On Thu 23-08-18 22:57:42, Wei Yang wrote: > On Thu, Aug 23, 2018 at 03:13:39PM +0200, Michal Hocko wrote: > >On Thu 23-08-18 21:07:30, Wei Yang wrote: > >> Each time SECTIONS_PER_ROOT number of mem_section is allocated when > >> mem_section[root] is null. This means only (1 / SECTIONS_PER_ROOT) chance > >> of the mem_section[root] check is false. > >> > >> This patch adds likely to the if check to optimize this a little. > > > >Could you evaluate how much does this help if any? Does this have any > >impact on the initialization path at all? > > Let me test on my 4G machine with this patch :-) Well, this should have been done before posting the patch. In general, though, you should have some convincing numbers in order to add new likely/unlikely annotations. They are rarely helpful and they tend to rot over time. Steven Rostedt has made some test few years back and found out that a vast majority of those annotation were simply wrong. -- Michal Hocko SUSE Labs
