Re: [PATCH 3/4] KVM-S390: Less function calls in kvm_s390_import_bp_data() after error detection

From: Paolo Bonzini
Date: Wed Aug 31 2016 - 08:29:52 EST




On 22/08/2016 23:17, SF Markus Elfring wrote:
>> If in doubt, the compiler will be _much_ better at optimizing
>> that kind of stuff anyway.
>
> Which compiler (or optimizer) implementation is capable to restructure
> the jump targets for you automatically in the way I propose here?

If kfree were implemented as

if (p)
really_kfree(p);

then the compiler would be able to jump over the NULL test. In
principle one could also add a "does nothing if NULL" attribute to GCC
and annotate kfree with it.

Paolo