __read_mostly = 1; /* @@ -41,7 +40,7 @@ static void trace_note(struct blk_trace *bt, pid_t pid, int action, const int cpu = smp_processor_id(); t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; - t->time = cpu_clock(cpu) - per_cpu(blk_trace_cpu_offset, cpu); + t->time = ktime_to_ns(ktime_get()); t->device = bt->dev; t->action = action; t->pid = pid; @@ -76,6 +75,24 @@ static void trace_note_time(struct blk_trace *bt) local_irq_restore(flags); } +void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) +{ + int n; + va_list args; + unsigned long flags; + char *buf; + + local_irq_save(flags); + buf = per_cpu_ptr(bt->msg_data, smp_processor_id()); + va_start(args, fmt); + n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args); + va_end(args); + + trace_note(bt, 0, BLK_TN_MESSAGE, buf, n); + local_irq_restore(flags); +} +EXPORT_SYMBOL_GPL(__trace_note_message); + static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, pid_t pid) { @@ -94,23 +111,9 @@ static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, */ static u32 ddir_act[2] __read_mostly = { BLK_TC_ACT(BLK_TC_READ), BLK_TC_ACT(BLK_TC_WRITE) }; -/* - * Bio action bits of interest - */ -static u32 bio_act[9] __read_mostly = { 0, BLK_TC_ACT(BLK_TC_BARRIER), BLK_TC_ACT(BLK_TC_SYNC), 0, BLK_TC_ACT(BLK_TC_AHEAD), 0, 0, 0, BLK_TC_ACT(BLK_TC_META) }; - -/* - * More could be added as needed, taking care to increment the decrementer - * to get correct indexing - */ -#define trace_barrier_bit(rw) \ - (((rw) & (1 << BIO_RW_BARRIER)) >> (BIO_RW_BARRIER - 0)) -#define trace_sync_bit(rw) \ - (((rw) & (1 << BIO_RW_SYNC)) >> (BIO_RW_SYNC - 1)) -#define trace_ahead_bit(rw) \ - (((rw) & (1 << BIO_RW_AHEAD)) << (2 - BIO_RW_AHEAD)) -#define trace_meta_bit(rw) \ - (((rw) & (1 << BIO_RW_META)) >> (BIO_RW_META - 3)) +/* The ilog2() calls fall out because they're constant */ +#define MASK_TC_BIT(rw, __name) ( (rw & (1 << BIO_RW_ ## __name)) << \ + (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - BIO_RW_ ## __name) ) /* * The worker for the various blk_add_trace*() types. Fills out a @@ -130,10 +133,11 @@ void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, return; what |= ddir_act[rw & WRITE]; - what |= bio_act[trace_barrier_bit(rw)]; - what |= bio_act[trace_sync_bit(rw)]; - what |= bio_act[trace_ahead_bit(rw)]; - what |= bio_act[trace_meta_bit(rw)]; + what |= MASK_TC_BIT(rw, BARRIER); + what |= MASK_TC_BIT(rw, SYNC); + what |= MASK_TC_BIT(rw, AHEAD); + what |= MASK_TC_BIT(rw, META); + what |= MASK_TC_BIT(rw, DISCARD); pid = tsk->pid; if (unlikely(act_log_check(bt, what, sector, pid))) @@ -142,10 +146,7 @@ void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, /* * A word about the locking here - we disable interrupts to reserve * some space in the relay per-cpu buffer, to prevent an irq - * from coming in and stepping on our toes. Once reserved, it's - * enough to get preemption disabled to prevent read of this data - * before we are through filling it. get_cpu()/put_cpu() does this - * for us + * from coming in and stepping on our toes. */ local_irq_save(flags); @@ -159,7 +160,7 @@ void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; t->sequence = ++(*sequence); - t->time = cpu_clock(cpu) - per_cpu(blk_trace_cpu_offset, cpu); + t->time = ktime_to_ns(ktime_get()); t->sector = sector; t->bytes = bytes; t->action = what; @@ -179,7 +180,7 @@ void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, EXPORT_SYMBOL_GPL(__blk_add_trace); static struct dentry *blk_tree_root; -static struct mutex blk_tree_mutex; +static DEFINE_MUTEX(blk_tree_mutex); static unsigned int root_users; static inline void blk_remove_root(void) @@ -202,6 +203,7 @@ static void blk_remove_tree(struct dentry *dir) static struct dentry *blk_create_tree(const char *blk_name) { struct dentry *dir = NULL; + int created = 0; mutex_lock(&blk_tree_mutex); @@ -209,13 +211,17 @@ static struct dentry *blk_create_tree(const char *blk_name) blk_tree_root = debugfs_create_dir("block", NULL); if (!blk_tree_root) goto err; + created = 1; } dir = debugfs_create_dir(blk_name, blk_tree_root); if (dir) root_users++; - else - blk_remove_root(); + else { + /* Delete root only if we created it */ + if (created) + blk_remove_root(); + } err: mutex_unlock(&blk_tree_mutex); @@ -225,13 +231,15 @@ err: static void blk_trace_cleanup(struct blk_trace *bt) { relay_close(bt->rchan); + debugfs_remove(bt->msg_file); debugfs_remove(bt->dropped_file); blk_remove_tree(bt->dir); free_percpu(bt->sequence); + free_percpu(bt->msg_data); kfree(bt); } -static int blk_trace_remove(struct request_queue *q) +int blk_trace_remove(struct request_queue *q) { struct blk_trace *bt; @@ -245,6 +253,7 @@ static int blk_trace_remove(struct request_queue *q) return 0; } +EXPORT_SYMBOL_GPL(blk_trace_remove); static int blk_dropped_open(struct inode *inode, struct file *filp) { @@ -270,6 +279,44 @@ static const struct file_operations blk_dropped_fops = { .read = blk_dropped_read, }; +static int blk_msg_open(struct inode *inode, struct file *filp) +{ + filp->private_data = inode->i_private; + + return 0; +} + +static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, + size_t count, loff_t *ppos) +{ + char *msg; + struct blk_trace *bt; + + if (count > BLK_TN_MAX_MSG) + return -EINVAL; + + msg = kmalloc(count, GFP_KERNEL); + if (msg == NULL) + return -ENOMEM; + + if (copy_from_user(msg, buffer, count)) { + kfree(msg); + return -EFAULT; + } + + bt = filp->private_data; + __trace_note_message(bt, "%s", msg); + kfree(msg); + + return count; +} + +static const struct file_operations blk_msg_fops = { + .owner = THIS_MODULE, + .open = blk_msg_open, + .write = blk_msg_write, +}; + /* * Keep track of how many times we encountered a full subbuffer, to aid * the user space app in telling how many lost events there were. @@ -312,18 +359,18 @@ static struct rchan_callbacks blk_relay_callbacks = { /* * Setup everything required to start tracing */ -int do_blk_trace_setup(struct request_queue *q, struct block_device *bdev, +int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, struct blk_user_trace_setup *buts) { struct blk_trace *old_bt, *bt = NULL; struct dentry *dir = NULL; - char b[BDEVNAME_SIZE]; int ret, i; if (!buts->buf_size || !buts->buf_nr) return -EINVAL; - strcpy(buts->name, bdevname(bdev, b)); + strncpy(buts->name, name, BLKTRACE_BDEV_SIZE); + buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0'; /* * some device names have larger paths - convert the slashes @@ -342,13 +389,17 @@ int do_blk_trace_setup(struct request_queue *q, struct block_device *bdev, if (!bt->sequence) goto err; + bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG); + if (!bt->msg_data) + goto err; + ret = -ENOENT; dir = blk_create_tree(buts->name); if (!dir) goto err; bt->dir = dir; - bt->dev = bdev->bd_dev; + bt->dev = dev; atomic_set(&bt->dropped, 0); ret = -EIO; @@ -356,6 +407,10 @@ int do_blk_trace_setup(struct request_queue *q, struct block_device *bdev, if (!bt->dropped_file) goto err; + bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); + if (!bt->msg_file) + goto err; + bt->rchan = relay_open("trace", dir, buts->buf_size, buts->buf_nr, &blk_relay_callbacks, bt); if (!bt->rchan) @@ -385,9 +440,12 @@ err: if (dir) blk_remove_tree(dir); if (bt) { + if (bt->msg_file) + debugfs_remove(bt->msg_file); if (bt->dropped_file) debugfs_remove(bt->dropped_file); free_percpu(bt->sequence); + free_percpu(bt->msg_data); if (bt->rchan) relay_close(bt->rchan); kfree(bt); @@ -395,8 +453,8 @@ err: return ret; } -static int blk_trace_setup(struct request_queue *q, struct block_device *bdev, - char __user *arg) +int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, + char __user *arg) { struct blk_user_trace_setup buts; int ret; @@ -405,7 +463,7 @@ static int blk_trace_setup(struct request_queue *q, struct block_device *bdev, if (ret) return -EFAULT; - ret = do_blk_trace_setup(q, bdev, &buts); + ret = do_blk_trace_setup(q, name, dev, &buts); if (ret) return ret; @@ -414,8 +472,9 @@ static int blk_trace_setup(struct request_queue *q, struct block_device *bdev, return 0; } +EXPORT_SYMBOL_GPL(blk_trace_setup); -static int blk_trace_startstop(struct request_queue *q, int start) +int blk_trace_startstop(struct request_queue *q, int start) { struct blk_trace *bt; int ret; @@ -448,6 +507,7 @@ static int blk_trace_startstop(struct request_queue *q, int start) return ret; } +EXPORT_SYMBOL_GPL(blk_trace_startstop); /** * blk_trace_ioctl: - handle the ioctls associated with tracing @@ -460,6 +520,7 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) { struct request_queue *q; int ret, start = 0; + char b[BDEVNAME_SIZE]; q = bdev_get_queue(bdev); if (!q) @@ -469,7 +530,8 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) switch (cmd) { case BLKTRACESETUP: - ret = blk_trace_setup(q, bdev, arg); + bdevname(bdev, b); + ret = blk_trace_setup(q, b, bdev->bd_dev, arg); break; case BLKTRACESTART: start = 1; @@ -500,77 +562,3 @@ void blk_trace_shutdown(struct request_queue *q) blk_trace_remove(q); } } - -/* - * Average offset over two calls to cpu_clock() with a gettimeofday() - * in the middle - */ -static void blk_check_time(unsigned long long *t, int this_cpu) -{ - unsigned long long a, b; - struct timeval tv; - - a = cpu_clock(this_cpu); - do_gettimeofday(&tv); - b = cpu_clock(this_cpu); - - *t = tv.tv_sec * 1000000000 + tv.tv_usec * 1000; - *t -= (a + b) / 2; -} - -/* - * calibrate our inter-CPU timings - */ -static void blk_trace_check_cpu_time(void *data) -{ - unsigned long long *t; - int this_cpu = get_cpu(); - - t = &per_cpu(blk_trace_cpu_offset, this_cpu); - - /* - * Just call it twice, hopefully the second call will be cache hot - * and a little more precise - */ - blk_check_time(t, this_cpu); - blk_check_time(t, this_cpu); - - put_cpu(); -} - -static void blk_trace_set_ht_offsets(void) -{ -#if defined(CONFIG_SCHED_SMT) - int cpu, i; - - /* - * now make sure HT siblings have the same time offset - */ - preempt_disable(); - for_each_online_cpu(cpu) { - unsigned long long *cpu_off, *sibling_off; - - for_each_cpu_mask(i, cpu_sibling_map[cpu]) { - if (i == cpu) - continue; - - cpu_off = &per_cpu(blk_trace_cpu_offset, cpu); - sibling_off = &per_cpu(blk_trace_cpu_offset, i); - *sibling_off = *cpu_off; - } - } - preempt_enable(); -#endif -} - -static __init int blk_trace_init(void) -{ - mutex_init(&blk_tree_mutex); - on_each_cpu(blk_trace_check_cpu_time, NULL, 1, 1); - blk_trace_set_ht_offsets(); - - return 0; -} - -module_init(blk_trace_init); -