Initial blktrace support
This doesn't work yet, just committing what little bits I did as not
to lose them.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/blktrace_api.h b/blktrace_api.h
new file mode 100644
index 0000000..61b405a
--- /dev/null
+++ b/blktrace_api.h
@@ -0,0 +1,128 @@
+#ifndef BLKTRACEAPI_H
+#define BLKTRACEAPI_H
+
+#include <asm/types.h>
+
+/*
+ * Trace categories
+ */
+enum {
+ BLK_TC_READ = 1 << 0, /* reads */
+ BLK_TC_WRITE = 1 << 1, /* writes */
+ BLK_TC_BARRIER = 1 << 2, /* barrier */
+ BLK_TC_SYNC = 1 << 3, /* sync */
+ 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_AHEAD = 1 << 11, /* readahead */
+ BLK_TC_META = 1 << 12, /* metadata */
+
+ 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 {
+ __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 */
+};
+
+/*
+ * Notify events.
+ */
+enum blktrace_notify {
+ __BLK_TN_PROCESS = 0, /* establish pid/name mapping */
+ __BLK_TN_TIMESTAMP, /* include system clock */
+};
+
+/*
+ * 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_TN_PROCESS (__BLK_TN_PROCESS | BLK_TC_ACT(BLK_TC_NOTIFY))
+#define BLK_TN_TIMESTAMP (__BLK_TN_TIMESTAMP | BLK_TC_ACT(BLK_TC_NOTIFY))
+
+#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 nanoseconds */
+ __u64 sector; /* disk offset */
+ __u32 bytes; /* transfer length */
+ __u32 action; /* what happened */
+ __u32 pid; /* who did it */
+ __u32 device; /* device identifier (dev_t) */
+ __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 device_from;
+ __u64 sector;
+};
+
+/*
+ * User setup structure passed with BLKSTARTTRACE
+ */
+struct blk_user_trace_setup {
+ char name[32]; /* output */
+ __u16 act_mask; /* input */
+ __u32 buf_size; /* input */
+ __u32 buf_nr; /* input */
+ __u64 start_lba;
+ __u64 end_lba;
+ __u32 pid;
+};
+
+#define BLKTRACESETUP _IOWR(0x12,115,struct blk_user_trace_setup)
+#define BLKTRACESTART _IO(0x12,116)
+#define BLKTRACESTOP _IO(0x12,117)
+#define BLKTRACETEARDOWN _IO(0x12,118)
+
+#endif