[PATCH v2] mmc: Provide tracepoints for request processing

From: Baolin Wang
Date: Fri Mar 25 2016 - 04:20:27 EST


This patch provides some tracepoints for the lifecycle of a request from
fetching to completion to help with performance analysis of MMC subsystem.

Changes since v1:
- Remove the redundant typecasts.
- Fix the bug that could cause a system crash.

Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
---
drivers/mmc/card/block.c | 6 ++
drivers/mmc/card/queue.c | 4 +
drivers/mmc/core/core.c | 5 ++
include/trace/events/mmc.h | 178 ++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 193 insertions(+)
create mode 100644 include/trace/events/mmc.h

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index fe207e5..d372a2d 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -46,6 +46,9 @@

#include "queue.h"

+#define CREATE_TRACE_POINTS
+#include <trace/events/mmc.h>
+
MODULE_ALIAS("mmc:block");
#ifdef MODULE_PARAM_PREFIX
#undef MODULE_PARAM_PREFIX
@@ -1709,6 +1712,7 @@ static u8 mmc_blk_prep_packed_list(struct mmc_queue *mq, struct request *req)
if (phys_segments > max_phys_segs)
break;

+ trace_mmc_block_packed_req(next);
list_add_tail(&next->queuelist, &mqrq->packed->list);
cur = next;
reqs++;
@@ -1870,6 +1874,7 @@ static int mmc_blk_end_packed_req(struct mmc_queue_req *mq_rq)
}
list_del_init(&prq->queuelist);
blk_end_request(prq, 0, blk_rq_bytes(prq));
+ trace_mmc_block_req_done(prq);
i++;
}

@@ -1985,6 +1990,7 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
} else {
ret = blk_end_request(req, 0,
brq->data.bytes_xfered);
+ trace_mmc_block_req_done(req);
}

/*
diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
index 6f4323c..d0388cf 100644
--- a/drivers/mmc/card/queue.c
+++ b/drivers/mmc/card/queue.c
@@ -16,6 +16,7 @@
#include <linux/kthread.h>
#include <linux/scatterlist.h>
#include <linux/dma-mapping.h>
+#include <trace/events/mmc.h>

#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
@@ -64,6 +65,9 @@ static int mmc_queue_thread(void *d)
mq->mqrq_cur->req = req;
spin_unlock_irq(q->queue_lock);

+ if (req)
+ trace_mmc_queue_fetch(req);
+
if (req || mq->mqrq_prev->req) {
set_current_state(TASK_RUNNING);
cmd_flags = req ? req->cmd_flags : 0;
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index f95d41f..cb575ca 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -29,6 +29,7 @@
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/of.h>
+#include <trace/events/mmc.h>

#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
@@ -152,6 +153,8 @@ void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)

led_trigger_event(host->led, LED_OFF);

+ trace_mmc_request_done(host, mrq);
+
if (mrq->sbc) {
pr_debug("%s: req done <CMD%u>: %d: %08x %08x %08x %08x\n",
mmc_hostname(host), mrq->sbc->opcode,
@@ -229,6 +232,8 @@ static int mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
if (mmc_card_removed(host->card))
return -ENOMEDIUM;

+ trace_mmc_request_start(host, mrq);
+
if (mrq->sbc) {
pr_debug("<%s: starting CMD%u arg %08x flags %08x>\n",
mmc_hostname(host), mrq->sbc->opcode,
diff --git a/include/trace/events/mmc.h b/include/trace/events/mmc.h
new file mode 100644
index 0000000..e165ce7
--- /dev/null
+++ b/include/trace/events/mmc.h
@@ -0,0 +1,178 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM mmc
+
+#if !defined(_TRACE_MMC_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_MMC_H
+
+#include <linux/blkdev.h>
+#include <linux/mmc/core.h>
+#include <linux/mmc/host.h>
+#include <linux/tracepoint.h>
+
+DECLARE_EVENT_CLASS(mmc_request,
+
+ TP_PROTO(struct request *rq),
+
+ TP_ARGS(rq),
+
+ TP_STRUCT__entry(
+ __field(sector_t, sector)
+ __field(unsigned int, data_len)
+ __field(int, cmd_dir)
+ __field(struct request *, rq)
+ ),
+
+ TP_fast_assign(
+ __entry->sector = blk_rq_pos(rq);
+ __entry->data_len = blk_rq_bytes(rq);
+ __entry->cmd_dir = rq_data_dir(rq);
+ __entry->rq = rq;
+ ),
+
+ TP_printk("struct request[%p]:sector=%lu rw=%d len=%u",
+ __entry->rq, (unsigned long)__entry->sector,
+ __entry->cmd_dir, __entry->data_len)
+);
+
+DEFINE_EVENT(mmc_request, mmc_queue_fetch,
+
+ TP_PROTO(struct request *rq),
+
+ TP_ARGS(rq)
+
+);
+
+DEFINE_EVENT(mmc_request, mmc_block_packed_req,
+
+ TP_PROTO(struct request *rq),
+
+ TP_ARGS(rq)
+
+);
+
+DEFINE_EVENT(mmc_request, mmc_block_req_done,
+
+ TP_PROTO(struct request *rq),
+
+ TP_ARGS(rq)
+
+);
+
+TRACE_EVENT(mmc_request_start,
+
+ TP_PROTO(struct mmc_host *host, struct mmc_request *mrq),
+
+ TP_ARGS(host, mrq),
+
+ TP_STRUCT__entry(
+ __field(u32, cmd_opcode)
+ __field(u32, cmd_arg)
+ __field(unsigned int, cmd_flags)
+ __field(u32, stop_opcode)
+ __field(u32, stop_arg)
+ __field(unsigned int, stop_flags)
+ __field(u32, sbc_opcode)
+ __field(u32, sbc_arg)
+ __field(unsigned int, sbc_flags)
+ __field(unsigned int, blocks)
+ __field(unsigned int, blksz)
+ __field(unsigned int, data_flags)
+ __field(struct mmc_request *, mrq)
+ __string(name, mmc_hostname(host))
+ ),
+
+ TP_fast_assign(
+ __entry->cmd_opcode = mrq->cmd->opcode;
+ __entry->cmd_arg = mrq->cmd->arg;
+ __entry->cmd_flags = mrq->cmd->flags;
+ __entry->stop_opcode = mrq->stop ? mrq->stop->opcode : 0;
+ __entry->stop_arg = mrq->stop ? mrq->stop->arg : 0;
+ __entry->stop_flags = mrq->stop ? mrq->stop->flags : 0;
+ __entry->sbc_opcode = mrq->sbc ? mrq->sbc->opcode : 0;
+ __entry->sbc_arg = mrq->sbc ? mrq->sbc->arg : 0;
+ __entry->sbc_flags = mrq->sbc ? mrq->sbc->flags : 0;
+ __entry->blksz = mrq->data ? mrq->data->blksz : 0;
+ __entry->blocks = mrq->data ? mrq->data->blocks : 0;
+ __entry->data_flags = mrq->data ? mrq->data->flags : 0;
+ __assign_str(name, mmc_hostname(host));
+ __entry->mrq = mrq;
+ ),
+
+ TP_printk("%s: start struct mmc_request[%p]: "
+ "cmd_opcode=%u cmd_arg=0x%x cmd_flags=0x%x "
+ "stop_opcode=%u stop_arg=0x%x stop_flags=0x%x "
+ "sbc_opcode=%u sbc_arg=0x%x sbc_flags=0x%x "
+ "blocks=%u blksz=%u data_flags=0x%x",
+ __get_str(name), __entry->mrq,
+ __entry->cmd_opcode, __entry->cmd_arg, __entry->cmd_flags,
+ __entry->stop_opcode, __entry->stop_arg, __entry->stop_flags,
+ __entry->sbc_opcode, __entry->sbc_arg, __entry->sbc_flags,
+ __entry->blocks, __entry->blksz, __entry->data_flags)
+);
+
+TRACE_EVENT(mmc_request_done,
+
+ TP_PROTO(struct mmc_host *host, struct mmc_request *mrq),
+
+ TP_ARGS(host, mrq),
+
+ TP_STRUCT__entry(
+ __field(u32, cmd_opcode)
+ __field(int, cmd_err)
+ __array(u32, cmd_resp, 4)
+ __field(u32, stop_opcode)
+ __field(int, stop_err)
+ __array(u32, stop_resp, 4)
+ __field(u32, sbc_opcode)
+ __field(int, sbc_err)
+ __array(u32, sbc_resp, 4)
+ __field(unsigned int, bytes_xfered)
+ __field(int, data_err)
+ __field(struct mmc_request *, mrq)
+ __string(name, mmc_hostname(host))
+ ),
+
+ TP_fast_assign(
+ __entry->cmd_opcode = mrq->cmd->opcode;
+ __entry->cmd_err = mrq->cmd->error;
+ memcpy(__entry->cmd_resp, mrq->cmd->resp, 4);
+ __entry->stop_opcode = mrq->stop ? mrq->stop->opcode : 0;
+ __entry->stop_err = mrq->stop ? mrq->stop->error : 0;
+ __entry->stop_resp[0] = mrq->stop ? mrq->stop->resp[0] : 0;
+ __entry->stop_resp[1] = mrq->stop ? mrq->stop->resp[1] : 0;
+ __entry->stop_resp[2] = mrq->stop ? mrq->stop->resp[2] : 0;
+ __entry->stop_resp[3] = mrq->stop ? mrq->stop->resp[3] : 0;
+ __entry->sbc_opcode = mrq->sbc ? mrq->sbc->opcode : 0;
+ __entry->sbc_err = mrq->sbc ? mrq->sbc->error : 0;
+ __entry->sbc_resp[0] = mrq->sbc ? mrq->sbc->resp[0] : 0;
+ __entry->sbc_resp[1] = mrq->sbc ? mrq->sbc->resp[1] : 0;
+ __entry->sbc_resp[2] = mrq->sbc ? mrq->sbc->resp[2] : 0;
+ __entry->sbc_resp[3] = mrq->sbc ? mrq->sbc->resp[3] : 0;
+ __entry->bytes_xfered = mrq->data ? mrq->data->bytes_xfered : 0;
+ __entry->data_err = mrq->data ? mrq->data->error : 0;
+ __assign_str(name, mmc_hostname(host));
+ __entry->mrq = mrq;
+ ),
+
+ TP_printk("%s: end struct mmc_request[%p]: "
+ "cmd_opcode=%u cmd_err=%d cmd_resp=0x%x 0x%x 0x%x 0x%x "
+ "stop_opcode=%u stop_err=%d stop_resp=0x%x 0x%x 0x%x 0x%x "
+ "sbc_opcode=%u sbc_err=%d sbc_resp=0x%x 0x%x 0x%x 0x%x "
+ "bytes_xfered=%u data_err=%d",
+ __get_str(name), __entry->mrq,
+ __entry->cmd_opcode, __entry->cmd_err,
+ __entry->cmd_resp[0], __entry->cmd_resp[1],
+ __entry->cmd_resp[2], __entry->cmd_resp[3],
+ __entry->stop_opcode, __entry->stop_err,
+ __entry->stop_resp[0], __entry->stop_resp[1],
+ __entry->stop_resp[2], __entry->stop_resp[3],
+ __entry->sbc_opcode, __entry->sbc_err,
+ __entry->sbc_resp[0], __entry->sbc_resp[1],
+ __entry->sbc_resp[2], __entry->sbc_resp[3],
+ __entry->bytes_xfered, __entry->data_err)
+);
+
+#endif /* _TRACE_MMC_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
--
1.7.9.5