[RFC v2 3/7] mm,ksm: use new hashtable implementation

Sasha Levin
2012-08-03T14:23:04Z

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>
---
mm/ksm.c | 29 +++++++++--------------------
1 files changed, 9 insertions(+), 20 deletions(-)

diff --git a/mm/ksm.c b/mm/ksm.c
index 47c8853..72d062a 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>

@@ -157,8 +157,8 @@ 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_hash_cmp(slot, key) ((slot)->mm == (key))
+DEFINE_STATIC_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_SHIFT);

static struct mm_slot ksm_mm_head = {
.mm_list = LIST_HEAD_INIT(ksm_mm_head.mm_list),
@@ -275,26 +275,15 @@ 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;
-
- 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;
+ return hash_get(&mm_slots_hash, mm, struct mm_slot,
+ link, mm_hash_cmp);
}

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, (long)mm);
}

static inline int in_stable_tree(struct rmap_item *rmap_item)
@@ -647,7 +636,7 @@ 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);

@@ -1385,7 +1374,7 @@ 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);

@@ -1548,7 +1537,7 @@ 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 {
--
1.7.8.6