[PATCH] Block queue IO tracing support (blktrace) as of 2006-03-23
Signed-off-by: Jens Axboe <axboe@suse.de>
diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h
new file mode 100644
index 0000000..b34d3e7
--- /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