From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Date: Wed, 31 Aug 2016 12:29:41 +0000 Subject: Re: [PATCH 3/4] KVM-S390: Less function calls in kvm_s390_import_bp_data() after error detection Message-Id: <57711295-6c3c-c2f3-41e3-a85a552de82b@redhat.com> List-Id: References: <82b84c9c-38a4-4d17-910f-312668dbae01@users.sourceforge.net> <47f88a11-b949-28ed-5589-925888a37574@users.sourceforge.net> <20160822150048.309a3e10.cornelia.huck@de.ibm.com> <20160822213736.62f1ae29.cornelia.huck@de.ibm.com> <5da7978a-922b-8ccc-fce4-2bffffca888f@users.sourceforge.net> In-Reply-To: <5da7978a-922b-8ccc-fce4-2bffffca888f@users.sourceforge.net> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: SF Markus Elfring , Cornelia Huck Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org, =?UTF-8?Q?Christian_Borntr=c3=a4ger?= , David Hildenbrand , Heiko Carstens , Martin Schwidefsky , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , LKML , kernel-janitors@vger.kernel.org, Julia Lawall 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