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: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Izik Eidus <ieidus@redhat.com>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/ksm.c b/mm/ksm.c
index cf072c54df3297dbe956921a92d27a82543cbd86..46b4c522ea4fe79c159bdfb034d5f527392d077d 100644 (file)
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -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,
 };