3.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Li Zhong <[email protected]>

commit d0177639310d23c7739500df3c6ce6fdfe34acec upstream.

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)

As suggested by Naoya, below fix checks hugepages_supported() before
calling dissolve_free_huge_pages().

[[email protected]: no legitimate reason to call dissolve_free_huge_pages() 
when !hugepages_supported()]
Signed-off-by: Li Zhong <[email protected]>
Acked-by: Naoya Horiguchi <[email protected]>
Acked-by: David Rientjes <[email protected]>
Signed-off-by: David Rientjes <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 mm/hugetlb.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1089,6 +1089,9 @@ void dissolve_free_huge_pages(unsigned l
        unsigned long pfn;
        struct hstate *h;
 
+       if (!hugepages_supported())
+               return;
+
        /* Set scan step to minimum hugepage size */
        for_each_hstate(h)
                if (order > huge_page_order(h))


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to