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| author | Li Zefan <lizf@cn.fujitsu.com> | 2009-04-14 14:00:05 +0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-04-16 10:10:59 +0200 |
| commit | 1d54ad6da9192fed5dd3b60224d9f2dfea0dcd82 (patch) | |
| tree | fd5917f144ec820b933795bedd7eddea96bee374 /include/linux/blktrace_api.h | |
| parent | 9908c30997b8a73c95f836170b9998dae9aa3f4a (diff) | |
| download | lwn-1d54ad6da9192fed5dd3b60224d9f2dfea0dcd82.tar.gz lwn-1d54ad6da9192fed5dd3b60224d9f2dfea0dcd82.zip | |
blktrace: add trace/ to /sys/block/sda
Impact: allow ftrace-plugin blktrace to trace device-mapper devices
To trace a single partition:
# echo 1 > /sys/block/sda/sda1/enable
To trace the whole sda instead:
# echo 1 > /sys/block/sda/enable
Thus we also fix an issue reported by Ted, that ftrace-plugin blktrace
can't be used to trace device-mapper devices.
Now:
# echo 1 > /sys/block/dm-0/trace/enable
echo: write error: No such device or address
# mount -t ext4 /dev/dm-0 /mnt
# echo 1 > /sys/block/dm-0/trace/enable
# echo blk > /debug/tracing/current_tracer
Reported-by: Theodore Tso <tytso@mit.edu>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Shawn Du <duyuyang@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
LKML-Reference: <49E42665.6020506@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/linux/blktrace_api.h')
| -rw-r--r-- | include/linux/blktrace_api.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h index 267edc4017ee..62763c952854 100644 --- a/include/linux/blktrace_api.h +++ b/include/linux/blktrace_api.h @@ -198,6 +198,7 @@ extern int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, char __user *arg); extern int blk_trace_startstop(struct request_queue *q, int start); extern int blk_trace_remove(struct request_queue *q); +extern int blk_trace_init_sysfs(struct device *dev); extern struct attribute_group blk_trace_attr_group; @@ -210,6 +211,11 @@ extern struct attribute_group blk_trace_attr_group; # define blk_trace_startstop(q, start) (-ENOTTY) # define blk_trace_remove(q) (-ENOTTY) # define blk_add_trace_msg(q, fmt, ...) do { } while (0) +static inline int blk_trace_init_sysfs(struct device *dev) +{ + return 0; +} + #endif /* CONFIG_BLK_DEV_IO_TRACE */ #endif /* __KERNEL__ */ |