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block: use standard blktrace API to output cgroup info for debug notes

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Currently cfq/bfq/blk-throttle output cgroup info in trace in their own
way. Now we have standard blktrace API for this, so convert them to use
it.

Note, this changes the behavior a little bit. cgroup info isn't output
by default, we only do this with 'blk_cgroup' option enabled. cgroup
info isn't output as a string by default too, we only do this with
'blk_cgname' option enabled. Also cgroup info is output in different
position of the note string. I think these behavior changes aren't a big
issue (actually we make trace data shorter which is good), since the
blktrace note is solely for debugging.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Shaohua Li
2017-07-12 11:49:56 -07:00
committed by Jens Axboe
parent 69fd5c3917
commit 35fe6d7632
5 changed files with 35 additions and 24 deletions
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12
kernel/trace/blktrace.c
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@@ -154,7 +154,8 @@ static void trace_note_time(struct blk_trace *bt)
local_irq_restore(flags);
}
void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
void __trace_note_message(struct blk_trace *bt, struct blkcg *blkcg,
const char *fmt, ...)
{
int n;
va_list args;
@@ -178,7 +179,14 @@ void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
va_end(args);
if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
blkcg = NULL;
#ifdef CONFIG_BLK_CGROUP
trace_note(bt, 0, BLK_TN_MESSAGE, buf, n,
blkcg ? cgroup_get_kernfs_id(blkcg->css.cgroup) : NULL);
#else
trace_note(bt, 0, BLK_TN_MESSAGE, buf, n, NULL);
#endif
local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(__trace_note_message);
@@ -375,7 +383,7 @@ static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
return PTR_ERR(msg);
bt = filp->private_data;
__trace_note_message(bt, "%s", msg);
__trace_note_message(bt, NULL, "%s", msg);
kfree(msg);
return count;