From ecf46abdd32a35fcd7dfeef72600a065425532b3 Mon Sep 17 00:00:00 2001
From: Gerald Schaefer <geraldsc@linux.vnet.ibm.com>
Date: Fri, 29 May 2015 15:34:51 +0200
Subject: [PATCH] s390/mm: enable gup code for NUMA
Force get_user_page() to take the slow path for NUMA migration pages.
Signed-off-by: Gerald Schaefer <geraldsc@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
arch/s390/mm/gup.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/arch/s390/mm/gup.c b/arch/s390/mm/gup.c
index 1eb41bb3010cf..12bbf0e8478f8 100644
--- a/arch/s390/mm/gup.c
+++ b/arch/s390/mm/gup.c
@@ -30,6 +30,9 @@ static inline int gup_pte_range(pmd_t *pmdp, pmd_t pmd, unsigned long addr,
do {
pte = *ptep;
barrier();
+ /* Similar to the PMD case, NUMA hinting must take slow path */
+ if (pte_protnone(pte))
+ return 0;
if ((pte_val(pte) & mask) != 0)
return 0;
VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
@@ -125,6 +128,13 @@ static inline int gup_pmd_range(pud_t *pudp, pud_t pud, unsigned long addr,
if (pmd_none(pmd) || pmd_trans_splitting(pmd))
return 0;
if (unlikely(pmd_large(pmd))) {
+ /*
+ * NUMA hinting faults need to be handled in the GUP
+ * slowpath for accounting purposes and so that they
+ * can be serialised against THP migration.
+ */
+ if (pmd_protnone(pmd))
+ return 0;
if (!gup_huge_pmd(pmdp, pmd, addr, next,
write, pages, nr))
return 0;
--
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