[PATCH v2 10/10] mm/madvise: share cold and pageout walk setup

[Gregory Price (Meta)]

madvise_cold() and madvise_pageout() each open-code the same mmu_gather
and page-walk sequence, differing only in the pageout flag they pass to
the walk.

Move that sequence into madvise_lru_vma_range(), which takes the flag.

The walk now gathers into madv_behavior->tlb instead of an mmu_gather
on each caller's stack.

madvise_init_tlb() and madvise_finish_tlb() leave that mmu_gather
untouched for both behaviors, since neither batches TLB flushes
across VMAs.

No functional change intended.

Signed-off-by: Gregory Price (Meta) <gourry@xxxxxxxxxx>
---
 mm/madvise.c | 37 +++++++++----------------------------
 1 file changed, 9 insertions(+), 28 deletions(-)

diff --git a/mm/madvise.c b/mm/madvise.c
index acfe5b945eea..db4f498840eb 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -656,21 +656,23 @@ static const struct mm_walk_ops cold_walk_ops = {
 	.walk_lock = PGWALK_RDLOCK,
 };
 
-static void madvise_cold_page_range(struct mmu_gather *tlb,
-		struct madvise_behavior *madv_behavior)
-
+static void madvise_lru_vma_range(struct madvise_behavior *madv_behavior,
+		bool pageout)
 {
 	struct vm_area_struct *vma = madv_behavior->vma;
 	struct madvise_behavior_range *range = &madv_behavior->range;
+	struct mmu_gather *tlb = madv_behavior->tlb;
 	struct madvise_walk_private walk_private = {
-		.pageout = false,
+		.pageout = pageout,
 		.tlb = tlb,
 	};
 
+	tlb_gather_mmu(tlb, madv_behavior->mm);
 	tlb_start_vma(tlb, vma);
 	walk_page_range_vma(vma, range->start, range->end, &cold_walk_ops,
-			&walk_private);
+			    &walk_private);
 	tlb_end_vma(tlb, vma);
+	tlb_finish_mmu(tlb);
 }
 
 static inline bool can_madv_lru_vma(struct vm_area_struct *vma)
@@ -681,37 +683,18 @@ static inline bool can_madv_lru_vma(struct vm_area_struct *vma)
 static long madvise_cold(struct madvise_behavior *madv_behavior)
 {
 	struct vm_area_struct *vma = madv_behavior->vma;
-	struct mmu_gather tlb;
 
 	if (!can_madv_lru_vma(vma))
 		return -EINVAL;
 
 	lru_add_drain();
-	tlb_gather_mmu(&tlb, madv_behavior->mm);
-	madvise_cold_page_range(&tlb, madv_behavior);
-	tlb_finish_mmu(&tlb);
+	madvise_lru_vma_range(madv_behavior, false);
 
 	return 0;
 }
 
-static void madvise_pageout_page_range(struct mmu_gather *tlb,
-		struct vm_area_struct *vma,
-		struct madvise_behavior_range *range)
-{
-	struct madvise_walk_private walk_private = {
-		.pageout = true,
-		.tlb = tlb,
-	};
-
-	tlb_start_vma(tlb, vma);
-	walk_page_range_vma(vma, range->start, range->end, &cold_walk_ops,
-			    &walk_private);
-	tlb_end_vma(tlb, vma);
-}
-
 static long madvise_pageout(struct madvise_behavior *madv_behavior)
 {
-	struct mmu_gather tlb;
 	struct vm_area_struct *vma = madv_behavior->vma;
 
 	if (!can_madv_lru_vma(vma))
@@ -728,9 +711,7 @@ static long madvise_pageout(struct madvise_behavior *madv_behavior)
 		return 0;
 
 	lru_add_drain();
-	tlb_gather_mmu(&tlb, madv_behavior->mm);
-	madvise_pageout_page_range(&tlb, vma, &madv_behavior->range);
-	tlb_finish_mmu(&tlb);
+	madvise_lru_vma_range(madv_behavior, true);
 
 	return 0;
 }
-- 
2.56.0