Hi Zhong, On Thu, Jul 24, 2014 at 05:36:25PM +0800, Li Zhong wrote: > It is possible for some platforms, such as powerpc to set HPAGE_SHIFT to > 0 to indicate huge pages not supported. > > When this is the case, hugetlbfs could be disabled during boot time: > hugetlbfs: disabling because there are no supported hugepage sizes > > Then in dissolve_free_huge_pages(), order is kept maximum (64 for > 64bits), and the for loop below won't end: > for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << order) At first I wonder that why could dissolve_free_huge_pages() is called if the platform doesn't support hugetlbfs. But I found that the function is called by memory hotplug code without checking hugepage support. So it looks to me straightforward and self-descriptive to check hugepage_supported() just before calling dissolve_free_huge_pages(). Thanks, Naoya Horiguchi > The fix below returns directly if the order isn't set to a correct > value. > > Signed-off-by: Li Zhong <zhong@xxxxxxxxxxxxxxxxxx> > --- > mm/hugetlb.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 2024bbd..a950817 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -1093,6 +1093,10 @@ void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn) > for_each_hstate(h) > if (order > huge_page_order(h)) > order = huge_page_order(h); > + > + if (order == 8 * sizeof(void *)) > + return; > + > VM_BUG_ON(!IS_ALIGNED(start_pfn, 1 << order)); > for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << order) > dissolve_free_huge_page(pfn_to_page(pfn)); > > > -- > 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/ . > Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a> > -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>