[RFC PATCH 4/5] mm/damon/vaddr: extend apply_probes() for hugetlb

[SJ Park <sj@kernel.org>]

DAMON virtual address space operation set(vaddr) does not support
hugetlb pages in apply_probes.  Extend it for hugetlb pages.

Signed-off-by: SJ Park <sj@kernel.org>
---
 mm/damon/vaddr.c | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
index 7c548ec0cf6b5..45239f05e113b 100644
--- a/mm/damon/vaddr.c
+++ b/mm/damon/vaddr.c
@@ -598,6 +598,34 @@ static int damon_va_probe_pmd_entry(pmd_t *pmd, unsigned long addr,
 	return 0;
 }
 
+#ifdef CONFIG_HUGETLB_PAGE
+static int damon_va_probe_hugetlb_entry(pte_t *pte, unsigned long hmask,
+		unsigned long addr, unsigned long end, struct mm_walk *walk)
+{
+	struct damon_va_probe_walk_private *priv = walk->private;
+	struct hstate *h = hstate_vma(walk->vma);
+	struct folio *folio;
+	spinlock_t *ptl;
+	pte_t entry;
+
+	ptl = huge_pte_lock(h, walk->mm, pte);
+	entry = huge_ptep_get(walk->mm, addr, pte);
+	if (!pte_present(entry))
+		goto out;
+
+	folio = pfn_folio(pte_pfn(entry));
+	folio_get(folio);
+	damon_va_probe_folio(priv->ctx, priv->r, folio);
+	folio_put(folio);
+
+out:
+	spin_unlock(ptl);
+	return 0;
+}
+#else
+#define damon_va_probe_hugetlb_entry NULL
+#endif /* CONFIG_HUGETLB_PAGE */
+
 static void __damon_va_apply_probes(struct damon_ctx *ctx,
 		struct mm_struct *mm,  struct damon_region *r)
 {
@@ -607,7 +635,7 @@ static void __damon_va_apply_probes(struct damon_ctx *ctx,
 	};
 	struct mm_walk_ops damon_probe_walk_ops = {
 		.pmd_entry = damon_va_probe_pmd_entry,
-		.hugetlb_entry = NULL,
+		.hugetlb_entry = damon_va_probe_hugetlb_entry,
 	};
 	unsigned long addr = r->sampling_addr;
 
-- 
2.47.3