[PATCH] Block queue IO tracing support (blktrace) as of 2006-03-23

Signed-off-by: Jens Axboe <axboe@suse.de>

1 files changed, 277 insertions, 0 deletions

diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h
new file mode 100644
index 000000000000..b34d3e73d5ea
--- /dev/null
+++ b/include/linux/blktrace_api.h
@@ -0,0 +1,277 @@
+#ifndef BLKTRACE_H
+#define BLKTRACE_H
+
+#include <linux/config.h>
+#include <linux/blkdev.h>
+#include <linux/relay.h>
+
+/*
+ * Trace categories
+ */
+enum blktrace_cat {
+        BLK_TC_READ     = 1 << 0,       /* reads */
+        BLK_TC_WRITE    = 1 << 1,       /* writes */
+        BLK_TC_BARRIER  = 1 << 2,       /* barrier */
+        BLK_TC_SYNC     = 1 << 3,       /* barrier */
+        BLK_TC_QUEUE    = 1 << 4,       /* queueing/merging */
+        BLK_TC_REQUEUE  = 1 << 5,       /* requeueing */
+        BLK_TC_ISSUE    = 1 << 6,       /* issue */
+        BLK_TC_COMPLETE = 1 << 7,       /* completions */
+        BLK_TC_FS       = 1 << 8,       /* fs requests */
+        BLK_TC_PC       = 1 << 9,       /* pc requests */
+        BLK_TC_NOTIFY   = 1 << 10,      /* special message */
+
+        BLK_TC_END      = 1 << 15,      /* only 16-bits, reminder */
+};
+
+#define BLK_TC_SHIFT            (16)
+#define BLK_TC_ACT(act)         ((act) << BLK_TC_SHIFT)
+
+/*
+ * Basic trace actions
+ */
+enum blktrace_act {
+        __BLK_TA_QUEUE = 1,             /* queued */
+        __BLK_TA_BACKMERGE,             /* back merged to existing rq */
+        __BLK_TA_FRONTMERGE,            /* front merge to existing rq */
+        __BLK_TA_GETRQ,                 /* allocated new request */
+        __BLK_TA_SLEEPRQ,               /* sleeping on rq allocation */
+        __BLK_TA_REQUEUE,               /* request requeued */
+        __BLK_TA_ISSUE,                 /* sent to driver */
+        __BLK_TA_COMPLETE,              /* completed by driver */
+        __BLK_TA_PLUG,                  /* queue was plugged */
+        __BLK_TA_UNPLUG_IO,             /* queue was unplugged by io */
+        __BLK_TA_UNPLUG_TIMER,          /* queue was unplugged by timer */
+        __BLK_TA_INSERT,                /* insert request */
+        __BLK_TA_SPLIT,                 /* bio was split */
+        __BLK_TA_BOUNCE,                /* bio was bounced */
+        __BLK_TA_REMAP,                 /* bio was remapped */
+};
+
+/*
+ * Trace actions in full. Additionally, read or write is masked
+ */
+#define BLK_TA_QUEUE            (__BLK_TA_QUEUE | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_BACKMERGE        (__BLK_TA_BACKMERGE | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_FRONTMERGE       (__BLK_TA_FRONTMERGE | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_GETRQ            (__BLK_TA_GETRQ | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_SLEEPRQ          (__BLK_TA_SLEEPRQ | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_REQUEUE          (__BLK_TA_REQUEUE | BLK_TC_ACT(BLK_TC_REQUEUE))
+#define BLK_TA_ISSUE            (__BLK_TA_ISSUE | BLK_TC_ACT(BLK_TC_ISSUE))
+#define BLK_TA_COMPLETE         (__BLK_TA_COMPLETE| BLK_TC_ACT(BLK_TC_COMPLETE))
+#define BLK_TA_PLUG             (__BLK_TA_PLUG | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_UNPLUG_IO        (__BLK_TA_UNPLUG_IO | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_UNPLUG_TIMER     (__BLK_TA_UNPLUG_TIMER | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_INSERT           (__BLK_TA_INSERT | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_SPLIT            (__BLK_TA_SPLIT)
+#define BLK_TA_BOUNCE           (__BLK_TA_BOUNCE)
+#define BLK_TA_REMAP            (__BLK_TA_REMAP | BLK_TC_ACT(BLK_TC_QUEUE))
+
+#define BLK_IO_TRACE_MAGIC      0x65617400
+#define BLK_IO_TRACE_VERSION    0x07
+
+/*
+ * The trace itself
+ */
+struct blk_io_trace {
+        u32 magic;              /* MAGIC << 8 | version */
+        u32 sequence;           /* event number */
+        u64 time;               /* in microseconds */
+        u64 sector;             /* disk offset */
+        u32 bytes;              /* transfer length */
+        u32 action;             /* what happened */
+        u32 pid;                /* who did it */
+        u32 device;             /* device number */
+        u32 cpu;                /* on what cpu did it happen */
+        u16 error;              /* completion error */
+        u16 pdu_len;            /* length of data after this trace */
+};
+
+/*
+ * The remap event
+ */
+struct blk_io_trace_remap {
+        u32 device;
+        u32 __pad;
+        u64 sector;
+};
+
+enum {
+        Blktrace_setup = 1,
+        Blktrace_running,
+        Blktrace_stopped,
+};
+
+struct blk_trace {
+        int trace_state;
+        struct rchan *rchan;
+        unsigned long *sequence;
+        u16 act_mask;
+        u64 start_lba;
+        u64 end_lba;
+        u32 pid;
+        u32 dev;
+        struct dentry *dir;
+        struct dentry *dropped_file;
+        atomic_t dropped;
+};
+
+/*
+ * User setup structure passed with BLKTRACESTART
+ */
+struct blk_user_trace_setup {
+        char name[BDEVNAME_SIZE];       /* output */
+        u16 act_mask;                   /* input */
+        u32 buf_size;                   /* input */
+        u32 buf_nr;                     /* input */
+        u64 start_lba;
+        u64 end_lba;
+        u32 pid;
+};
+
+#if defined(CONFIG_BLK_DEV_IO_TRACE)
+extern int blk_trace_ioctl(struct block_device *, unsigned, char __user *);
+extern void blk_trace_shutdown(request_queue_t *);
+extern void __blk_add_trace(struct blk_trace *, sector_t, int, int, u32, int, int, void *);
+
+/**
+ * blk_add_trace_rq - Add a trace for a request oriented action
+ * @q:          queue the io is for
+ * @rq:         the source request
+ * @what:       the action
+ *
+ * Description:
+ *     Records an action against a request. Will log the bio offset + size.
+ *
+ **/
+static inline void blk_add_trace_rq(struct request_queue *q, struct request *rq,
+                                    u32 what)
+{
+        struct blk_trace *bt = q->blk_trace;
+        int rw = rq->flags & 0x07;
+
+        if (likely(!bt))
+                return;
+
+        if (blk_pc_request(rq)) {
+                what |= BLK_TC_ACT(BLK_TC_PC);
+                __blk_add_trace(bt, 0, rq->data_len, rw, what, rq->errors, sizeof(rq->cmd), rq->cmd);
+        } else  {
+                what |= BLK_TC_ACT(BLK_TC_FS);
+                __blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9, rw, what, rq->errors, 0, NULL);
+        }
+}
+
+/**
+ * blk_add_trace_bio - Add a trace for a bio oriented action
+ * @q:          queue the io is for
+ * @bio:        the source bio
+ * @what:       the action
+ *
+ * Description:
+ *     Records an action against a bio. Will log the bio offset + size.
+ *
+ **/
+static inline void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
+                                     u32 what)
+{
+        struct blk_trace *bt = q->blk_trace;
+
+        if (likely(!bt))
+                return;
+
+        __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what, !bio_flagged(bio, BIO_UPTODATE), 0, NULL);
+}
+
+/**
+ * blk_add_trace_generic - Add a trace for a generic action
+ * @q:          queue the io is for
+ * @bio:        the source bio
+ * @rw:         the data direction
+ * @what:       the action
+ *
+ * Description:
+ *     Records a simple trace
+ *
+ **/
+static inline void blk_add_trace_generic(struct request_queue *q,
+                                         struct bio *bio, int rw, u32 what)
+{
+        struct blk_trace *bt = q->blk_trace;
+
+        if (likely(!bt))
+                return;
+
+        if (bio)
+                blk_add_trace_bio(q, bio, what);
+        else
+                __blk_add_trace(bt, 0, 0, rw, what, 0, 0, NULL);
+}
+
+/**
+ * blk_add_trace_pdu_int - Add a trace for a bio with an integer payload
+ * @q:          queue the io is for
+ * @what:       the action
+ * @bio:        the source bio
+ * @pdu:        the integer payload
+ *
+ * Description:
+ *     Adds a trace with some integer payload. This might be an unplug
+ *     option given as the action, with the depth at unplug time given
+ *     as the payload
+ *
+ **/
+static inline void blk_add_trace_pdu_int(struct request_queue *q, u32 what,
+                                         struct bio *bio, unsigned int pdu)
+{
+        struct blk_trace *bt = q->blk_trace;
+        u64 rpdu = cpu_to_be64(pdu);
+
+        if (likely(!bt))
+                return;
+
+        if (bio)
+                __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what, !bio_flagged(bio, BIO_UPTODATE), sizeof(rpdu), &rpdu);
+        else
+                __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
+}
+
+/**
+ * blk_add_trace_remap - Add a trace for a remap operation
+ * @q:          queue the io is for
+ * @bio:        the source bio
+ * @dev:        target device
+ * @from:       source sector
+ * @to:         target sector
+ *
+ * Description:
+ *     Device mapper or raid target sometimes need to split a bio because
+ *     it spans a stripe (or similar). Add a trace for that action.
+ *
+ **/
+static inline void blk_add_trace_remap(struct request_queue *q, struct bio *bio,
+                                       dev_t dev, sector_t from, sector_t to)
+{
+        struct blk_trace *bt = q->blk_trace;
+        struct blk_io_trace_remap r;
+
+        if (likely(!bt))
+                return;
+
+        r.device = cpu_to_be32(dev);
+        r.sector = cpu_to_be64(to);
+
+        __blk_add_trace(bt, from, bio->bi_size, bio->bi_rw, BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE), sizeof(r), &r);
+}
+
+#else /* !CONFIG_BLK_DEV_IO_TRACE */
+#define blk_trace_ioctl(bdev, cmd, arg)         (-ENOTTY)
+#define blk_trace_shutdown(q)                   do { } while (0)
+#define blk_add_trace_rq(q, rq, what)           do { } while (0)
+#define blk_add_trace_bio(q, rq, what)          do { } while (0)
+#define blk_add_trace_generic(q, rq, rw, what)  do { } while (0)
+#define blk_add_trace_pdu_int(q, what, bio, pdu)        do { } while (0)
+#define blk_add_trace_remap(q, bio, dev, f, t)  do {} while (0)
+#endif /* CONFIG_BLK_DEV_IO_TRACE */
+
+#endif