[PATCH resend] ksm: cleanup for mm_slots_hash

Prev: quick lookup memcg by ID
Next: [PATCH]drivers/usb/host/ehci-sched.c Fix typo

From: Lai Jiangshan on 2 Aug 2010 23:30

---

Andrea Arcangeli <aarcange(a)redhat.com> wrote:
>
> I just talked with Izik and he agrees with patch! ;)

Avi Kivity <avi(a)redhat.com> wrote:
> Note, to get the patch merged your best bet is to copy linux-mm and
> Andrew Morton.

Subject: [PATCH resend] ksm: cleanup for mm_slots_hash

Use compile-allocated memory instead of dynamic allocated
memory for mm_slots_hash.

Use hash_ptr() instead divisions for bucket calculation.

Signed-off-by: Lai Jiangshan <laijs(a)cn.fujitsu.com>
Signed-off-by: Izik Eidus <ieidus(a)redhat.com>
---
diff --git a/mm/ksm.c b/mm/ksm.c
index 6c3e99b..f69ff28 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -33,6 +33,7 @@
#include <linux/mmu_notifier.h>
#include <linux/swap.h>
#include <linux/ksm.h>
+#include <linux/hash.h>

#include <asm/tlbflush.h>
#include "internal.h"
@@ -153,8 +154,9 @@ 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_HEADS 1024
-static struct hlist_head *mm_slots_hash;
+#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];

static struct mm_slot ksm_mm_head = {
.mm_list = LIST_HEAD_INIT(ksm_mm_head.mm_list),
@@ -269,28 +271,13 @@ static inline void free_mm_slot(struct mm_slot *mm_slot)
kmem_cache_free(mm_slot_cache, mm_slot);
}

-static int __init mm_slots_hash_init(void)
-{
- mm_slots_hash = kzalloc(MM_SLOTS_HASH_HEADS * sizeof(struct hlist_head),
- GFP_KERNEL);
- if (!mm_slots_hash)
- return -ENOMEM;
- return 0;
-}
-
-static void __init mm_slots_hash_free(void)
-{
- kfree(mm_slots_hash);
-}
-
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[((unsigned long)mm / sizeof(struct mm_struct))
- % MM_SLOTS_HASH_HEADS];
+ 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;
@@ -303,8 +290,7 @@ static void insert_to_mm_slots_hash(struct mm_struct *mm,
{
struct hlist_head *bucket;

- bucket = &mm_slots_hash[((unsigned long)mm / sizeof(struct mm_struct))
- % MM_SLOTS_HASH_HEADS];
+ bucket = &mm_slots_hash[hash_ptr(mm, MM_SLOTS_HASH_SHIFT)];
mm_slot->mm = mm;
hlist_add_head(&mm_slot->link, bucket);
}
@@ -1943,15 +1929,11 @@ static int __init ksm_init(void)
if (err)
goto out;

- err = mm_slots_hash_init();
- if (err)
- goto out_free1;
-
ksm_thread = kthread_run(ksm_scan_thread, NULL, "ksmd");
if (IS_ERR(ksm_thread)) {
printk(KERN_ERR "ksm: creating kthread failed\n");
err = PTR_ERR(ksm_thread);
- goto out_free2;
+ goto out_free;
}

#ifdef CONFIG_SYSFS
@@ -1959,7 +1941,7 @@ static int __init ksm_init(void)
if (err) {
printk(KERN_ERR "ksm: register sysfs failed\n");
kthread_stop(ksm_thread);
- goto out_free2;
+ goto out_free;
}
#else
ksm_run = KSM_RUN_MERGE; /* no way for user to start it */
@@ -1975,9 +1957,7 @@ static int __init ksm_init(void)
#endif
return 0;

-out_free2:
- mm_slots_hash_free();
-out_free1:
+out_free:
ksm_slab_free();
out:
return err;
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo(a)vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

 | 
Pages: 1
Prev: quick lookup memcg by ID
Next: [PATCH]drivers/usb/host/ehci-sched.c Fix typo