On Sat, Nov 19, 2011 at 3:39 AM, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > On Fri, 18 Nov 2011 17:11:28 +0100 > Michal Hocko <mhocko@xxxxxxx> wrote: > >> On Fri 18-11-11 23:23:12, Hillf Danton wrote: >> > On Fri, Nov 18, 2011 at 11:07 PM, Michal Hocko <mhocko@xxxxxxx> wrote: >> > > On Fri 18-11-11 22:04:37, Hillf Danton wrote: >> > >> In the error path that we fail to allocate new huge page, before try again, we >> > >> have to check race since page_table_lock is re-acquired. >> > > >> > > I do not think we can race here because we are serialized by >> > > hugetlb_instantiation_mutex AFAIU. Without this lock, however, we could >> > > fall into avoidcopy and shortcut despite the fact that other thread has >> > > already did the job. >> > > >> > > The mutex usage is not obvious in hugetlb_cow so maybe we want to be >> > > explicit about it (either a comment or do the recheck). >> > > >> > >> > Then the following check is unnecessary, no? >> >> Hmm, thinking about it some more, I guess we have to recheck because we >> can still race with page migration. So we need you patch. >> >> Reviewed-by: Michal Hocko <mhocko@xxxxxxx> > > So we need a new changelog. How does this look? > Thanks Andrew and Michal:) Best regards Hillf -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href