Am Donnerstag 04 November 2010 schrieb Christian Lamparter: > On Thu, Nov 4, 2010 at 7:38 PM, Ivo van Doorn <ivdoorn@xxxxxxxxx> wrote: > > From: Helmut Schaa <helmut.schaa@xxxxxxxxxxxxxx> > > > > The skb allocation should really only fail under high memory pressure > > or other uncommon situations. Hence, mark the allocation failure check > > as unlikely. > > > > Signed-off-by: Helmut Schaa <helmut.schaa@xxxxxxxxxxxxxx> > > Signed-off-by: Ivo van Doorn <IvDoorn@xxxxxxxxx> > > --- > > drivers/net/wireless/rt2x00/rt2x00dev.c | 2 +- > > 1 files changed, 1 insertions(+), 1 deletions(-) > > > > diff --git a/drivers/net/wireless/rt2x00/rt2x00dev.c b/drivers/net/wireless/rt2x00/rt2x00dev.c > > index 5ba79b9..a5c7a4f 100644 > > --- a/drivers/net/wireless/rt2x00/rt2x00dev.c > > +++ b/drivers/net/wireless/rt2x00/rt2x00dev.c > > @@ -491,7 +491,7 @@ void rt2x00lib_rxdone(struct queue_entry *entry) > > * received frame and reuse the existing buffer. > > */ > > skb = rt2x00queue_alloc_rxskb(entry); > > - if (!skb) > > + if (unlikely(!skb)) > > goto submit_entry; > > > > /* > > -- > err, wait a sec, I've been looking for this mail for some time, but: > > http://mail.linux.ie/pipermail/ilug/2004-December/075654.html > > "Note tests for NULL (!something) don't need an unlikely as gcc does > that by default itself." > > But there's more, according to http://gcc.gnu.org/news/profiledriven.html: > (static program profile) gcc expect pointers to be non-null > > (therefore all !skb tests should be unlikely branches by default, or?) Interesting, didn't know that. I've just given it a try and the MIPS assembly indeed stays the same with and without the unlikely. Nevertheless, I've found quite a number of unlikely(!x) checks throughout the net stack ... But still, this seems unnecessary. John, please drop this patch. Thanks Christian, Helmut -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
