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Subject[PATCH mm-unstable 3/4] mm: multi-gen LRU: add helpers in page table walks
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Add helpers to page table walking code:
- Clarifies intent via name "should_walk_mmu" and "should_clear_pmd_young"
- Avoids repeating same logic in two places

Signed-off-by: T.J. Alumbaugh <talumbau@google.com>
---
mm/vmscan.c | 20 +++++++++++++++-----
1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index e088db138f5f..ad0f589d32e6 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3234,6 +3234,16 @@ DEFINE_STATIC_KEY_ARRAY_FALSE(lru_gen_caps, NR_LRU_GEN_CAPS);
#define get_cap(cap) static_branch_unlikely(&lru_gen_caps[cap])
#endif

+static bool should_walk_mmu(void)
+{
+ return arch_has_hw_pte_young() && get_cap(LRU_GEN_MM_WALK);
+}
+
+static bool should_clear_pmd_young(void)
+{
+ return arch_has_hw_nonleaf_pmd_young() && get_cap(LRU_GEN_NONLEAF_YOUNG);
+}
+
/******************************************************************************
* shorthand helpers
******************************************************************************/
@@ -4098,7 +4108,7 @@ static void walk_pmd_range_locked(pud_t *pud, unsigned long addr, struct vm_area
goto next;

if (!pmd_trans_huge(pmd[i])) {
- if (arch_has_hw_nonleaf_pmd_young() && get_cap(LRU_GEN_NONLEAF_YOUNG))
+ if (should_clear_pmd_young())
pmdp_test_and_clear_young(vma, addr, pmd + i);
goto next;
}
@@ -4191,7 +4201,7 @@ static void walk_pmd_range(pud_t *pud, unsigned long start, unsigned long end,
#endif
walk->mm_stats[MM_NONLEAF_TOTAL]++;

- if (arch_has_hw_nonleaf_pmd_young() && get_cap(LRU_GEN_NONLEAF_YOUNG)) {
+ if (should_clear_pmd_young()) {
if (!pmd_young(val))
continue;

@@ -4493,7 +4503,7 @@ static bool try_to_inc_max_seq(struct lruvec *lruvec, unsigned long max_seq,
* handful of PTEs. Spreading the work out over a period of time usually
* is less efficient, but it avoids bursty page faults.
*/
- if (!arch_has_hw_pte_young() || !get_cap(LRU_GEN_MM_WALK)) {
+ if (!should_walk_mmu()) {
success = iterate_mm_list_nowalk(lruvec, max_seq);
goto done;
}
@@ -5730,10 +5740,10 @@ static ssize_t enabled_show(struct kobject *kobj, struct kobj_attribute *attr, c
if (get_cap(LRU_GEN_CORE))
caps |= BIT(LRU_GEN_CORE);

- if (arch_has_hw_pte_young() && get_cap(LRU_GEN_MM_WALK))
+ if (should_walk_mmu())
caps |= BIT(LRU_GEN_MM_WALK);

- if (arch_has_hw_nonleaf_pmd_young() && get_cap(LRU_GEN_NONLEAF_YOUNG))
+ if (should_clear_pmd_young())
caps |= BIT(LRU_GEN_NONLEAF_YOUNG);

return sysfs_emit(buf, "0x%04x\n", caps);
--
2.40.1.698.g37aff9b760-goog
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