Messages in this thread |  | | | Subject | Re: kfree(NULL) | | From | Steven Rostedt <> | | Date | Fri, 21 Apr 2006 16:54:13 -0400 |
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On Fri, 2006-04-21 at 13:30 -0700, Vernon Mauery wrote: > On Friday 21 April 2006 12:22, you wrote:
> > What makes you confident that the static inline version gives a time > > saving? > > A static inline wrapper would mean that it wouldn't have to make a function > call just to check if the pointer is NULL. A simple NULL check is faster > than a function call and then a simple NULL check. In other words, there > would be no pushing and popping the stack. In almost all cases, replacing an > inline function with a non-inline function means a trade-off between speed > and size.
Andrew Morton just submitted a patch to -mm that fixes the two problem places that called kfree(NULL) more than it calls kfree(non-NULL).
Besides the places that are now fixed, the inline doesn't save much. Since most cases kfree(non-NULL) is called, so the NULL is really an unlikely case. Thus you just increased the size of the kernel, for virtually no speed savings.
-- Steve
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