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From:   Liam Howlett <liam.howlett@oracle.com>
To:     "maple-tree@lists.infradead.org" <maple-tree@lists.infradead.org>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
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        Rik van Riel <riel@surriel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Michel Lespinasse <walken.cr@gmail.com>,
        Liam Howlett <liam.howlett@oracle.com>
Subject: [PATCH 77/94] mm/ksm: Use maple tree iterators instead of vma linked
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Thread-Topic: [PATCH 77/94] mm/ksm: Use maple tree iterators instead of vma
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Date:   Wed, 28 Apr 2021 15:36:25 +0000
Message-ID: <20210428153542.2814175-78-Liam.Howlett@Oracle.com>
References: <20210428153542.2814175-1-Liam.Howlett@Oracle.com>
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Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
---
 mm/ksm.c | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/mm/ksm.c b/mm/ksm.c
index ced6830d0ff4..aa0cfe1ef2d7 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -969,11 +969,14 @@ static int unmerge_and_remove_all_rmap_items(void)
 						struct mm_slot, mm_list);
 	spin_unlock(&ksm_mmlist_lock);
=20
-	for (mm_slot =3D ksm_scan.mm_slot;
-			mm_slot !=3D &ksm_mm_head; mm_slot =3D ksm_scan.mm_slot) {
+	for (mm_slot =3D ksm_scan.mm_slot; mm_slot !=3D &ksm_mm_head;
+	     mm_slot =3D ksm_scan.mm_slot) {
+		MA_STATE(mas, &mm_slot->mm->mm_mt, 0, 0);
+
 		mm =3D mm_slot->mm;
 		mmap_read_lock(mm);
-		for (vma =3D mm->mmap; vma; vma =3D vma->vm_next) {
+		rcu_read_lock();
+		mas_for_each(&mas, vma, ULONG_MAX) {
 			if (ksm_test_exit(mm))
 				break;
 			if (!(vma->vm_flags & VM_MERGEABLE) || !vma->anon_vma)
@@ -985,6 +988,7 @@ static int unmerge_and_remove_all_rmap_items(void)
 		}
=20
 		remove_trailing_rmap_items(&mm_slot->rmap_list);
+		rcu_read_unlock();
 		mmap_read_unlock(mm);
=20
 		spin_lock(&ksm_mmlist_lock);
@@ -1008,6 +1012,7 @@ static int unmerge_and_remove_all_rmap_items(void)
 	return 0;
=20
 error:
+	rcu_read_unlock();
 	mmap_read_unlock(mm);
 	spin_lock(&ksm_mmlist_lock);
 	ksm_scan.mm_slot =3D &ksm_mm_head;
@@ -2222,6 +2227,7 @@ static struct rmap_item *scan_get_next_rmap_item(stru=
ct page **page)
 	struct vm_area_struct *vma;
 	struct rmap_item *rmap_item;
 	int nid;
+	MA_STATE(mas, NULL, 0, 0);
=20
 	if (list_empty(&ksm_mm_head.mm_list))
 		return NULL;
@@ -2279,13 +2285,15 @@ static struct rmap_item *scan_get_next_rmap_item(st=
ruct page **page)
 	}
=20
 	mm =3D slot->mm;
+	mas.tree =3D &mm->mm_mt;
+
 	mmap_read_lock(mm);
+	rcu_read_lock();
 	if (ksm_test_exit(mm))
-		vma =3D NULL;
-	else
-		vma =3D find_vma(mm, ksm_scan.address);
+		goto no_vmas;
=20
-	for (; vma; vma =3D vma->vm_next) {
+	mas_set(&mas, ksm_scan.address);
+	mas_for_each(&mas, vma, ULONG_MAX) {
 		if (!(vma->vm_flags & VM_MERGEABLE))
 			continue;
 		if (ksm_scan.address < vma->vm_start)
@@ -2313,6 +2321,7 @@ static struct rmap_item *scan_get_next_rmap_item(stru=
ct page **page)
 					ksm_scan.address +=3D PAGE_SIZE;
 				} else
 					put_page(*page);
+				rcu_read_unlock();
 				mmap_read_unlock(mm);
 				return rmap_item;
 			}
@@ -2323,6 +2332,7 @@ static struct rmap_item *scan_get_next_rmap_item(stru=
ct page **page)
 	}
=20
 	if (ksm_test_exit(mm)) {
+no_vmas:
 		ksm_scan.address =3D 0;
 		ksm_scan.rmap_list =3D &slot->rmap_list;
 	}
@@ -2351,9 +2361,11 @@ static struct rmap_item *scan_get_next_rmap_item(str=
uct page **page)
=20
 		free_mm_slot(slot);
 		clear_bit(MMF_VM_MERGEABLE, &mm->flags);
+		rcu_read_unlock();
 		mmap_read_unlock(mm);
 		mmdrop(mm);
 	} else {
+		rcu_read_unlock();
 		mmap_read_unlock(mm);
 		/*
 		 * mmap_read_unlock(mm) first because after
--=20
2.30.2