mm/ksm.c: use new hashtable implementation

Switch ksm to use the new hashtable implementation.  This reduces the
amount of generic unrelated code in the ksm module.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 12 insertions, 18 deletions

diff --git a/mm/ksm.c b/mm/ksm.c
index e1f1f278075f..d3842b206f8a 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -33,7 +33,7 @@
 #include <linux/mmu_notifier.h>
 #include <linux/swap.h>
 #include <linux/ksm.h>
-#include <linux/hash.h>
+#include <linux/hashtable.h>
 #include <linux/freezer.h>
 #include <linux/oom.h>
 
@@ -156,9 +156,8 @@ struct rmap_item {
 static struct rb_root root_stable_tree = RB_ROOT;
 static struct rb_root root_unstable_tree = RB_ROOT;
 
-#define MM_SLOTS_HASH_SHIFT 10
-#define MM_SLOTS_HASH_HEADS (1 << MM_SLOTS_HASH_SHIFT)
-static struct hlist_head mm_slots_hash[MM_SLOTS_HASH_HEADS];
+#define MM_SLOTS_HASH_BITS 10
+static DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS);
 
 static struct mm_slot ksm_mm_head = {
         .mm_list = LIST_HEAD_INIT(ksm_mm_head.mm_list),
@@ -275,26 +274,21 @@ static inline void free_mm_slot(struct mm_slot *mm_slot)
 
 static struct mm_slot *get_mm_slot(struct mm_struct *mm)
 {
-        struct mm_slot *mm_slot;
-        struct hlist_head *bucket;
         struct hlist_node *node;
+        struct mm_slot *slot;
+
+        hash_for_each_possible(mm_slots_hash, slot, node, link, (unsigned long)mm)
+                if (slot->mm == mm)
+                        return slot;
 
-        bucket = &mm_slots_hash[hash_ptr(mm, MM_SLOTS_HASH_SHIFT)];
-        hlist_for_each_entry(mm_slot, node, bucket, link) {
-                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)
 {
-        struct hlist_head *bucket;
-
-        bucket = &mm_slots_hash[hash_ptr(mm, MM_SLOTS_HASH_SHIFT)];
         mm_slot->mm = mm;
-        hlist_add_head(&mm_slot->link, bucket);
+        hash_add(mm_slots_hash, &mm_slot->link, (unsigned long)mm);
 }
 
 static inline int in_stable_tree(struct rmap_item *rmap_item)
@@ -647,7 +641,7 @@ static int unmerge_and_remove_all_rmap_items(void)
                 ksm_scan.mm_slot = list_entry(mm_slot->mm_list.next,
                                                 struct mm_slot, mm_list);
                 if (ksm_test_exit(mm)) {
-                        hlist_del(&mm_slot->link);
+                        hash_del(&mm_slot->link);
                         list_del(&mm_slot->mm_list);
                         spin_unlock(&ksm_mmlist_lock);
 
@@ -1392,7 +1386,7 @@ next_mm:
                  * or when all VM_MERGEABLE areas have been unmapped (and
                  * mmap_sem then protects against race with MADV_MERGEABLE).
                  */
-                hlist_del(&slot->link);
+                hash_del(&slot->link);
                 list_del(&slot->mm_list);
                 spin_unlock(&ksm_mmlist_lock);
 
@@ -1559,7 +1553,7 @@ 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) {
-                        hlist_del(&mm_slot->link);
+                        hash_del(&mm_slot->link);
                         list_del(&mm_slot->mm_list);
                         easy_to_free = 1;
                 } else {