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Commit d9f8984c authored by Lai Jiangshan's avatar Lai Jiangshan Committed by Linus Torvalds
Browse files

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: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: default avatarIzik Eidus <ieidus@redhat.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e31f3698

mm/ksm.c

+9 −29
Original line number Diff line number Diff line
@@ -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);

}
@@ -1938,15 +1924,11 @@ 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
@@ -1954,7 +1936,7 @@ 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 */
@@ -1970,9 +1952,7 @@ 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;