Re: [PATCH] likely cleanup: remove unlikely for kfree(NULL)
From: Kyle Moffett
Date: Wed Apr 26 2006 - 15:08:38 EST
Here's code that I've found works as well as can be expected under
both GCC 3 and GCC 4. If xp is a known-NULL constant the whole
function will be optimized out completely. If xp is known-not-NULL,
then it will optimize to a kfree function without the null check.
Otherwise it optimizes to call the out-of-line version.
Cheers,
Kyle Moffett
static inline void kfree(void *ptr)
{
if (__builtin_constant_p((ptr == NULL))) {
if (ptr)
kfree_nonnull(ptr);
} else {
kfree_unknown(ptr);
}
}
void kfree_nonnull(void *ptr)
{
/* kfree code here, no null check */
}
void kfree_unknown(void *ptr)
{
if (ptr)
kfree_nonnull(ptr);
}
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