On Fri, Nov 18, 2011 at 3:04 PM, Hillf Danton <dhillf@xxxxxxxxx> 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. > > If racing, our job is done. > > Signed-off-by: Hillf Danton <dhillf@xxxxxxxxx> > --- > > --- a/mm/hugetlb.c Fri Nov 18 21:38:30 2011 > +++ b/mm/hugetlb.c Fri Nov 18 21:48:15 2011 > @@ -2407,7 +2407,14 @@ retry_avoidcopy: > BUG_ON(page_count(old_page) != 1); > BUG_ON(huge_pte_none(pte)); > spin_lock(&mm->page_table_lock); > - goto retry_avoidcopy; > + ptep = huge_pte_offset(mm, address & huge_page_mask(h)); > + if (likely(pte_same(huge_ptep_get(ptep), pte))) > + goto retry_avoidcopy; > + /* > + * race occurs while re-acquiring page_table_lock, and > + * our job is done. > + */ > + return 0; > } > WARN_ON_ONCE(1); > } I'm not sure about the veracity of the race condition, but you better do spin_unlock before you return. -- 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