Messages in this thread | | | Date | Wed, 14 Dec 2011 14:28:44 +1100 | From | Dave Chinner <> | Subject | Re: [RFC][PATCH] writeback: Unduplicate writeback reason |
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On Tue, Dec 13, 2011 at 08:14:00PM -0500, Steven Rostedt wrote: > Names of the writeback reasons are used in both the main kernel as well > as for parsing the tracepoint format file. Instead of duplicating the > names in two locations making it likely that they may become out of > sync, use some macro magic to make sure all the names stay in sync. Any > update only needs to happen in one spot for it to take place in all > locations. > > Note, this is an RFC patch, and it probably needs much better comments > (well, it currently has no comments), and the C() macro probably should > have a different name too.
I'm not sure this is a pattern we want to repeat all over the place - print_symbolic() is quite widely used and adding macro redefinitions all over the place doesn't fill me with joy.
AFAICT this code doesn't need a declared array to work so you can just use a preprocessor construct like this (as used in XFS):
#define value_1 1 #define value_2 2 .....
or
enum { value_1 = 1, value_2 = 2, ..... }
followed by:
#define VALUES \ { value_1, "Value 1" }, \ { value_2, "Value 2" }, \ .....
And it just uses print_symbolic(__entry->value, VALUES); to print them out.
If this construct does everything requiredi, then I think it is a much better pattern to use because it's easy to maintain, doesn't require an array to be declared in a C file and doesn't require macro tricks to do it's job....
Cheers,
Dave. -- Dave Chinner david@fromorbit.com
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