Re: [PATCH] no need to check for NULL before calling kfree() -fs/ext2/

[Denis Vlasenko]

> > It's impossible to be otherwise. A call requires
> > that the return address be written to memory (the stack),
> > using register indirection (the stack-pointer).
> 
> and it's a so common pattern that it's optimized to death. Internally a
> call gets transformed to 2 uops or so, one is push eip, the other is the
> jmp (which gets then just absorbed by the "what is the next eip" logic,
> just as a "jmp"s are 0 cycles)

Arjan, you overlook the fact that kfree() contains 'if(!p) return;' too.
call + test-and-branch can never be faster than test+and+branch.
Maybe on the really clever CPU it can take the same time, but not faster...
--
vda

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