From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
There is missing optimization in zero_p4d_populate() that can save
some memory when mapping zero shadow. Implement it like as others.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
---
mm/kasan/kasan_init.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/mm/kasan/kasan_init.c b/mm/kasan/kasan_init.c
index b96a5f7..554e4c0 100644
--- a/mm/kasan/kasan_init.c
+++ b/mm/kasan/kasan_init.c
@@ -118,6 +118,18 @@ static void __init zero_p4d_populate(pgd_t *pgd, unsigned long addr,
do {
next = p4d_addr_end(addr, end);
+ if (IS_ALIGNED(addr, P4D_SIZE) && end - addr >= P4D_SIZE) {
+ pud_t *pud;
+ pmd_t *pmd;
+
+ p4d_populate(&init_mm, p4d, lm_alias(kasan_zero_pud));
+ pud = pud_offset(p4d, addr);
+ pud_populate(&init_mm, pud, lm_alias(kasan_zero_pmd));
+ pmd = pmd_offset(pud, addr);
+ pmd_populate_kernel(&init_mm, pmd,
+ lm_alias(kasan_zero_pte));
+ continue;
+ }
if (p4d_none(*p4d)) {
p4d_populate(&init_mm, p4d,
--
2.7.4
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