Messages in this thread | | | Date | Wed, 21 Mar 2007 21:59:33 -0700 | From | "Wink Saville" <> | Subject | Re: [PATCH 2/7] Initial implementation of the trec driver and include files |
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On 3/21/07, Johannes Weiner <hannes-kernel@saeurebad.de> wrote: > Hi, > > On Wed, Mar 21, 2007 at 09:49:12AM -0700, Wink Saville wrote: > > >>Please don't use camel-case - in general. > > >> > > Would p_next, p_cur and p_end be OK? > > I think it's generally disliked. Quoting Documentation/CodingStyle: > > ``Encoding the type of a function into the name (so-called Hungarian > notation) is brain damaged - the compiler knows the types anyway and can > check those, and it only confuses the programmer. No wonder MicroSoft > makes buggy programs.'' >
I'll change it to; next, cur, end (when in rome do as the romans)
> > You can implement a sysctl-setting to enable/disable the whole system > (which then would be runtime changeable).
Generally the way I've used this in the kernel is sprinkle them liberally where I'm trying to track down a bug or understand how some code works and then disable some of them using ZREC's but then reenable as necessary. Finally, I remove them all usually by reverting to the original code.
In userland I have a more sophisticated version which combines TREC's and printf's in one macro with a "debug variable" defined as a set of bits controlling the enable/disable sets of these. For example:
DPRP1(1 << 2, "This is a DPR with parameter=%d", xyz);
#define DPRP1(__bits, __format, __param, ...) \ do { \ if (((__bits) << 16) & dbg_variable) \ printf((__format), __param...); \ if ((__bits) & dbg_variable) \ TREC1((__param)); \ } while (0)
The above divides "dbg_variable" into 2 16 bit fields, the upper 16 bits control if the printf is enabled and the lower 16 bits controls if the TREC1 is enabled. What I envision happening would possibly to expose the "dbg_variable" via procfs where it could "easily" be modified from userland.
Anyway, for my immediate needs I just needed the TREC's so I could understand the inner workings of the kernel better and assist in debugging. I've submitted it as a patch incase anyone might be interested.
Actually, are you interested in using them?
In anycase thanks for the feed back.
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