Re: [PATCH 00/11] [GIT PULL] more updates for the tag format

From: Theodore Tso
Date: Wed Jun 10 2009 - 09:02:23 EST


On Wed, Jun 10, 2009 at 01:11:40PM +0200, Frédéric Weisbecker wrote:
> Well, indeed I had worries, but I discussed about it with Steven and
> now I actually
> think this new tag format is much more powerful than printf style.
> It brings a cleaner, and much higher level way to control the data exports.
>
> But it would be nice to read some opinions from end users (end
> developers) of TRACE_EVENT().

Maybe I'm missing something, but looks like the this new format, while
simpler and easier to read, doesn't have support for using a more
complicated C expression as a printk argument. For example:

TP_printk("dev %s ino %lu mode %d uid %u gid %u blocks %llu",
jbd2_dev_to_name(__entry->dev), __entry->ino, __entry->mode,
__entry->uid, __entry->gid, __entry->blocks)

How should I handle the "jbd2_dev_to_name(__entry->dev)" argument to
TP_printk? The whole point of calling jbd2_dev_to_name() at TP_printk
time is to not bloat the ring buffer with a 32 byte devname.

- Ted
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