[PATCH v2 0/7] add common struct mm_slot and use it in THP and KSM

[PATCH v2 0/7] add common struct mm_slot and use it in THP and KSM

[Qi Zheng]

Hi all,

At present, both THP and KSM module have similar structures mm_slot for
organizing and recording the information required for scanning mm, and
each defines the following exactly the same operation functions:

 - alloc_mm_slot
 - free_mm_slot
 - get_mm_slot
 - insert_to_mm_slots_hash

In order to de-duplicate these codes, this patchset introduces a common
struct mm_slot, and lets THP and KSM to use it.

This series is based on next-20220829.

Comments and suggestions are welcome.

Thanks,
Qi.

Changelog in v1 -> v2:
 - change the names of these mm_slot related operation functions
   (suggested by Andrew)

Qi Zheng (7):
  mm: introduce common struct mm_slot
  mm: thp: convert to use common struct mm_slot
  ksm: remove redundant declarations in ksm.h
  ksm: add the ksm prefix to the names of the ksm private structures
  ksm: convert ksm_mm_slot.mm_list to ksm_mm_slot.mm_node
  ksm: convert ksm_mm_slot.link to ksm_mm_slot.hash
  ksm: convert to use common struct mm_slot

 Documentation/mm/ksm.rst |   2 +-
 include/linux/ksm.h      |   3 -
 mm/khugepaged.c          | 121 ++++++---------
 mm/ksm.c                 | 326 ++++++++++++++++++---------------------
 mm/mm_slot.h             |  55 +++++++
 5 files changed, 260 insertions(+), 247 deletions(-)
 create mode 100644 mm/mm_slot.h

-- 
2.20.1

[PATCH v2 1/7] mm: introduce common struct mm_slot

[Qi Zheng]

At present, both THP and KSM module have similar structures
mm_slot for organizing and recording the information required
for scanning mm, and each defines the following exactly the
same operation functions:

 - alloc_mm_slot
 - free_mm_slot
 - get_mm_slot
 - insert_to_mm_slots_hash

In order to de-duplicate these codes, this patch introduces a
common struct mm_slot, and subsequent patches will let THP and
KSM to use it.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
 mm/mm_slot.h | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 mm/mm_slot.h

diff --git a/mm/mm_slot.h b/mm/mm_slot.h
new file mode 100644
index 000000000000..83f18ed1c4bd
--- /dev/null
+++ b/mm/mm_slot.h
@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#ifndef _LINUX_MM_SLOT_H
+#define _LINUX_MM_SLOT_H
+
+#include <linux/hashtable.h>
+#include <linux/slab.h>
+
+/*
+ * struct mm_slot - hash lookup from mm to mm_slot
+ * @hash: link to the mm_slots hash list
+ * @mm_node: link into the mm_slots list
+ * @mm: the mm that this information is valid for
+ */
+struct mm_slot {
+	struct hlist_node hash;
+	struct list_head mm_node;
+	struct mm_struct *mm;
+};
+
+#define mm_slot_entry(ptr, type, member) \
+	container_of(ptr, type, member)
+
+static inline void *mm_slot_alloc(struct kmem_cache *cache)
+{
+	if (!cache)	/* initialization failed */
+		return NULL;
+	return kmem_cache_zalloc(cache, GFP_KERNEL);
+}
+
+static inline void mm_slot_free(struct kmem_cache *cache, void *objp)
+{
+	kmem_cache_free(cache, objp);
+}
+
+#define mm_slot_lookup(_hashtable, _mm) 				       \
+({									       \
+	struct mm_slot *tmp_slot, *mm_slot = NULL;			       \
+									       \
+	hash_for_each_possible(_hashtable, tmp_slot, hash, (unsigned long)_mm) \
+		if (_mm == tmp_slot->mm) {				       \
+			mm_slot = tmp_slot;				       \
+			break;						       \
+		}							       \
+									       \
+	mm_slot;							       \
+})
+
+#define mm_slot_insert(_hashtable, _mm, _mm_slot)			       \
+({									       \
+	_mm_slot->mm = _mm;						       \
+	hash_add(_hashtable, &_mm_slot->hash, (unsigned long)_mm);	       \
+})
+
+#endif /* _LINUX_MM_SLOT_H */
-- 
2.20.1

[PATCH v2 2/7] mm: thp: convert to use common struct mm_slot

[Qi Zheng]

Rename private struct mm_slot to struct khugepaged_mm_slot and
convert to use common struct mm_slot with no functional change.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
 mm/khugepaged.c | 121 ++++++++++++++++++++----------------------------
 1 file changed, 51 insertions(+), 70 deletions(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index d8e388106322..2d74cf01f694 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -23,6 +23,7 @@
 #include <asm/tlb.h>
 #include <asm/pgalloc.h>
 #include "internal.h"
+#include "mm_slot.h"
 
 enum scan_result {
 	SCAN_FAIL,
@@ -104,17 +105,13 @@ struct collapse_control {
 };
 
 /**
- * struct mm_slot - hash lookup from mm to mm_slot
- * @hash: hash collision list
- * @mm_node: khugepaged scan list headed in khugepaged_scan.mm_head
- * @mm: the mm that this information is valid for
+ * struct khugepaged_mm_slot - khugepaged information per mm that is being scanned
+ * @slot: hash lookup from mm to mm_slot
  * @nr_pte_mapped_thp: number of pte mapped THP
  * @pte_mapped_thp: address array corresponding pte mapped THP
  */
-struct mm_slot {
-	struct hlist_node hash;
-	struct list_head mm_node;
-	struct mm_struct *mm;
+struct khugepaged_mm_slot {
+	struct mm_slot slot;
 
 	/* pte-mapped THP in this mm */
 	int nr_pte_mapped_thp;
@@ -131,7 +128,7 @@ struct mm_slot {
  */
 struct khugepaged_scan {
 	struct list_head mm_head;
-	struct mm_slot *mm_slot;
+	struct khugepaged_mm_slot *mm_slot;
 	unsigned long address;
 };
 
@@ -395,8 +392,9 @@ int hugepage_madvise(struct vm_area_struct *vma,
 int __init khugepaged_init(void)
 {
 	mm_slot_cache = kmem_cache_create("khugepaged_mm_slot",
-					  sizeof(struct mm_slot),
-					  __alignof__(struct mm_slot), 0, NULL);
+					  sizeof(struct khugepaged_mm_slot),
+					  __alignof__(struct khugepaged_mm_slot),
+					  0, NULL);
 	if (!mm_slot_cache)
 		return -ENOMEM;
 
@@ -413,36 +411,6 @@ void __init khugepaged_destroy(void)
 	kmem_cache_destroy(mm_slot_cache);
 }
 
-static inline struct mm_slot *alloc_mm_slot(void)
-{
-	if (!mm_slot_cache)	/* initialization failed */
-		return NULL;
-	return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL);
-}
-
-static inline void free_mm_slot(struct mm_slot *mm_slot)
-{
-	kmem_cache_free(mm_slot_cache, mm_slot);
-}
-
-static struct mm_slot *get_mm_slot(struct mm_struct *mm)
-{
-	struct mm_slot *mm_slot;
-
-	hash_for_each_possible(mm_slots_hash, mm_slot, hash, (unsigned long)mm)
-		if (mm == mm_slot->mm)
-			return mm_slot;
-
-	return NULL;
-}
-
-static void insert_to_mm_slots_hash(struct mm_struct *mm,
-				    struct mm_slot *mm_slot)
-{
-	mm_slot->mm = mm;
-	hash_add(mm_slots_hash, &mm_slot->hash, (long)mm);
-}
-
 static inline int hpage_collapse_test_exit(struct mm_struct *mm)
 {
 	return atomic_read(&mm->mm_users) == 0;
@@ -450,28 +418,31 @@ static inline int hpage_collapse_test_exit(struct mm_struct *mm)
 
 void __khugepaged_enter(struct mm_struct *mm)
 {
-	struct mm_slot *mm_slot;
+	struct khugepaged_mm_slot *mm_slot;
+	struct mm_slot *slot;
 	int wakeup;
 
-	mm_slot = alloc_mm_slot();
+	mm_slot = mm_slot_alloc(mm_slot_cache);
 	if (!mm_slot)
 		return;
 
+	slot = &mm_slot->slot;
+
 	/* __khugepaged_exit() must not run from under us */
 	VM_BUG_ON_MM(hpage_collapse_test_exit(mm), mm);
 	if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) {
-		free_mm_slot(mm_slot);
+		mm_slot_free(mm_slot_cache, mm_slot);
 		return;
 	}
 
 	spin_lock(&khugepaged_mm_lock);
-	insert_to_mm_slots_hash(mm, mm_slot);
+	mm_slot_insert(mm_slots_hash, mm, slot);
 	/*
 	 * Insert just behind the scanning cursor, to let the area settle
 	 * down a little.
 	 */
 	wakeup = list_empty(&khugepaged_scan.mm_head);
-	list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head);
+	list_add_tail(&slot->mm_node, &khugepaged_scan.mm_head);
 	spin_unlock(&khugepaged_mm_lock);
 
 	mmgrab(mm);
@@ -491,21 +462,23 @@ void khugepaged_enter_vma(struct vm_area_struct *vma,
 
 void __khugepaged_exit(struct mm_struct *mm)
 {
-	struct mm_slot *mm_slot;
+	struct khugepaged_mm_slot *mm_slot;
+	struct mm_slot *slot;
 	int free = 0;
 
 	spin_lock(&khugepaged_mm_lock);
-	mm_slot = get_mm_slot(mm);
+	slot = mm_slot_lookup(mm_slots_hash, mm);
+	mm_slot = mm_slot_entry(slot, struct khugepaged_mm_slot, slot);
 	if (mm_slot && khugepaged_scan.mm_slot != mm_slot) {
-		hash_del(&mm_slot->hash);
-		list_del(&mm_slot->mm_node);
+		hash_del(&slot->hash);
+		list_del(&slot->mm_node);
 		free = 1;
 	}
 	spin_unlock(&khugepaged_mm_lock);
 
 	if (free) {
 		clear_bit(MMF_VM_HUGEPAGE, &mm->flags);
-		free_mm_slot(mm_slot);
+		mm_slot_free(mm_slot_cache, mm_slot);
 		mmdrop(mm);
 	} else if (mm_slot) {
 		/*
@@ -1321,16 +1294,17 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm,
 	return result;
 }
 
-static void collect_mm_slot(struct mm_slot *mm_slot)
+static void collect_mm_slot(struct khugepaged_mm_slot *mm_slot)
 {
-	struct mm_struct *mm = mm_slot->mm;
+	struct mm_slot *slot = &mm_slot->slot;
+	struct mm_struct *mm = slot->mm;
 
 	lockdep_assert_held(&khugepaged_mm_lock);
 
 	if (hpage_collapse_test_exit(mm)) {
 		/* free mm_slot */
-		hash_del(&mm_slot->hash);
-		list_del(&mm_slot->mm_node);
+		hash_del(&slot->hash);
+		list_del(&slot->mm_node);
 
 		/*
 		 * Not strictly needed because the mm exited already.
@@ -1339,7 +1313,7 @@ static void collect_mm_slot(struct mm_slot *mm_slot)
 		 */
 
 		/* khugepaged_mm_lock actually not necessary for the below */
-		free_mm_slot(mm_slot);
+		mm_slot_free(mm_slot_cache, mm_slot);
 		mmdrop(mm);
 	}
 }
@@ -1352,12 +1326,14 @@ static void collect_mm_slot(struct mm_slot *mm_slot)
 static void khugepaged_add_pte_mapped_thp(struct mm_struct *mm,
 					  unsigned long addr)
 {
-	struct mm_slot *mm_slot;
+	struct khugepaged_mm_slot *mm_slot;
+	struct mm_slot *slot;
 
 	VM_BUG_ON(addr & ~HPAGE_PMD_MASK);
 
 	spin_lock(&khugepaged_mm_lock);
-	mm_slot = get_mm_slot(mm);
+	slot = mm_slot_lookup(mm_slots_hash, mm);
+	mm_slot = mm_slot_entry(slot, struct khugepaged_mm_slot, slot);
 	if (likely(mm_slot && mm_slot->nr_pte_mapped_thp < MAX_PTE_MAPPED_THP))
 		mm_slot->pte_mapped_thp[mm_slot->nr_pte_mapped_thp++] = addr;
 	spin_unlock(&khugepaged_mm_lock);
@@ -1489,9 +1465,10 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr)
 	goto drop_hpage;
 }
 
-static void khugepaged_collapse_pte_mapped_thps(struct mm_slot *mm_slot)
+static void khugepaged_collapse_pte_mapped_thps(struct khugepaged_mm_slot *mm_slot)
 {
-	struct mm_struct *mm = mm_slot->mm;
+	struct mm_slot *slot = &mm_slot->slot;
+	struct mm_struct *mm = slot->mm;
 	int i;
 
 	if (likely(mm_slot->nr_pte_mapped_thp == 0))
@@ -2054,7 +2031,8 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
 	__acquires(&khugepaged_mm_lock)
 {
 	struct vma_iterator vmi;
-	struct mm_slot *mm_slot;
+	struct khugepaged_mm_slot *mm_slot;
+	struct mm_slot *slot;
 	struct mm_struct *mm;
 	struct vm_area_struct *vma;
 	int progress = 0;
@@ -2064,18 +2042,20 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
 	lockdep_assert_held(&khugepaged_mm_lock);
 	*result = SCAN_FAIL;
 
-	if (khugepaged_scan.mm_slot)
+	if (khugepaged_scan.mm_slot) {
 		mm_slot = khugepaged_scan.mm_slot;
-	else {
-		mm_slot = list_entry(khugepaged_scan.mm_head.next,
+		slot = &mm_slot->slot;
+	} else {
+		slot = list_entry(khugepaged_scan.mm_head.next,
 				     struct mm_slot, mm_node);
+		mm_slot = mm_slot_entry(slot, struct khugepaged_mm_slot, slot);
 		khugepaged_scan.address = 0;
 		khugepaged_scan.mm_slot = mm_slot;
 	}
 	spin_unlock(&khugepaged_mm_lock);
 	khugepaged_collapse_pte_mapped_thps(mm_slot);
 
-	mm = mm_slot->mm;
+	mm = slot->mm;
 	/*
 	 * Don't wait for semaphore (to avoid long wait times).  Just move to
 	 * the next mm on the list.
@@ -2171,10 +2151,11 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
 		 * khugepaged runs here, khugepaged_exit will find
 		 * mm_slot not pointing to the exiting mm.
 		 */
-		if (mm_slot->mm_node.next != &khugepaged_scan.mm_head) {
-			khugepaged_scan.mm_slot = list_entry(
-				mm_slot->mm_node.next,
-				struct mm_slot, mm_node);
+		if (slot->mm_node.next != &khugepaged_scan.mm_head) {
+			slot = list_entry(slot->mm_node.next,
+					  struct mm_slot, mm_node);
+			khugepaged_scan.mm_slot =
+				mm_slot_entry(slot, struct khugepaged_mm_slot, slot);
 			khugepaged_scan.address = 0;
 		} else {
 			khugepaged_scan.mm_slot = NULL;
@@ -2269,7 +2250,7 @@ static void khugepaged_wait_work(void)
 
 static int khugepaged(void *none)
 {
-	struct mm_slot *mm_slot;
+	struct khugepaged_mm_slot *mm_slot;
 
 	set_freezable();
 	set_user_nice(current, MAX_NICE);
-- 
2.20.1

[PATCH v2 3/7] ksm: remove redundant declarations in ksm.h

[Qi Zheng]

Currently, for struct stable_node, no one uses it in both the
include/linux/ksm.h file and the file that contains it. For
struct mem_cgroup, it's also not used in ksm.h. So they're all
redundant, just remove them.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
 include/linux/ksm.h | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/include/linux/ksm.h b/include/linux/ksm.h
index 0b4f17418f64..7e232ba59b86 100644
--- a/include/linux/ksm.h
+++ b/include/linux/ksm.h
@@ -15,9 +15,6 @@
 #include <linux/sched.h>
 #include <linux/sched/coredump.h>
 
-struct stable_node;
-struct mem_cgroup;
-
 #ifdef CONFIG_KSM
 int ksm_madvise(struct vm_area_struct *vma, unsigned long start,
 		unsigned long end, int advice, unsigned long *vm_flags);
-- 
2.20.1

[PATCH v2 4/7] ksm: add the ksm prefix to the names of the ksm private structures

[Qi Zheng]

In order to prevent the name of the private structure of ksm
from being the same as the name of the common structure used
in subsequent patches, prefix their names with ksm in advance.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
 Documentation/mm/ksm.rst |   2 +-
 mm/ksm.c                 | 216 +++++++++++++++++++--------------------
 2 files changed, 109 insertions(+), 109 deletions(-)

diff --git a/Documentation/mm/ksm.rst b/Documentation/mm/ksm.rst
index 9e37add068e6..f83cfbc12f4c 100644
--- a/Documentation/mm/ksm.rst
+++ b/Documentation/mm/ksm.rst
@@ -26,7 +26,7 @@ tree.
 
 If a KSM page is shared between less than ``max_page_sharing`` VMAs,
 the node of the stable tree that represents such KSM page points to a
-list of struct rmap_item and the ``page->mapping`` of the
+list of struct ksm_rmap_item and the ``page->mapping`` of the
 KSM page points to the stable tree node.
 
 When the sharing passes this threshold, KSM adds a second dimension to
diff --git a/mm/ksm.c b/mm/ksm.c
index e34cc21d5556..3937111f9ab8 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -82,7 +82,7 @@
  *   different KSM page copy of that content
  *
  * Internally, the regular nodes, "dups" and "chains" are represented
- * using the same struct stable_node structure.
+ * using the same struct ksm_stable_node structure.
  *
  * In addition to the stable tree, KSM uses a second data structure called the
  * unstable tree: this tree holds pointers to pages which have been found to
@@ -112,16 +112,16 @@
  */
 
 /**
- * struct mm_slot - ksm information per mm that is being scanned
+ * struct ksm_mm_slot - ksm information per mm that is being scanned
  * @link: link to the mm_slots hash list
  * @mm_list: link into the mm_slots list, rooted in ksm_mm_head
  * @rmap_list: head for this mm_slot's singly-linked list of rmap_items
  * @mm: the mm that this information is valid for
  */
-struct mm_slot {
+struct ksm_mm_slot {
 	struct hlist_node link;
 	struct list_head mm_list;
-	struct rmap_item *rmap_list;
+	struct ksm_rmap_item *rmap_list;
 	struct mm_struct *mm;
 };
 
@@ -135,14 +135,14 @@ struct mm_slot {
  * There is only the one ksm_scan instance of this cursor structure.
  */
 struct ksm_scan {
-	struct mm_slot *mm_slot;
+	struct ksm_mm_slot *mm_slot;
 	unsigned long address;
-	struct rmap_item **rmap_list;
+	struct ksm_rmap_item **rmap_list;
 	unsigned long seqnr;
 };
 
 /**
- * struct stable_node - node of the stable rbtree
+ * struct ksm_stable_node - node of the stable rbtree
  * @node: rb node of this ksm page in the stable tree
  * @head: (overlaying parent) &migrate_nodes indicates temporarily on that list
  * @hlist_dup: linked into the stable_node->hlist with a stable_node chain
@@ -153,7 +153,7 @@ struct ksm_scan {
  * @rmap_hlist_len: number of rmap_item entries in hlist or STABLE_NODE_CHAIN
  * @nid: NUMA node id of stable tree in which linked (may not match kpfn)
  */
-struct stable_node {
+struct ksm_stable_node {
 	union {
 		struct rb_node node;	/* when node of stable tree */
 		struct {		/* when listed for migration */
@@ -182,7 +182,7 @@ struct stable_node {
 };
 
 /**
- * struct rmap_item - reverse mapping item for virtual addresses
+ * struct ksm_rmap_item - reverse mapping item for virtual addresses
  * @rmap_list: next rmap_item in mm_slot's singly-linked rmap_list
  * @anon_vma: pointer to anon_vma for this mm,address, when in stable tree
  * @nid: NUMA node id of unstable tree in which linked (may not match page)
@@ -193,8 +193,8 @@ struct stable_node {
  * @head: pointer to stable_node heading this list in the stable tree
  * @hlist: link into hlist of rmap_items hanging off that stable_node
  */
-struct rmap_item {
-	struct rmap_item *rmap_list;
+struct ksm_rmap_item {
+	struct ksm_rmap_item *rmap_list;
 	union {
 		struct anon_vma *anon_vma;	/* when stable */
 #ifdef CONFIG_NUMA
@@ -207,7 +207,7 @@ struct rmap_item {
 	union {
 		struct rb_node node;	/* when node of unstable tree */
 		struct {		/* when listed from stable tree */
-			struct stable_node *head;
+			struct ksm_stable_node *head;
 			struct hlist_node hlist;
 		};
 	};
@@ -230,7 +230,7 @@ static LIST_HEAD(migrate_nodes);
 #define MM_SLOTS_HASH_BITS 10
 static DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS);
 
-static struct mm_slot ksm_mm_head = {
+static struct ksm_mm_slot ksm_mm_head = {
 	.mm_list = LIST_HEAD_INIT(ksm_mm_head.mm_list),
 };
 static struct ksm_scan ksm_scan = {
@@ -298,21 +298,21 @@ static DECLARE_WAIT_QUEUE_HEAD(ksm_iter_wait);
 static DEFINE_MUTEX(ksm_thread_mutex);
 static DEFINE_SPINLOCK(ksm_mmlist_lock);
 
-#define KSM_KMEM_CACHE(__struct, __flags) kmem_cache_create("ksm_"#__struct,\
+#define KSM_KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
 		sizeof(struct __struct), __alignof__(struct __struct),\
 		(__flags), NULL)
 
 static int __init ksm_slab_init(void)
 {
-	rmap_item_cache = KSM_KMEM_CACHE(rmap_item, 0);
+	rmap_item_cache = KSM_KMEM_CACHE(ksm_rmap_item, 0);
 	if (!rmap_item_cache)
 		goto out;
 
-	stable_node_cache = KSM_KMEM_CACHE(stable_node, 0);
+	stable_node_cache = KSM_KMEM_CACHE(ksm_stable_node, 0);
 	if (!stable_node_cache)
 		goto out_free1;
 
-	mm_slot_cache = KSM_KMEM_CACHE(mm_slot, 0);
+	mm_slot_cache = KSM_KMEM_CACHE(ksm_mm_slot, 0);
 	if (!mm_slot_cache)
 		goto out_free2;
 
@@ -334,18 +334,18 @@ static void __init ksm_slab_free(void)
 	mm_slot_cache = NULL;
 }
 
-static __always_inline bool is_stable_node_chain(struct stable_node *chain)
+static __always_inline bool is_stable_node_chain(struct ksm_stable_node *chain)
 {
 	return chain->rmap_hlist_len == STABLE_NODE_CHAIN;
 }
 
-static __always_inline bool is_stable_node_dup(struct stable_node *dup)
+static __always_inline bool is_stable_node_dup(struct ksm_stable_node *dup)
 {
 	return dup->head == STABLE_NODE_DUP_HEAD;
 }
 
-static inline void stable_node_chain_add_dup(struct stable_node *dup,
-					     struct stable_node *chain)
+static inline void stable_node_chain_add_dup(struct ksm_stable_node *dup,
+					     struct ksm_stable_node *chain)
 {
 	VM_BUG_ON(is_stable_node_dup(dup));
 	dup->head = STABLE_NODE_DUP_HEAD;
@@ -354,14 +354,14 @@ static inline void stable_node_chain_add_dup(struct stable_node *dup,
 	ksm_stable_node_dups++;
 }
 
-static inline void __stable_node_dup_del(struct stable_node *dup)
+static inline void __stable_node_dup_del(struct ksm_stable_node *dup)
 {
 	VM_BUG_ON(!is_stable_node_dup(dup));
 	hlist_del(&dup->hlist_dup);
 	ksm_stable_node_dups--;
 }
 
-static inline void stable_node_dup_del(struct stable_node *dup)
+static inline void stable_node_dup_del(struct ksm_stable_node *dup)
 {
 	VM_BUG_ON(is_stable_node_chain(dup));
 	if (is_stable_node_dup(dup))
@@ -373,9 +373,9 @@ static inline void stable_node_dup_del(struct stable_node *dup)
 #endif
 }
 
-static inline struct rmap_item *alloc_rmap_item(void)
+static inline struct ksm_rmap_item *alloc_rmap_item(void)
 {
-	struct rmap_item *rmap_item;
+	struct ksm_rmap_item *rmap_item;
 
 	rmap_item = kmem_cache_zalloc(rmap_item_cache, GFP_KERNEL |
 						__GFP_NORETRY | __GFP_NOWARN);
@@ -384,14 +384,14 @@ static inline struct rmap_item *alloc_rmap_item(void)
 	return rmap_item;
 }
 
-static inline void free_rmap_item(struct rmap_item *rmap_item)
+static inline void free_rmap_item(struct ksm_rmap_item *rmap_item)
 {
 	ksm_rmap_items--;
 	rmap_item->mm = NULL;	/* debug safety */
 	kmem_cache_free(rmap_item_cache, rmap_item);
 }
 
-static inline struct stable_node *alloc_stable_node(void)
+static inline struct ksm_stable_node *alloc_stable_node(void)
 {
 	/*
 	 * The allocation can take too long with GFP_KERNEL when memory is under
@@ -401,28 +401,28 @@ static inline struct stable_node *alloc_stable_node(void)
 	return kmem_cache_alloc(stable_node_cache, GFP_KERNEL | __GFP_HIGH);
 }
 
-static inline void free_stable_node(struct stable_node *stable_node)
+static inline void free_stable_node(struct ksm_stable_node *stable_node)
 {
 	VM_BUG_ON(stable_node->rmap_hlist_len &&
 		  !is_stable_node_chain(stable_node));
 	kmem_cache_free(stable_node_cache, stable_node);
 }
 
-static inline struct mm_slot *alloc_mm_slot(void)
+static inline struct ksm_mm_slot *alloc_mm_slot(void)
 {
 	if (!mm_slot_cache)	/* initialization failed */
 		return NULL;
 	return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL);
 }
 
-static inline void free_mm_slot(struct mm_slot *mm_slot)
+static inline void free_mm_slot(struct ksm_mm_slot *mm_slot)
 {
 	kmem_cache_free(mm_slot_cache, mm_slot);
 }
 
-static struct mm_slot *get_mm_slot(struct mm_struct *mm)
+static struct ksm_mm_slot *get_mm_slot(struct mm_struct *mm)
 {
-	struct mm_slot *slot;
+	struct ksm_mm_slot *slot;
 
 	hash_for_each_possible(mm_slots_hash, slot, link, (unsigned long)mm)
 		if (slot->mm == mm)
@@ -432,7 +432,7 @@ static struct mm_slot *get_mm_slot(struct mm_struct *mm)
 }
 
 static void insert_to_mm_slots_hash(struct mm_struct *mm,
-				    struct mm_slot *mm_slot)
+				    struct ksm_mm_slot *mm_slot)
 {
 	mm_slot->mm = mm;
 	hash_add(mm_slots_hash, &mm_slot->link, (unsigned long)mm);
@@ -528,7 +528,7 @@ static struct vm_area_struct *find_mergeable_vma(struct mm_struct *mm,
 	return vma;
 }
 
-static void break_cow(struct rmap_item *rmap_item)
+static void break_cow(struct ksm_rmap_item *rmap_item)
 {
 	struct mm_struct *mm = rmap_item->mm;
 	unsigned long addr = rmap_item->address;
@@ -547,7 +547,7 @@ static void break_cow(struct rmap_item *rmap_item)
 	mmap_read_unlock(mm);
 }
 
-static struct page *get_mergeable_page(struct rmap_item *rmap_item)
+static struct page *get_mergeable_page(struct ksm_rmap_item *rmap_item)
 {
 	struct mm_struct *mm = rmap_item->mm;
 	unsigned long addr = rmap_item->address;
@@ -588,10 +588,10 @@ static inline int get_kpfn_nid(unsigned long kpfn)
 	return ksm_merge_across_nodes ? 0 : NUMA(pfn_to_nid(kpfn));
 }
 
-static struct stable_node *alloc_stable_node_chain(struct stable_node *dup,
+static struct ksm_stable_node *alloc_stable_node_chain(struct ksm_stable_node *dup,
 						   struct rb_root *root)
 {
-	struct stable_node *chain = alloc_stable_node();
+	struct ksm_stable_node *chain = alloc_stable_node();
 	VM_BUG_ON(is_stable_node_chain(dup));
 	if (likely(chain)) {
 		INIT_HLIST_HEAD(&chain->hlist);
@@ -621,7 +621,7 @@ static struct stable_node *alloc_stable_node_chain(struct stable_node *dup,
 	return chain;
 }
 
-static inline void free_stable_node_chain(struct stable_node *chain,
+static inline void free_stable_node_chain(struct ksm_stable_node *chain,
 					  struct rb_root *root)
 {
 	rb_erase(&chain->node, root);
@@ -629,9 +629,9 @@ static inline void free_stable_node_chain(struct stable_node *chain,
 	ksm_stable_node_chains--;
 }
 
-static void remove_node_from_stable_tree(struct stable_node *stable_node)
+static void remove_node_from_stable_tree(struct ksm_stable_node *stable_node)
 {
-	struct rmap_item *rmap_item;
+	struct ksm_rmap_item *rmap_item;
 
 	/* check it's not STABLE_NODE_CHAIN or negative */
 	BUG_ON(stable_node->rmap_hlist_len < 0);
@@ -693,7 +693,7 @@ enum get_ksm_page_flags {
  * a page to put something that might look like our key in page->mapping.
  * is on its way to being freed; but it is an anomaly to bear in mind.
  */
-static struct page *get_ksm_page(struct stable_node *stable_node,
+static struct page *get_ksm_page(struct ksm_stable_node *stable_node,
 				 enum get_ksm_page_flags flags)
 {
 	struct page *page;
@@ -772,10 +772,10 @@ static struct page *get_ksm_page(struct stable_node *stable_node,
  * Removing rmap_item from stable or unstable tree.
  * This function will clean the information from the stable/unstable tree.
  */
-static void remove_rmap_item_from_tree(struct rmap_item *rmap_item)
+static void remove_rmap_item_from_tree(struct ksm_rmap_item *rmap_item)
 {
 	if (rmap_item->address & STABLE_FLAG) {
-		struct stable_node *stable_node;
+		struct ksm_stable_node *stable_node;
 		struct page *page;
 
 		stable_node = rmap_item->head;
@@ -822,10 +822,10 @@ static void remove_rmap_item_from_tree(struct rmap_item *rmap_item)
 	cond_resched();		/* we're called from many long loops */
 }
 
-static void remove_trailing_rmap_items(struct rmap_item **rmap_list)
+static void remove_trailing_rmap_items(struct ksm_rmap_item **rmap_list)
 {
 	while (*rmap_list) {
-		struct rmap_item *rmap_item = *rmap_list;
+		struct ksm_rmap_item *rmap_item = *rmap_list;
 		*rmap_list = rmap_item->rmap_list;
 		remove_rmap_item_from_tree(rmap_item);
 		free_rmap_item(rmap_item);
@@ -862,18 +862,18 @@ static int unmerge_ksm_pages(struct vm_area_struct *vma,
 	return err;
 }
 
-static inline struct stable_node *folio_stable_node(struct folio *folio)
+static inline struct ksm_stable_node *folio_stable_node(struct folio *folio)
 {
 	return folio_test_ksm(folio) ? folio_raw_mapping(folio) : NULL;
 }
 
-static inline struct stable_node *page_stable_node(struct page *page)
+static inline struct ksm_stable_node *page_stable_node(struct page *page)
 {
 	return folio_stable_node(page_folio(page));
 }
 
 static inline void set_page_stable_node(struct page *page,
-					struct stable_node *stable_node)
+					struct ksm_stable_node *stable_node)
 {
 	VM_BUG_ON_PAGE(PageAnon(page) && PageAnonExclusive(page), page);
 	page->mapping = (void *)((unsigned long)stable_node | PAGE_MAPPING_KSM);
@@ -883,7 +883,7 @@ static inline void set_page_stable_node(struct page *page,
 /*
  * Only called through the sysfs control interface:
  */
-static int remove_stable_node(struct stable_node *stable_node)
+static int remove_stable_node(struct ksm_stable_node *stable_node)
 {
 	struct page *page;
 	int err;
@@ -921,10 +921,10 @@ static int remove_stable_node(struct stable_node *stable_node)
 	return err;
 }
 
-static int remove_stable_node_chain(struct stable_node *stable_node,
+static int remove_stable_node_chain(struct ksm_stable_node *stable_node,
 				    struct rb_root *root)
 {
-	struct stable_node *dup;
+	struct ksm_stable_node *dup;
 	struct hlist_node *hlist_safe;
 
 	if (!is_stable_node_chain(stable_node)) {
@@ -948,14 +948,14 @@ static int remove_stable_node_chain(struct stable_node *stable_node,
 
 static int remove_all_stable_nodes(void)
 {
-	struct stable_node *stable_node, *next;
+	struct ksm_stable_node *stable_node, *next;
 	int nid;
 	int err = 0;
 
 	for (nid = 0; nid < ksm_nr_node_ids; nid++) {
 		while (root_stable_tree[nid].rb_node) {
 			stable_node = rb_entry(root_stable_tree[nid].rb_node,
-						struct stable_node, node);
+						struct ksm_stable_node, node);
 			if (remove_stable_node_chain(stable_node,
 						     root_stable_tree + nid)) {
 				err = -EBUSY;
@@ -974,14 +974,14 @@ static int remove_all_stable_nodes(void)
 
 static int unmerge_and_remove_all_rmap_items(void)
 {
-	struct mm_slot *mm_slot;
+	struct ksm_mm_slot *mm_slot;
 	struct mm_struct *mm;
 	struct vm_area_struct *vma;
 	int err = 0;
 
 	spin_lock(&ksm_mmlist_lock);
 	ksm_scan.mm_slot = list_entry(ksm_mm_head.mm_list.next,
-						struct mm_slot, mm_list);
+						struct ksm_mm_slot, mm_list);
 	spin_unlock(&ksm_mmlist_lock);
 
 	for (mm_slot = ksm_scan.mm_slot; mm_slot != &ksm_mm_head;
@@ -1006,7 +1006,7 @@ static int unmerge_and_remove_all_rmap_items(void)
 
 		spin_lock(&ksm_mmlist_lock);
 		ksm_scan.mm_slot = list_entry(mm_slot->mm_list.next,
-						struct mm_slot, mm_list);
+						struct ksm_mm_slot, mm_list);
 		if (ksm_test_exit(mm)) {
 			hash_del(&mm_slot->link);
 			list_del(&mm_slot->mm_list);
@@ -1293,7 +1293,7 @@ static int try_to_merge_one_page(struct vm_area_struct *vma,
  *
  * This function returns 0 if the pages were merged, -EFAULT otherwise.
  */
-static int try_to_merge_with_ksm_page(struct rmap_item *rmap_item,
+static int try_to_merge_with_ksm_page(struct ksm_rmap_item *rmap_item,
 				      struct page *page, struct page *kpage)
 {
 	struct mm_struct *mm = rmap_item->mm;
@@ -1330,9 +1330,9 @@ static int try_to_merge_with_ksm_page(struct rmap_item *rmap_item,
  * Note that this function upgrades page to ksm page: if one of the pages
  * is already a ksm page, try_to_merge_with_ksm_page should be used.
  */
-static struct page *try_to_merge_two_pages(struct rmap_item *rmap_item,
+static struct page *try_to_merge_two_pages(struct ksm_rmap_item *rmap_item,
 					   struct page *page,
-					   struct rmap_item *tree_rmap_item,
+					   struct ksm_rmap_item *tree_rmap_item,
 					   struct page *tree_page)
 {
 	int err;
@@ -1352,7 +1352,7 @@ static struct page *try_to_merge_two_pages(struct rmap_item *rmap_item,
 }
 
 static __always_inline
-bool __is_page_sharing_candidate(struct stable_node *stable_node, int offset)
+bool __is_page_sharing_candidate(struct ksm_stable_node *stable_node, int offset)
 {
 	VM_BUG_ON(stable_node->rmap_hlist_len < 0);
 	/*
@@ -1366,17 +1366,17 @@ bool __is_page_sharing_candidate(struct stable_node *stable_node, int offset)
 }
 
 static __always_inline
-bool is_page_sharing_candidate(struct stable_node *stable_node)
+bool is_page_sharing_candidate(struct ksm_stable_node *stable_node)
 {
 	return __is_page_sharing_candidate(stable_node, 0);
 }
 
-static struct page *stable_node_dup(struct stable_node **_stable_node_dup,
-				    struct stable_node **_stable_node,
+static struct page *stable_node_dup(struct ksm_stable_node **_stable_node_dup,
+				    struct ksm_stable_node **_stable_node,
 				    struct rb_root *root,
 				    bool prune_stale_stable_nodes)
 {
-	struct stable_node *dup, *found = NULL, *stable_node = *_stable_node;
+	struct ksm_stable_node *dup, *found = NULL, *stable_node = *_stable_node;
 	struct hlist_node *hlist_safe;
 	struct page *_tree_page, *tree_page = NULL;
 	int nr = 0;
@@ -1490,7 +1490,7 @@ static struct page *stable_node_dup(struct stable_node **_stable_node_dup,
 	return tree_page;
 }
 
-static struct stable_node *stable_node_dup_any(struct stable_node *stable_node,
+static struct ksm_stable_node *stable_node_dup_any(struct ksm_stable_node *stable_node,
 					       struct rb_root *root)
 {
 	if (!is_stable_node_chain(stable_node))
@@ -1517,12 +1517,12 @@ static struct stable_node *stable_node_dup_any(struct stable_node *stable_node,
  * function and will be overwritten in all cases, the caller doesn't
  * need to initialize it.
  */
-static struct page *__stable_node_chain(struct stable_node **_stable_node_dup,
-					struct stable_node **_stable_node,
+static struct page *__stable_node_chain(struct ksm_stable_node **_stable_node_dup,
+					struct ksm_stable_node **_stable_node,
 					struct rb_root *root,
 					bool prune_stale_stable_nodes)
 {
-	struct stable_node *stable_node = *_stable_node;
+	struct ksm_stable_node *stable_node = *_stable_node;
 	if (!is_stable_node_chain(stable_node)) {
 		if (is_page_sharing_candidate(stable_node)) {
 			*_stable_node_dup = stable_node;
@@ -1539,18 +1539,18 @@ static struct page *__stable_node_chain(struct stable_node **_stable_node_dup,
 			       prune_stale_stable_nodes);
 }
 
-static __always_inline struct page *chain_prune(struct stable_node **s_n_d,
-						struct stable_node **s_n,
+static __always_inline struct page *chain_prune(struct ksm_stable_node **s_n_d,
+						struct ksm_stable_node **s_n,
 						struct rb_root *root)
 {
 	return __stable_node_chain(s_n_d, s_n, root, true);
 }
 
-static __always_inline struct page *chain(struct stable_node **s_n_d,
-					  struct stable_node *s_n,
+static __always_inline struct page *chain(struct ksm_stable_node **s_n_d,
+					  struct ksm_stable_node *s_n,
 					  struct rb_root *root)
 {
-	struct stable_node *old_stable_node = s_n;
+	struct ksm_stable_node *old_stable_node = s_n;
 	struct page *tree_page;
 
 	tree_page = __stable_node_chain(s_n_d, &s_n, root, false);
@@ -1574,8 +1574,8 @@ static struct page *stable_tree_search(struct page *page)
 	struct rb_root *root;
 	struct rb_node **new;
 	struct rb_node *parent;
-	struct stable_node *stable_node, *stable_node_dup, *stable_node_any;
-	struct stable_node *page_node;
+	struct ksm_stable_node *stable_node, *stable_node_dup, *stable_node_any;
+	struct ksm_stable_node *page_node;
 
 	page_node = page_stable_node(page);
 	if (page_node && page_node->head != &migrate_nodes) {
@@ -1595,7 +1595,7 @@ static struct page *stable_tree_search(struct page *page)
 		int ret;
 
 		cond_resched();
-		stable_node = rb_entry(*new, struct stable_node, node);
+		stable_node = rb_entry(*new, struct ksm_stable_node, node);
 		stable_node_any = NULL;
 		tree_page = chain_prune(&stable_node_dup, &stable_node,	root);
 		/*
@@ -1818,14 +1818,14 @@ static struct page *stable_tree_search(struct page *page)
  * This function returns the stable tree node just allocated on success,
  * NULL otherwise.
  */
-static struct stable_node *stable_tree_insert(struct page *kpage)
+static struct ksm_stable_node *stable_tree_insert(struct page *kpage)
 {
 	int nid;
 	unsigned long kpfn;
 	struct rb_root *root;
 	struct rb_node **new;
 	struct rb_node *parent;
-	struct stable_node *stable_node, *stable_node_dup, *stable_node_any;
+	struct ksm_stable_node *stable_node, *stable_node_dup, *stable_node_any;
 	bool need_chain = false;
 
 	kpfn = page_to_pfn(kpage);
@@ -1840,7 +1840,7 @@ static struct stable_node *stable_tree_insert(struct page *kpage)
 		int ret;
 
 		cond_resched();
-		stable_node = rb_entry(*new, struct stable_node, node);
+		stable_node = rb_entry(*new, struct ksm_stable_node, node);
 		stable_node_any = NULL;
 		tree_page = chain(&stable_node_dup, stable_node, root);
 		if (!stable_node_dup) {
@@ -1909,7 +1909,7 @@ static struct stable_node *stable_tree_insert(struct page *kpage)
 		rb_insert_color(&stable_node_dup->node, root);
 	} else {
 		if (!is_stable_node_chain(stable_node)) {
-			struct stable_node *orig = stable_node;
+			struct ksm_stable_node *orig = stable_node;
 			/* chain is missing so create it */
 			stable_node = alloc_stable_node_chain(orig, root);
 			if (!stable_node) {
@@ -1938,7 +1938,7 @@ static struct stable_node *stable_tree_insert(struct page *kpage)
  * the same walking algorithm in an rbtree.
  */
 static
-struct rmap_item *unstable_tree_search_insert(struct rmap_item *rmap_item,
+struct ksm_rmap_item *unstable_tree_search_insert(struct ksm_rmap_item *rmap_item,
 					      struct page *page,
 					      struct page **tree_pagep)
 {
@@ -1952,12 +1952,12 @@ struct rmap_item *unstable_tree_search_insert(struct rmap_item *rmap_item,
 	new = &root->rb_node;
 
 	while (*new) {
-		struct rmap_item *tree_rmap_item;
+		struct ksm_rmap_item *tree_rmap_item;
 		struct page *tree_page;
 		int ret;
 
 		cond_resched();
-		tree_rmap_item = rb_entry(*new, struct rmap_item, node);
+		tree_rmap_item = rb_entry(*new, struct ksm_rmap_item, node);
 		tree_page = get_mergeable_page(tree_rmap_item);
 		if (!tree_page)
 			return NULL;
@@ -2009,8 +2009,8 @@ struct rmap_item *unstable_tree_search_insert(struct rmap_item *rmap_item,
  * rmap_items hanging off a given node of the stable tree, all sharing
  * the same ksm page.
  */
-static void stable_tree_append(struct rmap_item *rmap_item,
-			       struct stable_node *stable_node,
+static void stable_tree_append(struct ksm_rmap_item *rmap_item,
+			       struct ksm_stable_node *stable_node,
 			       bool max_page_sharing_bypass)
 {
 	/*
@@ -2052,12 +2052,12 @@ static void stable_tree_append(struct rmap_item *rmap_item,
  * @page: the page that we are searching identical page to.
  * @rmap_item: the reverse mapping into the virtual address of this page
  */
-static void cmp_and_merge_page(struct page *page, struct rmap_item *rmap_item)
+static void cmp_and_merge_page(struct page *page, struct ksm_rmap_item *rmap_item)
 {
 	struct mm_struct *mm = rmap_item->mm;
-	struct rmap_item *tree_rmap_item;
+	struct ksm_rmap_item *tree_rmap_item;
 	struct page *tree_page = NULL;
-	struct stable_node *stable_node;
+	struct ksm_stable_node *stable_node;
 	struct page *kpage;
 	unsigned int checksum;
 	int err;
@@ -2213,11 +2213,11 @@ static void cmp_and_merge_page(struct page *page, struct rmap_item *rmap_item)
 	}
 }
 
-static struct rmap_item *get_next_rmap_item(struct mm_slot *mm_slot,
-					    struct rmap_item **rmap_list,
+static struct ksm_rmap_item *get_next_rmap_item(struct ksm_mm_slot *mm_slot,
+					    struct ksm_rmap_item **rmap_list,
 					    unsigned long addr)
 {
-	struct rmap_item *rmap_item;
+	struct ksm_rmap_item *rmap_item;
 
 	while (*rmap_list) {
 		rmap_item = *rmap_list;
@@ -2241,12 +2241,12 @@ static struct rmap_item *get_next_rmap_item(struct mm_slot *mm_slot,
 	return rmap_item;
 }
 
-static struct rmap_item *scan_get_next_rmap_item(struct page **page)
+static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
 {
 	struct mm_struct *mm;
-	struct mm_slot *slot;
+	struct ksm_mm_slot *slot;
 	struct vm_area_struct *vma;
-	struct rmap_item *rmap_item;
+	struct ksm_rmap_item *rmap_item;
 	struct vma_iterator vmi;
 	int nid;
 
@@ -2274,7 +2274,7 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page)
 		 * so prune them once before each full scan.
 		 */
 		if (!ksm_merge_across_nodes) {
-			struct stable_node *stable_node, *next;
+			struct ksm_stable_node *stable_node, *next;
 			struct page *page;
 
 			list_for_each_entry_safe(stable_node, next,
@@ -2291,7 +2291,7 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page)
 			root_unstable_tree[nid] = RB_ROOT;
 
 		spin_lock(&ksm_mmlist_lock);
-		slot = list_entry(slot->mm_list.next, struct mm_slot, mm_list);
+		slot = list_entry(slot->mm_list.next, struct ksm_mm_slot, mm_list);
 		ksm_scan.mm_slot = slot;
 		spin_unlock(&ksm_mmlist_lock);
 		/*
@@ -2365,7 +2365,7 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page)
 
 	spin_lock(&ksm_mmlist_lock);
 	ksm_scan.mm_slot = list_entry(slot->mm_list.next,
-						struct mm_slot, mm_list);
+						struct ksm_mm_slot, mm_list);
 	if (ksm_scan.address == 0) {
 		/*
 		 * We've completed a full scan of all vmas, holding mmap_lock
@@ -2411,7 +2411,7 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page)
  */
 static void ksm_do_scan(unsigned int scan_npages)
 {
-	struct rmap_item *rmap_item;
+	struct ksm_rmap_item *rmap_item;
 	struct page *page;
 
 	while (scan_npages-- && likely(!freezing(current))) {
@@ -2515,7 +2515,7 @@ EXPORT_SYMBOL_GPL(ksm_madvise);
 
 int __ksm_enter(struct mm_struct *mm)
 {
-	struct mm_slot *mm_slot;
+	struct ksm_mm_slot *mm_slot;
 	int needs_wakeup;
 
 	mm_slot = alloc_mm_slot();
@@ -2554,7 +2554,7 @@ int __ksm_enter(struct mm_struct *mm)
 
 void __ksm_exit(struct mm_struct *mm)
 {
-	struct mm_slot *mm_slot;
+	struct ksm_mm_slot *mm_slot;
 	int easy_to_free = 0;
 
 	/*
@@ -2632,8 +2632,8 @@ struct page *ksm_might_need_to_copy(struct page *page,
 
 void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc)
 {
-	struct stable_node *stable_node;
-	struct rmap_item *rmap_item;
+	struct ksm_stable_node *stable_node;
+	struct ksm_rmap_item *rmap_item;
 	int search_new_forks = 0;
 
 	VM_BUG_ON_FOLIO(!folio_test_ksm(folio), folio);
@@ -2703,7 +2703,7 @@ void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc)
 #ifdef CONFIG_MIGRATION
 void folio_migrate_ksm(struct folio *newfolio, struct folio *folio)
 {
-	struct stable_node *stable_node;
+	struct ksm_stable_node *stable_node;
 
 	VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
 	VM_BUG_ON_FOLIO(!folio_test_locked(newfolio), newfolio);
@@ -2736,7 +2736,7 @@ static void wait_while_offlining(void)
 	}
 }
 
-static bool stable_node_dup_remove_range(struct stable_node *stable_node,
+static bool stable_node_dup_remove_range(struct ksm_stable_node *stable_node,
 					 unsigned long start_pfn,
 					 unsigned long end_pfn)
 {
@@ -2752,12 +2752,12 @@ static bool stable_node_dup_remove_range(struct stable_node *stable_node,
 	return false;
 }
 
-static bool stable_node_chain_remove_range(struct stable_node *stable_node,
+static bool stable_node_chain_remove_range(struct ksm_stable_node *stable_node,
 					   unsigned long start_pfn,
 					   unsigned long end_pfn,
 					   struct rb_root *root)
 {
-	struct stable_node *dup;
+	struct ksm_stable_node *dup;
 	struct hlist_node *hlist_safe;
 
 	if (!is_stable_node_chain(stable_node)) {
@@ -2781,14 +2781,14 @@ static bool stable_node_chain_remove_range(struct stable_node *stable_node,
 static void ksm_check_stable_tree(unsigned long start_pfn,
 				  unsigned long end_pfn)
 {
-	struct stable_node *stable_node, *next;
+	struct ksm_stable_node *stable_node, *next;
 	struct rb_node *node;
 	int nid;
 
 	for (nid = 0; nid < ksm_nr_node_ids; nid++) {
 		node = rb_first(root_stable_tree + nid);
 		while (node) {
-			stable_node = rb_entry(node, struct stable_node, node);
+			stable_node = rb_entry(node, struct ksm_stable_node, node);
 			if (stable_node_chain_remove_range(stable_node,
 							   start_pfn, end_pfn,
 							   root_stable_tree +
-- 
2.20.1

[PATCH v2 5/7] ksm: convert ksm_mm_slot.mm_list to ksm_mm_slot.mm_node

[Qi Zheng]

In order to use common struct mm_slot, convert ksm_mm_slot.mm_list
to ksm_mm_slot.mm_node in advance, no functional change.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
 mm/ksm.c | 40 ++++++++++++++++++++--------------------
 1 file changed, 20 insertions(+), 20 deletions(-)

diff --git a/mm/ksm.c b/mm/ksm.c
index 3937111f9ab8..8c52aa7e0a02 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -114,13 +114,13 @@
 /**
  * struct ksm_mm_slot - ksm information per mm that is being scanned
  * @link: link to the mm_slots hash list
- * @mm_list: link into the mm_slots list, rooted in ksm_mm_head
+ * @mm_node: link into the mm_slots list, rooted in ksm_mm_head
  * @rmap_list: head for this mm_slot's singly-linked list of rmap_items
  * @mm: the mm that this information is valid for
  */
 struct ksm_mm_slot {
 	struct hlist_node link;
-	struct list_head mm_list;
+	struct list_head mm_node;
 	struct ksm_rmap_item *rmap_list;
 	struct mm_struct *mm;
 };
@@ -231,7 +231,7 @@ static LIST_HEAD(migrate_nodes);
 static DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS);
 
 static struct ksm_mm_slot ksm_mm_head = {
-	.mm_list = LIST_HEAD_INIT(ksm_mm_head.mm_list),
+	.mm_node = LIST_HEAD_INIT(ksm_mm_head.mm_node),
 };
 static struct ksm_scan ksm_scan = {
 	.mm_slot = &ksm_mm_head,
@@ -980,8 +980,8 @@ static int unmerge_and_remove_all_rmap_items(void)
 	int err = 0;
 
 	spin_lock(&ksm_mmlist_lock);
-	ksm_scan.mm_slot = list_entry(ksm_mm_head.mm_list.next,
-						struct ksm_mm_slot, mm_list);
+	ksm_scan.mm_slot = list_entry(ksm_mm_head.mm_node.next,
+						struct ksm_mm_slot, mm_node);
 	spin_unlock(&ksm_mmlist_lock);
 
 	for (mm_slot = ksm_scan.mm_slot; mm_slot != &ksm_mm_head;
@@ -1005,11 +1005,11 @@ static int unmerge_and_remove_all_rmap_items(void)
 		mmap_read_unlock(mm);
 
 		spin_lock(&ksm_mmlist_lock);
-		ksm_scan.mm_slot = list_entry(mm_slot->mm_list.next,
-						struct ksm_mm_slot, mm_list);
+		ksm_scan.mm_slot = list_entry(mm_slot->mm_node.next,
+						struct ksm_mm_slot, mm_node);
 		if (ksm_test_exit(mm)) {
 			hash_del(&mm_slot->link);
-			list_del(&mm_slot->mm_list);
+			list_del(&mm_slot->mm_node);
 			spin_unlock(&ksm_mmlist_lock);
 
 			free_mm_slot(mm_slot);
@@ -2250,7 +2250,7 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
 	struct vma_iterator vmi;
 	int nid;
 
-	if (list_empty(&ksm_mm_head.mm_list))
+	if (list_empty(&ksm_mm_head.mm_node))
 		return NULL;
 
 	slot = ksm_scan.mm_slot;
@@ -2291,7 +2291,7 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
 			root_unstable_tree[nid] = RB_ROOT;
 
 		spin_lock(&ksm_mmlist_lock);
-		slot = list_entry(slot->mm_list.next, struct ksm_mm_slot, mm_list);
+		slot = list_entry(slot->mm_node.next, struct ksm_mm_slot, mm_node);
 		ksm_scan.mm_slot = slot;
 		spin_unlock(&ksm_mmlist_lock);
 		/*
@@ -2364,8 +2364,8 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
 	remove_trailing_rmap_items(ksm_scan.rmap_list);
 
 	spin_lock(&ksm_mmlist_lock);
-	ksm_scan.mm_slot = list_entry(slot->mm_list.next,
-						struct ksm_mm_slot, mm_list);
+	ksm_scan.mm_slot = list_entry(slot->mm_node.next,
+						struct ksm_mm_slot, mm_node);
 	if (ksm_scan.address == 0) {
 		/*
 		 * We've completed a full scan of all vmas, holding mmap_lock
@@ -2377,7 +2377,7 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
 		 * mmap_lock then protects against race with MADV_MERGEABLE).
 		 */
 		hash_del(&slot->link);
-		list_del(&slot->mm_list);
+		list_del(&slot->mm_node);
 		spin_unlock(&ksm_mmlist_lock);
 
 		free_mm_slot(slot);
@@ -2426,7 +2426,7 @@ static void ksm_do_scan(unsigned int scan_npages)
 
 static int ksmd_should_run(void)
 {
-	return (ksm_run & KSM_RUN_MERGE) && !list_empty(&ksm_mm_head.mm_list);
+	return (ksm_run & KSM_RUN_MERGE) && !list_empty(&ksm_mm_head.mm_node);
 }
 
 static int ksm_scan_thread(void *nothing)
@@ -2523,7 +2523,7 @@ int __ksm_enter(struct mm_struct *mm)
 		return -ENOMEM;
 
 	/* Check ksm_run too?  Would need tighter locking */
-	needs_wakeup = list_empty(&ksm_mm_head.mm_list);
+	needs_wakeup = list_empty(&ksm_mm_head.mm_node);
 
 	spin_lock(&ksm_mmlist_lock);
 	insert_to_mm_slots_hash(mm, mm_slot);
@@ -2538,9 +2538,9 @@ int __ksm_enter(struct mm_struct *mm)
 	 * missed: then we might as well insert at the end of the list.
 	 */
 	if (ksm_run & KSM_RUN_UNMERGE)
-		list_add_tail(&mm_slot->mm_list, &ksm_mm_head.mm_list);
+		list_add_tail(&mm_slot->mm_node, &ksm_mm_head.mm_node);
 	else
-		list_add_tail(&mm_slot->mm_list, &ksm_scan.mm_slot->mm_list);
+		list_add_tail(&mm_slot->mm_node, &ksm_scan.mm_slot->mm_node);
 	spin_unlock(&ksm_mmlist_lock);
 
 	set_bit(MMF_VM_MERGEABLE, &mm->flags);
@@ -2571,11 +2571,11 @@ void __ksm_exit(struct mm_struct *mm)
 	if (mm_slot && ksm_scan.mm_slot != mm_slot) {
 		if (!mm_slot->rmap_list) {
 			hash_del(&mm_slot->link);
-			list_del(&mm_slot->mm_list);
+			list_del(&mm_slot->mm_node);
 			easy_to_free = 1;
 		} else {
-			list_move(&mm_slot->mm_list,
-				  &ksm_scan.mm_slot->mm_list);
+			list_move(&mm_slot->mm_node,
+				  &ksm_scan.mm_slot->mm_node);
 		}
 	}
 	spin_unlock(&ksm_mmlist_lock);
-- 
2.20.1

[PATCH v2 6/7] ksm: convert ksm_mm_slot.link to ksm_mm_slot.hash

[Qi Zheng]

In order to use common struct mm_slot, convert ksm_mm_slot.link
to ksm_mm_slot.hash in advance, no functional change.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
 mm/ksm.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/mm/ksm.c b/mm/ksm.c
index 8c52aa7e0a02..667efca75b0d 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -113,13 +113,13 @@
 
 /**
  * struct ksm_mm_slot - ksm information per mm that is being scanned
- * @link: link to the mm_slots hash list
+ * @hash: link to the mm_slots hash list
  * @mm_node: link into the mm_slots list, rooted in ksm_mm_head
  * @rmap_list: head for this mm_slot's singly-linked list of rmap_items
  * @mm: the mm that this information is valid for
  */
 struct ksm_mm_slot {
-	struct hlist_node link;
+	struct hlist_node hash;
 	struct list_head mm_node;
 	struct ksm_rmap_item *rmap_list;
 	struct mm_struct *mm;
@@ -424,7 +424,7 @@ static struct ksm_mm_slot *get_mm_slot(struct mm_struct *mm)
 {
 	struct ksm_mm_slot *slot;
 
-	hash_for_each_possible(mm_slots_hash, slot, link, (unsigned long)mm)
+	hash_for_each_possible(mm_slots_hash, slot, hash, (unsigned long)mm)
 		if (slot->mm == mm)
 			return slot;
 
@@ -435,7 +435,7 @@ static void insert_to_mm_slots_hash(struct mm_struct *mm,
 				    struct ksm_mm_slot *mm_slot)
 {
 	mm_slot->mm = mm;
-	hash_add(mm_slots_hash, &mm_slot->link, (unsigned long)mm);
+	hash_add(mm_slots_hash, &mm_slot->hash, (unsigned long)mm);
 }
 
 /*
@@ -1008,7 +1008,7 @@ static int unmerge_and_remove_all_rmap_items(void)
 		ksm_scan.mm_slot = list_entry(mm_slot->mm_node.next,
 						struct ksm_mm_slot, mm_node);
 		if (ksm_test_exit(mm)) {
-			hash_del(&mm_slot->link);
+			hash_del(&mm_slot->hash);
 			list_del(&mm_slot->mm_node);
 			spin_unlock(&ksm_mmlist_lock);
 
@@ -2376,7 +2376,7 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
 		 * or when all VM_MERGEABLE areas have been unmapped (and
 		 * mmap_lock then protects against race with MADV_MERGEABLE).
 		 */
-		hash_del(&slot->link);
+		hash_del(&slot->hash);
 		list_del(&slot->mm_node);
 		spin_unlock(&ksm_mmlist_lock);
 
@@ -2570,7 +2570,7 @@ void __ksm_exit(struct mm_struct *mm)
 	mm_slot = get_mm_slot(mm);
 	if (mm_slot && ksm_scan.mm_slot != mm_slot) {
 		if (!mm_slot->rmap_list) {
-			hash_del(&mm_slot->link);
+			hash_del(&mm_slot->hash);
 			list_del(&mm_slot->mm_node);
 			easy_to_free = 1;
 		} else {
-- 
2.20.1

[PATCH v2 7/7] ksm: convert to use common struct mm_slot

[Qi Zheng]

Convert to use common struct mm_slot, no functional change.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
 mm/ksm.c | 132 +++++++++++++++++++++++--------------------------------
 1 file changed, 56 insertions(+), 76 deletions(-)

diff --git a/mm/ksm.c b/mm/ksm.c
index 667efca75b0d..d8c4819d81eb 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -42,6 +42,7 @@
 
 #include <asm/tlbflush.h>
 #include "internal.h"
+#include "mm_slot.h"
 
 #ifdef CONFIG_NUMA
 #define NUMA(x)		(x)
@@ -113,16 +114,12 @@
 
 /**
  * struct ksm_mm_slot - ksm information per mm that is being scanned
- * @hash: link to the mm_slots hash list
- * @mm_node: link into the mm_slots list, rooted in ksm_mm_head
+ * @slot: hash lookup from mm to mm_slot
  * @rmap_list: head for this mm_slot's singly-linked list of rmap_items
- * @mm: the mm that this information is valid for
  */
 struct ksm_mm_slot {
-	struct hlist_node hash;
-	struct list_head mm_node;
+	struct mm_slot slot;
 	struct ksm_rmap_item *rmap_list;
-	struct mm_struct *mm;
 };
 
 /**
@@ -231,7 +228,7 @@ static LIST_HEAD(migrate_nodes);
 static DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS);
 
 static struct ksm_mm_slot ksm_mm_head = {
-	.mm_node = LIST_HEAD_INIT(ksm_mm_head.mm_node),
+	.slot.mm_node = LIST_HEAD_INIT(ksm_mm_head.slot.mm_node),
 };
 static struct ksm_scan ksm_scan = {
 	.mm_slot = &ksm_mm_head,
@@ -408,36 +405,6 @@ static inline void free_stable_node(struct ksm_stable_node *stable_node)
 	kmem_cache_free(stable_node_cache, stable_node);
 }
 
-static inline struct ksm_mm_slot *alloc_mm_slot(void)
-{
-	if (!mm_slot_cache)	/* initialization failed */
-		return NULL;
-	return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL);
-}
-
-static inline void free_mm_slot(struct ksm_mm_slot *mm_slot)
-{
-	kmem_cache_free(mm_slot_cache, mm_slot);
-}
-
-static struct ksm_mm_slot *get_mm_slot(struct mm_struct *mm)
-{
-	struct ksm_mm_slot *slot;
-
-	hash_for_each_possible(mm_slots_hash, slot, hash, (unsigned long)mm)
-		if (slot->mm == mm)
-			return slot;
-
-	return NULL;
-}
-
-static void insert_to_mm_slots_hash(struct mm_struct *mm,
-				    struct ksm_mm_slot *mm_slot)
-{
-	mm_slot->mm = mm;
-	hash_add(mm_slots_hash, &mm_slot->hash, (unsigned long)mm);
-}
-
 /*
  * ksmd, and unmerge_and_remove_all_rmap_items(), must not touch an mm's
  * page tables after it has passed through ksm_exit() - which, if necessary,
@@ -975,20 +942,22 @@ static int remove_all_stable_nodes(void)
 static int unmerge_and_remove_all_rmap_items(void)
 {
 	struct ksm_mm_slot *mm_slot;
+	struct mm_slot *slot;
 	struct mm_struct *mm;
 	struct vm_area_struct *vma;
 	int err = 0;
 
 	spin_lock(&ksm_mmlist_lock);
-	ksm_scan.mm_slot = list_entry(ksm_mm_head.mm_node.next,
-						struct ksm_mm_slot, mm_node);
+	slot = list_entry(ksm_mm_head.slot.mm_node.next,
+			  struct mm_slot, mm_node);
+	ksm_scan.mm_slot = mm_slot_entry(slot, struct ksm_mm_slot, slot);
 	spin_unlock(&ksm_mmlist_lock);
 
 	for (mm_slot = ksm_scan.mm_slot; mm_slot != &ksm_mm_head;
 	     mm_slot = ksm_scan.mm_slot) {
-		VMA_ITERATOR(vmi, mm_slot->mm, 0);
+		VMA_ITERATOR(vmi, mm_slot->slot.mm, 0);
 
-		mm = mm_slot->mm;
+		mm = mm_slot->slot.mm;
 		mmap_read_lock(mm);
 		for_each_vma(vmi, vma) {
 			if (ksm_test_exit(mm))
@@ -1005,14 +974,15 @@ static int unmerge_and_remove_all_rmap_items(void)
 		mmap_read_unlock(mm);
 
 		spin_lock(&ksm_mmlist_lock);
-		ksm_scan.mm_slot = list_entry(mm_slot->mm_node.next,
-						struct ksm_mm_slot, mm_node);
+		slot = list_entry(mm_slot->slot.mm_node.next,
+				  struct mm_slot, mm_node);
+		ksm_scan.mm_slot = mm_slot_entry(slot, struct ksm_mm_slot, slot);
 		if (ksm_test_exit(mm)) {
-			hash_del(&mm_slot->hash);
-			list_del(&mm_slot->mm_node);
+			hash_del(&mm_slot->slot.hash);
+			list_del(&mm_slot->slot.mm_node);
 			spin_unlock(&ksm_mmlist_lock);
 
-			free_mm_slot(mm_slot);
+			mm_slot_free(mm_slot_cache, mm_slot);
 			clear_bit(MMF_VM_MERGEABLE, &mm->flags);
 			mmdrop(mm);
 		} else
@@ -2233,7 +2203,7 @@ static struct ksm_rmap_item *get_next_rmap_item(struct ksm_mm_slot *mm_slot,
 	rmap_item = alloc_rmap_item();
 	if (rmap_item) {
 		/* It has already been zeroed */
-		rmap_item->mm = mm_slot->mm;
+		rmap_item->mm = mm_slot->slot.mm;
 		rmap_item->address = addr;
 		rmap_item->rmap_list = *rmap_list;
 		*rmap_list = rmap_item;
@@ -2244,17 +2214,18 @@ static struct ksm_rmap_item *get_next_rmap_item(struct ksm_mm_slot *mm_slot,
 static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
 {
 	struct mm_struct *mm;
-	struct ksm_mm_slot *slot;
+	struct ksm_mm_slot *mm_slot;
+	struct mm_slot *slot;
 	struct vm_area_struct *vma;
 	struct ksm_rmap_item *rmap_item;
 	struct vma_iterator vmi;
 	int nid;
 
-	if (list_empty(&ksm_mm_head.mm_node))
+	if (list_empty(&ksm_mm_head.slot.mm_node))
 		return NULL;
 
-	slot = ksm_scan.mm_slot;
-	if (slot == &ksm_mm_head) {
+	mm_slot = ksm_scan.mm_slot;
+	if (mm_slot == &ksm_mm_head) {
 		/*
 		 * A number of pages can hang around indefinitely on per-cpu
 		 * pagevecs, raised page count preventing write_protect_page
@@ -2291,20 +2262,23 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
 			root_unstable_tree[nid] = RB_ROOT;
 
 		spin_lock(&ksm_mmlist_lock);
-		slot = list_entry(slot->mm_node.next, struct ksm_mm_slot, mm_node);
-		ksm_scan.mm_slot = slot;
+		slot = list_entry(mm_slot->slot.mm_node.next,
+				  struct mm_slot, mm_node);
+		mm_slot = mm_slot_entry(slot, struct ksm_mm_slot, slot);
+		ksm_scan.mm_slot = mm_slot;
 		spin_unlock(&ksm_mmlist_lock);
 		/*
 		 * Although we tested list_empty() above, a racing __ksm_exit
 		 * of the last mm on the list may have removed it since then.
 		 */
-		if (slot == &ksm_mm_head)
+		if (mm_slot == &ksm_mm_head)
 			return NULL;
 next_mm:
 		ksm_scan.address = 0;
-		ksm_scan.rmap_list = &slot->rmap_list;
+		ksm_scan.rmap_list = &mm_slot->rmap_list;
 	}
 
+	slot = &mm_slot->slot;
 	mm = slot->mm;
 	vma_iter_init(&vmi, mm, ksm_scan.address);
 
@@ -2334,7 +2308,7 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
 			if (PageAnon(*page)) {
 				flush_anon_page(vma, *page, ksm_scan.address);
 				flush_dcache_page(*page);
-				rmap_item = get_next_rmap_item(slot,
+				rmap_item = get_next_rmap_item(mm_slot,
 					ksm_scan.rmap_list, ksm_scan.address);
 				if (rmap_item) {
 					ksm_scan.rmap_list =
@@ -2355,7 +2329,7 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
 	if (ksm_test_exit(mm)) {
 no_vmas:
 		ksm_scan.address = 0;
-		ksm_scan.rmap_list = &slot->rmap_list;
+		ksm_scan.rmap_list = &mm_slot->rmap_list;
 	}
 	/*
 	 * Nuke all the rmap_items that are above this current rmap:
@@ -2364,8 +2338,9 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
 	remove_trailing_rmap_items(ksm_scan.rmap_list);
 
 	spin_lock(&ksm_mmlist_lock);
-	ksm_scan.mm_slot = list_entry(slot->mm_node.next,
-						struct ksm_mm_slot, mm_node);
+	slot = list_entry(mm_slot->slot.mm_node.next,
+			  struct mm_slot, mm_node);
+	ksm_scan.mm_slot = mm_slot_entry(slot, struct ksm_mm_slot, slot);
 	if (ksm_scan.address == 0) {
 		/*
 		 * We've completed a full scan of all vmas, holding mmap_lock
@@ -2376,11 +2351,11 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
 		 * or when all VM_MERGEABLE areas have been unmapped (and
 		 * mmap_lock then protects against race with MADV_MERGEABLE).
 		 */
-		hash_del(&slot->hash);
-		list_del(&slot->mm_node);
+		hash_del(&mm_slot->slot.hash);
+		list_del(&mm_slot->slot.mm_node);
 		spin_unlock(&ksm_mmlist_lock);
 
-		free_mm_slot(slot);
+		mm_slot_free(mm_slot_cache, mm_slot);
 		clear_bit(MMF_VM_MERGEABLE, &mm->flags);
 		mmap_read_unlock(mm);
 		mmdrop(mm);
@@ -2397,8 +2372,8 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
 	}
 
 	/* Repeat until we've completed scanning the whole list */
-	slot = ksm_scan.mm_slot;
-	if (slot != &ksm_mm_head)
+	mm_slot = ksm_scan.mm_slot;
+	if (mm_slot != &ksm_mm_head)
 		goto next_mm;
 
 	ksm_scan.seqnr++;
@@ -2426,7 +2401,7 @@ static void ksm_do_scan(unsigned int scan_npages)
 
 static int ksmd_should_run(void)
 {
-	return (ksm_run & KSM_RUN_MERGE) && !list_empty(&ksm_mm_head.mm_node);
+	return (ksm_run & KSM_RUN_MERGE) && !list_empty(&ksm_mm_head.slot.mm_node);
 }
 
 static int ksm_scan_thread(void *nothing)
@@ -2516,17 +2491,20 @@ EXPORT_SYMBOL_GPL(ksm_madvise);
 int __ksm_enter(struct mm_struct *mm)
 {
 	struct ksm_mm_slot *mm_slot;
+	struct mm_slot *slot;
 	int needs_wakeup;
 
-	mm_slot = alloc_mm_slot();
+	mm_slot = mm_slot_alloc(mm_slot_cache);
 	if (!mm_slot)
 		return -ENOMEM;
 
+	slot = &mm_slot->slot;
+
 	/* Check ksm_run too?  Would need tighter locking */
-	needs_wakeup = list_empty(&ksm_mm_head.mm_node);
+	needs_wakeup = list_empty(&ksm_mm_head.slot.mm_node);
 
 	spin_lock(&ksm_mmlist_lock);
-	insert_to_mm_slots_hash(mm, mm_slot);
+	mm_slot_insert(mm_slots_hash, mm, slot);
 	/*
 	 * When KSM_RUN_MERGE (or KSM_RUN_STOP),
 	 * insert just behind the scanning cursor, to let the area settle
@@ -2538,9 +2516,9 @@ int __ksm_enter(struct mm_struct *mm)
 	 * missed: then we might as well insert at the end of the list.
 	 */
 	if (ksm_run & KSM_RUN_UNMERGE)
-		list_add_tail(&mm_slot->mm_node, &ksm_mm_head.mm_node);
+		list_add_tail(&slot->mm_node, &ksm_mm_head.slot.mm_node);
 	else
-		list_add_tail(&mm_slot->mm_node, &ksm_scan.mm_slot->mm_node);
+		list_add_tail(&slot->mm_node, &ksm_scan.mm_slot->slot.mm_node);
 	spin_unlock(&ksm_mmlist_lock);
 
 	set_bit(MMF_VM_MERGEABLE, &mm->flags);
@@ -2555,6 +2533,7 @@ int __ksm_enter(struct mm_struct *mm)
 void __ksm_exit(struct mm_struct *mm)
 {
 	struct ksm_mm_slot *mm_slot;
+	struct mm_slot *slot;
 	int easy_to_free = 0;
 
 	/*
@@ -2567,21 +2546,22 @@ void __ksm_exit(struct mm_struct *mm)
 	 */
 
 	spin_lock(&ksm_mmlist_lock);
-	mm_slot = get_mm_slot(mm);
+	slot = mm_slot_lookup(mm_slots_hash, mm);
+	mm_slot = mm_slot_entry(slot, struct ksm_mm_slot, slot);
 	if (mm_slot && ksm_scan.mm_slot != mm_slot) {
 		if (!mm_slot->rmap_list) {
-			hash_del(&mm_slot->hash);
-			list_del(&mm_slot->mm_node);
+			hash_del(&slot->hash);
+			list_del(&slot->mm_node);
 			easy_to_free = 1;
 		} else {
-			list_move(&mm_slot->mm_node,
-				  &ksm_scan.mm_slot->mm_node);
+			list_move(&slot->mm_node,
+				  &ksm_scan.mm_slot->slot.mm_node);
 		}
 	}
 	spin_unlock(&ksm_mmlist_lock);
 
 	if (easy_to_free) {
-		free_mm_slot(mm_slot);
+		mm_slot_free(mm_slot_cache, mm_slot);
 		clear_bit(MMF_VM_MERGEABLE, &mm->flags);
 		mmdrop(mm);
 	} else if (mm_slot) {
-- 
2.20.1

[PATCH mm-unstable] mm: thp: fix build error with CONFIG_SHMEM disabled

[Qi Zheng]

 From 9075ff5ab459b1b1df53e74261d24f300203ee9f Mon Sep 17 00:00:00 2001
From: Qi Zheng <zhengqi.arch@bytedance.com>
Date: Thu, 1 Sep 2022 07:26:25 +0000
Subject: [PATCH mm-unstable] mm: thp: fix build error with CONFIG_SHMEM
  disabled

Fix the following build error by changing function
parameter type from struct mm_sot * to struct khugepaged_mm_slot *:

mm/khugepaged.c: In function 'khugepaged_scan_mm_slot':
 >> mm/khugepaged.c:2056:45: error: passing argument 1 of 
'khugepaged_collapse_pte_mapped_thps' from incompatible pointer type 
[-Werror=incompatible-pointer-types]
     2056 |         khugepaged_collapse_pte_mapped_thps(mm_slot);
          |                                             ^~~~~~~
          |                                             |
          |                                             struct 
khugepaged_mm_slot *
    mm/khugepaged.c:2023:65: note: expected 'struct mm_slot *' but 
argument is of type 'struct khugepaged_mm_slot *'
     2023 | static void khugepaged_collapse_pte_mapped_thps(struct 
mm_slot *mm_slot)
          | 
~~~~~~~~~~~~~~~~^~~~~~~
    cc1: some warnings being treated as errors

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
  mm/khugepaged.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 2d74cf01f694..af3b07eb2389 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -2020,7 +2020,7 @@ static int khugepaged_scan_file(struct mm_struct 
*mm, struct file *file,
  	BUILD_BUG();
  }

-static void khugepaged_collapse_pte_mapped_thps(struct mm_slot *mm_slot)
+static void khugepaged_collapse_pte_mapped_thps(struct 
khugepaged_mm_slot *mm_slot)
  {
  }
  #endif
--
2.20.1


On 2022/8/31 11:19, Qi Zheng wrote:
> Rename private struct mm_slot to struct khugepaged_mm_slot and
> convert to use common struct mm_slot with no functional change.
> 
> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
> ---
>   mm/khugepaged.c | 121 ++++++++++++++++++++----------------------------
>   1 file changed, 51 insertions(+), 70 deletions(-)
> 
> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> index d8e388106322..2d74cf01f694 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -23,6 +23,7 @@
>   #include <asm/tlb.h>
>   #include <asm/pgalloc.h>
>   #include "internal.h"
> +#include "mm_slot.h"
>   
>   enum scan_result {
>   	SCAN_FAIL,
> @@ -104,17 +105,13 @@ struct collapse_control {
>   };
>   
>   /**
> - * struct mm_slot - hash lookup from mm to mm_slot
> - * @hash: hash collision list
> - * @mm_node: khugepaged scan list headed in khugepaged_scan.mm_head
> - * @mm: the mm that this information is valid for
> + * struct khugepaged_mm_slot - khugepaged information per mm that is being scanned
> + * @slot: hash lookup from mm to mm_slot
>    * @nr_pte_mapped_thp: number of pte mapped THP
>    * @pte_mapped_thp: address array corresponding pte mapped THP
>    */
> -struct mm_slot {
> -	struct hlist_node hash;
> -	struct list_head mm_node;
> -	struct mm_struct *mm;
> +struct khugepaged_mm_slot {
> +	struct mm_slot slot;
>   
>   	/* pte-mapped THP in this mm */
>   	int nr_pte_mapped_thp;
> @@ -131,7 +128,7 @@ struct mm_slot {
>    */
>   struct khugepaged_scan {
>   	struct list_head mm_head;
> -	struct mm_slot *mm_slot;
> +	struct khugepaged_mm_slot *mm_slot;
>   	unsigned long address;
>   };
>   
> @@ -395,8 +392,9 @@ int hugepage_madvise(struct vm_area_struct *vma,
>   int __init khugepaged_init(void)
>   {
>   	mm_slot_cache = kmem_cache_create("khugepaged_mm_slot",
> -					  sizeof(struct mm_slot),
> -					  __alignof__(struct mm_slot), 0, NULL);
> +					  sizeof(struct khugepaged_mm_slot),
> +					  __alignof__(struct khugepaged_mm_slot),
> +					  0, NULL);
>   	if (!mm_slot_cache)
>   		return -ENOMEM;
>   
> @@ -413,36 +411,6 @@ void __init khugepaged_destroy(void)
>   	kmem_cache_destroy(mm_slot_cache);
>   }
>   
> -static inline struct mm_slot *alloc_mm_slot(void)
> -{
> -	if (!mm_slot_cache)	/* initialization failed */
> -		return NULL;
> -	return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL);
> -}
> -
> -static inline void free_mm_slot(struct mm_slot *mm_slot)
> -{
> -	kmem_cache_free(mm_slot_cache, mm_slot);
> -}
> -
> -static struct mm_slot *get_mm_slot(struct mm_struct *mm)
> -{
> -	struct mm_slot *mm_slot;
> -
> -	hash_for_each_possible(mm_slots_hash, mm_slot, hash, (unsigned long)mm)
> -		if (mm == mm_slot->mm)
> -			return mm_slot;
> -
> -	return NULL;
> -}
> -
> -static void insert_to_mm_slots_hash(struct mm_struct *mm,
> -				    struct mm_slot *mm_slot)
> -{
> -	mm_slot->mm = mm;
> -	hash_add(mm_slots_hash, &mm_slot->hash, (long)mm);
> -}
> -
>   static inline int hpage_collapse_test_exit(struct mm_struct *mm)
>   {
>   	return atomic_read(&mm->mm_users) == 0;
> @@ -450,28 +418,31 @@ static inline int hpage_collapse_test_exit(struct mm_struct *mm)
>   
>   void __khugepaged_enter(struct mm_struct *mm)
>   {
> -	struct mm_slot *mm_slot;
> +	struct khugepaged_mm_slot *mm_slot;
> +	struct mm_slot *slot;
>   	int wakeup;
>   
> -	mm_slot = alloc_mm_slot();
> +	mm_slot = mm_slot_alloc(mm_slot_cache);
>   	if (!mm_slot)
>   		return;
>   
> +	slot = &mm_slot->slot;
> +
>   	/* __khugepaged_exit() must not run from under us */
>   	VM_BUG_ON_MM(hpage_collapse_test_exit(mm), mm);
>   	if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) {
> -		free_mm_slot(mm_slot);
> +		mm_slot_free(mm_slot_cache, mm_slot);
>   		return;
>   	}
>   
>   	spin_lock(&khugepaged_mm_lock);
> -	insert_to_mm_slots_hash(mm, mm_slot);
> +	mm_slot_insert(mm_slots_hash, mm, slot);
>   	/*
>   	 * Insert just behind the scanning cursor, to let the area settle
>   	 * down a little.
>   	 */
>   	wakeup = list_empty(&khugepaged_scan.mm_head);
> -	list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head);
> +	list_add_tail(&slot->mm_node, &khugepaged_scan.mm_head);
>   	spin_unlock(&khugepaged_mm_lock);
>   
>   	mmgrab(mm);
> @@ -491,21 +462,23 @@ void khugepaged_enter_vma(struct vm_area_struct *vma,
>   
>   void __khugepaged_exit(struct mm_struct *mm)
>   {
> -	struct mm_slot *mm_slot;
> +	struct khugepaged_mm_slot *mm_slot;
> +	struct mm_slot *slot;
>   	int free = 0;
>   
>   	spin_lock(&khugepaged_mm_lock);
> -	mm_slot = get_mm_slot(mm);
> +	slot = mm_slot_lookup(mm_slots_hash, mm);
> +	mm_slot = mm_slot_entry(slot, struct khugepaged_mm_slot, slot);
>   	if (mm_slot && khugepaged_scan.mm_slot != mm_slot) {
> -		hash_del(&mm_slot->hash);
> -		list_del(&mm_slot->mm_node);
> +		hash_del(&slot->hash);
> +		list_del(&slot->mm_node);
>   		free = 1;
>   	}
>   	spin_unlock(&khugepaged_mm_lock);
>   
>   	if (free) {
>   		clear_bit(MMF_VM_HUGEPAGE, &mm->flags);
> -		free_mm_slot(mm_slot);
> +		mm_slot_free(mm_slot_cache, mm_slot);
>   		mmdrop(mm);
>   	} else if (mm_slot) {
>   		/*
> @@ -1321,16 +1294,17 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm,
>   	return result;
>   }
>   
> -static void collect_mm_slot(struct mm_slot *mm_slot)
> +static void collect_mm_slot(struct khugepaged_mm_slot *mm_slot)
>   {
> -	struct mm_struct *mm = mm_slot->mm;
> +	struct mm_slot *slot = &mm_slot->slot;
> +	struct mm_struct *mm = slot->mm;
>   
>   	lockdep_assert_held(&khugepaged_mm_lock);
>   
>   	if (hpage_collapse_test_exit(mm)) {
>   		/* free mm_slot */
> -		hash_del(&mm_slot->hash);
> -		list_del(&mm_slot->mm_node);
> +		hash_del(&slot->hash);
> +		list_del(&slot->mm_node);
>   
>   		/*
>   		 * Not strictly needed because the mm exited already.
> @@ -1339,7 +1313,7 @@ static void collect_mm_slot(struct mm_slot *mm_slot)
>   		 */
>   
>   		/* khugepaged_mm_lock actually not necessary for the below */
> -		free_mm_slot(mm_slot);
> +		mm_slot_free(mm_slot_cache, mm_slot);
>   		mmdrop(mm);
>   	}
>   }
> @@ -1352,12 +1326,14 @@ static void collect_mm_slot(struct mm_slot *mm_slot)
>   static void khugepaged_add_pte_mapped_thp(struct mm_struct *mm,
>   					  unsigned long addr)
>   {
> -	struct mm_slot *mm_slot;
> +	struct khugepaged_mm_slot *mm_slot;
> +	struct mm_slot *slot;
>   
>   	VM_BUG_ON(addr & ~HPAGE_PMD_MASK);
>   
>   	spin_lock(&khugepaged_mm_lock);
> -	mm_slot = get_mm_slot(mm);
> +	slot = mm_slot_lookup(mm_slots_hash, mm);
> +	mm_slot = mm_slot_entry(slot, struct khugepaged_mm_slot, slot);
>   	if (likely(mm_slot && mm_slot->nr_pte_mapped_thp < MAX_PTE_MAPPED_THP))
>   		mm_slot->pte_mapped_thp[mm_slot->nr_pte_mapped_thp++] = addr;
>   	spin_unlock(&khugepaged_mm_lock);
> @@ -1489,9 +1465,10 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr)
>   	goto drop_hpage;
>   }
>   
> -static void khugepaged_collapse_pte_mapped_thps(struct mm_slot *mm_slot)
> +static void khugepaged_collapse_pte_mapped_thps(struct khugepaged_mm_slot *mm_slot)
>   {
> -	struct mm_struct *mm = mm_slot->mm;
> +	struct mm_slot *slot = &mm_slot->slot;
> +	struct mm_struct *mm = slot->mm;
>   	int i;
>   
>   	if (likely(mm_slot->nr_pte_mapped_thp == 0))
> @@ -2054,7 +2031,8 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
>   	__acquires(&khugepaged_mm_lock)
>   {
>   	struct vma_iterator vmi;
> -	struct mm_slot *mm_slot;
> +	struct khugepaged_mm_slot *mm_slot;
> +	struct mm_slot *slot;
>   	struct mm_struct *mm;
>   	struct vm_area_struct *vma;
>   	int progress = 0;
> @@ -2064,18 +2042,20 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
>   	lockdep_assert_held(&khugepaged_mm_lock);
>   	*result = SCAN_FAIL;
>   
> -	if (khugepaged_scan.mm_slot)
> +	if (khugepaged_scan.mm_slot) {
>   		mm_slot = khugepaged_scan.mm_slot;
> -	else {
> -		mm_slot = list_entry(khugepaged_scan.mm_head.next,
> +		slot = &mm_slot->slot;
> +	} else {
> +		slot = list_entry(khugepaged_scan.mm_head.next,
>   				     struct mm_slot, mm_node);
> +		mm_slot = mm_slot_entry(slot, struct khugepaged_mm_slot, slot);
>   		khugepaged_scan.address = 0;
>   		khugepaged_scan.mm_slot = mm_slot;
>   	}
>   	spin_unlock(&khugepaged_mm_lock);
>   	khugepaged_collapse_pte_mapped_thps(mm_slot);
>   
> -	mm = mm_slot->mm;
> +	mm = slot->mm;
>   	/*
>   	 * Don't wait for semaphore (to avoid long wait times).  Just move to
>   	 * the next mm on the list.
> @@ -2171,10 +2151,11 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
>   		 * khugepaged runs here, khugepaged_exit will find
>   		 * mm_slot not pointing to the exiting mm.
>   		 */
> -		if (mm_slot->mm_node.next != &khugepaged_scan.mm_head) {
> -			khugepaged_scan.mm_slot = list_entry(
> -				mm_slot->mm_node.next,
> -				struct mm_slot, mm_node);
> +		if (slot->mm_node.next != &khugepaged_scan.mm_head) {
> +			slot = list_entry(slot->mm_node.next,
> +					  struct mm_slot, mm_node);
> +			khugepaged_scan.mm_slot =
> +				mm_slot_entry(slot, struct khugepaged_mm_slot, slot);
>   			khugepaged_scan.address = 0;
>   		} else {
>   			khugepaged_scan.mm_slot = NULL;
> @@ -2269,7 +2250,7 @@ static void khugepaged_wait_work(void)
>   
>   static int khugepaged(void *none)
>   {
> -	struct mm_slot *mm_slot;
> +	struct khugepaged_mm_slot *mm_slot;
>   
>   	set_freezable();
>   	set_user_nice(current, MAX_NICE);

-- 
Thanks,
Qi