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Commit b4028260 authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds
Browse files

ksm: rename kernel_pages_allocated 



We're not implementing swapping of KSM pages in its first release;
but when that follows, "kernel_pages_allocated" will be a very poor
name for the sysfs file showing number of nodes in the stable tree:
rename that to "pages_shared" throughout.

But we already have a "pages_shared", counting those page slots
sharing the shared pages: first rename that to... "pages_sharing".

What will become of "max_kernel_pages" when the pages shared can
be swapped?  I guess it will just be removed, so keep that name.

Signed-off-by: default avatarHugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: default avatarIzik Eidus <ieidus@redhat.com>
Acked-by: default avatarAndrea 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 339aa624

mm/ksm.c

+28 −29
Original line number Diff line number Diff line
@@ -150,10 +150,10 @@ static struct kmem_cache *rmap_item_cache; 
static struct kmem_cache *mm_slot_cache;



/* The number of nodes in the stable tree */

static unsigned long ksm_kernel_pages_allocated;

static unsigned long ksm_pages_shared;



/* The number of page slots sharing those nodes */

static unsigned long ksm_pages_shared;

static unsigned long ksm_pages_sharing;



/* Limit on the number of unswappable pages used */

static unsigned long ksm_max_kernel_pages;
@@ -384,7 +384,7 @@ static void remove_rmap_item_from_tree(struct rmap_item *rmap_item) 
				next_item->address |= NODE_FLAG;

			} else {

				rb_erase(&rmap_item->node, &root_stable_tree);

				ksm_kernel_pages_allocated--;

				ksm_pages_shared--;

			}

		} else {

			struct rmap_item *prev_item = rmap_item->prev;
@@ -398,7 +398,7 @@ static void remove_rmap_item_from_tree(struct rmap_item *rmap_item) 
		}



		rmap_item->next = NULL;

		ksm_pages_shared--;

		ksm_pages_sharing--;



	} else if (rmap_item->address & NODE_FLAG) {

		unsigned char age;
@@ -748,7 +748,7 @@ static int try_to_merge_two_pages(struct mm_struct *mm1, unsigned long addr1, 
	 * is the number of kernel pages that we hold.

	 */

	if (ksm_max_kernel_pages &&

	    ksm_max_kernel_pages <= ksm_kernel_pages_allocated)

	    ksm_max_kernel_pages <= ksm_pages_shared)

		return err;



	kpage = alloc_page(GFP_HIGHUSER);
@@ -787,7 +787,7 @@ static int try_to_merge_two_pages(struct mm_struct *mm1, unsigned long addr1, 
		if (err)

			break_cow(mm1, addr1);

		else

			ksm_pages_shared += 2;

			ksm_pages_sharing += 2;

	}



	put_page(kpage);
@@ -817,7 +817,7 @@ static int try_to_merge_with_ksm_page(struct mm_struct *mm1, 
	up_read(&mm1->mmap_sem);



	if (!err)

		ksm_pages_shared++;

		ksm_pages_sharing++;



	return err;

}
@@ -928,7 +928,7 @@ static struct rmap_item *stable_tree_insert(struct page *page, 
		}

	}



	ksm_kernel_pages_allocated++;

	ksm_pages_shared++;



	rmap_item->address |= NODE_FLAG | STABLE_FLAG;

	rmap_item->next = NULL;
@@ -1044,7 +1044,7 @@ static void cmp_and_merge_page(struct page *page, struct rmap_item *rmap_item) 
	tree_rmap_item = stable_tree_search(page, page2, rmap_item);

	if (tree_rmap_item) {

		if (page == page2[0]) {			/* forked */

			ksm_pages_shared++;

			ksm_pages_sharing++;

			err = 0;

		} else

			err = try_to_merge_with_ksm_page(rmap_item->mm,
@@ -1107,7 +1107,7 @@ static void cmp_and_merge_page(struct page *page, struct rmap_item *rmap_item) 
				break_cow(tree_rmap_item->mm,

						tree_rmap_item->address);

				break_cow(rmap_item->mm, rmap_item->address);

				ksm_pages_shared -= 2;

				ksm_pages_sharing -= 2;

			}

		}
@@ -1423,7 +1423,7 @@ static ssize_t run_store(struct kobject *kobj, struct kobj_attribute *attr, 
	/*

	 * KSM_RUN_MERGE sets ksmd running, and 0 stops it running.

	 * KSM_RUN_UNMERGE stops it running and unmerges all rmap_items,

	 * breaking COW to free the kernel_pages_allocated (but leaves

	 * breaking COW to free the unswappable pages_shared (but leaves

	 * mm_slots on the list for when ksmd may be set running again).

	 */
@@ -1442,22 +1442,6 @@ static ssize_t run_store(struct kobject *kobj, struct kobj_attribute *attr, 
}

KSM_ATTR(run);



static ssize_t pages_shared_show(struct kobject *kobj,

				 struct kobj_attribute *attr, char *buf)

{

	return sprintf(buf, "%lu\n",

			ksm_pages_shared - ksm_kernel_pages_allocated);

}

KSM_ATTR_RO(pages_shared);



static ssize_t kernel_pages_allocated_show(struct kobject *kobj,

					   struct kobj_attribute *attr,

					   char *buf)

{

	return sprintf(buf, "%lu\n", ksm_kernel_pages_allocated);

}

KSM_ATTR_RO(kernel_pages_allocated);



static ssize_t max_kernel_pages_store(struct kobject *kobj,

				      struct kobj_attribute *attr,

				      const char *buf, size_t count)
@@ -1481,13 +1465,28 @@ static ssize_t max_kernel_pages_show(struct kobject *kobj, 
}

KSM_ATTR(max_kernel_pages);



static ssize_t pages_shared_show(struct kobject *kobj,

				 struct kobj_attribute *attr, char *buf)

{

	return sprintf(buf, "%lu\n", ksm_pages_shared);

}

KSM_ATTR_RO(pages_shared);



static ssize_t pages_sharing_show(struct kobject *kobj,

				  struct kobj_attribute *attr, char *buf)

{

	return sprintf(buf, "%lu\n",

			ksm_pages_sharing - ksm_pages_shared);

}

KSM_ATTR_RO(pages_sharing);



static struct attribute *ksm_attrs[] = {

	&sleep_millisecs_attr.attr,

	&pages_to_scan_attr.attr,

	&run_attr.attr,

	&pages_shared_attr.attr,

	&kernel_pages_allocated_attr.attr,

	&max_kernel_pages_attr.attr,

	&pages_shared_attr.attr,

	&pages_sharing_attr.attr,

	NULL,

};