The period check of _PAGE_NUMA can probably trigger the check on
the correctly placed page. For this case, we can just insert hpte and
do fast exception return.
Signed-off-by: Liu Ping Fan <pingf...@linux.vnet.ibm.com>
---
arch/powerpc/mm/hash_utils_64.c | 34 +++++++++++++++++++++++++++++++++-
1 file changed, 33 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 9bf1195..735678c 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -965,6 +965,10 @@ int hash_page(unsigned long ea, unsigned long access,
unsigned long trap)
const struct cpumask *tmp;
int rc, user_region = 0, local = 0;
int psize, ssize;
+ pte_t old, new;
+ struct vm_area_struct *vma;
+ int page_nid, target_nid;
+ struct page *test_page;
DBG_LOW("hash_page(ea=%016lx, access=%lx, trap=%lx\n",
ea, access, trap);
@@ -1033,12 +1037,40 @@ int hash_page(unsigned long ea, unsigned long access,
unsigned long trap)
/* Get PTE and page size from page tables */
ptep = find_linux_pte_or_hugepte(pgdir, ea, &hugeshift);
- if (ptep == NULL || !pte_present(*ptep) || pte_numa(*ptep)) {
+ if (ptep == NULL || !pte_present(*ptep)) {
DBG_LOW(" no PTE !\n");
rc = 1;
goto bail;
}
+ old = pte_val(*ptep);
+ if (pte_numa(old)) {
+ /* If fail to lock, let do_page_fault() to handle it */
+ if (down_read_trylock(&mm->mmap_sem)) {
+ vma = find_vma(mm, ea);
+ up_read(&mm->mmap_sem);
+ test_page = pte_page(old);
+ page_nid = page_to_nid(test_page);
+ target_nid = numa_migrate_prep(test_page, vma, ea,
+ page_nid);
+ if (target_nid < 0) {
+ new = pte_mknonnuma(old);
+ /* If ptep is modified under us,
+ * just retry the access
+ */
+ if (unlikely(cmpxchg(ptep, old, new) != old)) {
+ put_page(test_page);
+ return 0;
+ }
+ put_page(test_page);
+ }
+ } else {
+ put_page(test_page);
+ rc = 1;
+ goto bail;
+ }
+ }
+
/* Add _PAGE_PRESENT to the required access perm */
access |= _PAGE_PRESENT;
--
1.8.1.4
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