Re: [PATCH] Allow NULL pointers in percpu_free

From: Daniel Walker
Date: Fri Nov 17 2006 - 13:14:44 EST


On Fri, 2006-11-17 at 13:07 -0500, Alan Stern wrote:
> On Fri, 17 Nov 2006, Daniel Walker wrote:
>
> > On Fri, 2006-11-17 at 12:36 -0500, Alan Stern wrote:
> >
> > > void percpu_free(void *__pdata)
> > > {
> > > + if (!__pdata)
> > > + return;
> >
> > Should be unlikely() right?
>
> It certainly could be. I tend not to put such annotations in my code, but
> it wouldn't hurt.

It's actually a really good idea to add them .. I've noticed they tend
to make my kernels smaller, although I wouldn't expect that to always be
the case.. Another reason is that in -mm we can track how often this
condition is triggered with likely profiling. With kfree, for instance,
there were a number of callers that frequently called kfree(NULL), which
IMO isn't good.

Daniel

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