Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes...

[linux-2.6-omap-h63xx.git] / mm / mlock.c

diff --git a/mm/mlock.c b/mm/mlock.c
index 8b478350a2a1528487ea60113db54b5e6976a4cb..008ea70b7afa9a2baed56cdc9b6b43ef0b05a6ff 100644 (file)
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -60,6 +60,8 @@ void __clear_page_mlock(struct page *page)
                return;
        }
 
+       dec_zone_page_state(page, NR_MLOCK);
+       count_vm_event(UNEVICTABLE_PGCLEARED);
        if (!isolate_lru_page(page)) {
                putback_lru_page(page);
        } else {
@@ -69,6 +71,9 @@ void __clear_page_mlock(struct page *page)
                lru_add_drain_all();
                if (!isolate_lru_page(page))
                        putback_lru_page(page);
+               else if (PageUnevictable(page))
+                       count_vm_event(UNEVICTABLE_PGSTRANDED);
+
        }
 }
 
@@ -80,8 +85,12 @@ void mlock_vma_page(struct page *page)
 {
        BUG_ON(!PageLocked(page));
 
-       if (!TestSetPageMlocked(page) && !isolate_lru_page(page))
-               putback_lru_page(page);
+       if (!TestSetPageMlocked(page)) {
+               inc_zone_page_state(page, NR_MLOCK);
+               count_vm_event(UNEVICTABLE_PGMLOCKED);
+               if (!isolate_lru_page(page))
+                       putback_lru_page(page);
+       }
 }
 
 /*
@@ -106,9 +115,31 @@ static void munlock_vma_page(struct page *page)
 {
        BUG_ON(!PageLocked(page));
 
-       if (TestClearPageMlocked(page) && !isolate_lru_page(page)) {
-               try_to_munlock(page);
-               putback_lru_page(page);
+       if (TestClearPageMlocked(page)) {
+               dec_zone_page_state(page, NR_MLOCK);
+               if (!isolate_lru_page(page)) {
+                       int ret = try_to_munlock(page);
+                       /*
+                        * did try_to_unlock() succeed or punt?
+                        */
+                       if (ret == SWAP_SUCCESS || ret == SWAP_AGAIN)
+                               count_vm_event(UNEVICTABLE_PGMUNLOCKED);
+
+                       putback_lru_page(page);
+               } else {
+                       /*
+                        * We lost the race.  let try_to_unmap() deal
+                        * with it.  At least we get the page state and
+                        * mlock stats right.  However, page is still on
+                        * the noreclaim list.  We'll fix that up when
+                        * the page is eventually freed or we scan the
+                        * noreclaim list.
+                        */
+                       if (PageUnevictable(page))
+                               count_vm_event(UNEVICTABLE_PGSTRANDED);
+                       else
+                               count_vm_event(UNEVICTABLE_PGMUNLOCKED);
+               }
        }
 }
 
@@ -217,11 +248,24 @@ static long __mlock_vma_pages_range(struct vm_area_struct *vma,
                        addr += PAGE_SIZE;      /* for next get_user_pages() */
                        nr_pages--;
                }
+               ret = 0;
        }
 
        lru_add_drain_all();    /* to update stats */
 
-       return 0;       /* count entire vma as locked_vm */
+       return ret;     /* count entire vma as locked_vm */
+}
+
+/*
+ * convert get_user_pages() return value to posix mlock() error
+ */
+static int __mlock_posix_error_return(long retval)
+{
+       if (retval == -EFAULT)
+               retval = -ENOMEM;
+       else if (retval == -ENOMEM)
+               retval = -EAGAIN;
+       return retval;
 }
 
 #else /* CONFIG_UNEVICTABLE_LRU */
@@ -234,9 +278,15 @@ static long __mlock_vma_pages_range(struct vm_area_struct *vma,
                                   int mlock)
 {
        if (mlock && (vma->vm_flags & VM_LOCKED))
-               make_pages_present(start, end);
+               return make_pages_present(start, end);
+       return 0;
+}
+
+static inline int __mlock_posix_error_return(long retval)
+{
        return 0;
 }
+
 #endif /* CONFIG_UNEVICTABLE_LRU */
 
 /**
@@ -403,10 +453,7 @@ success:
                downgrade_write(&mm->mmap_sem);
 
                ret = __mlock_vma_pages_range(vma, start, end, 1);
-               if (ret > 0) {
-                       mm->locked_vm -= ret;
-                       ret = 0;
-               }
+
                /*
                 * Need to reacquire mmap sem in write mode, as our callers
                 * expect this.  We have no support for atomically upgrading
@@ -420,6 +467,11 @@ success:
                /* non-NULL *prev must contain @start, but need to check @end */
                if (!(*prev) || end > (*prev)->vm_end)
                        ret = -ENOMEM;
+               else if (ret > 0) {
+                       mm->locked_vm -= ret;
+                       ret = 0;
+               } else
+                       ret = __mlock_posix_error_return(ret); /* translate if needed */
        } else {
                /*
                 * TODO:  for unlocking, pages will already be resident, so