Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh...

[linux-2.6] / include / linux / mm.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index d4ab4e590e23753bdbd13cfa53ddf109491cc70f..a5c451816fdca003350570aa3139e2f32fbe45f9 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2,7 +2,6 @@
 #define _LINUX_MM_H
 
 #include <linux/errno.h>
-#include <linux/capability.h>
 
 #ifdef __KERNEL__
 
@@ -600,6 +599,7 @@ static inline struct address_space *page_mapping(struct page *page)
 {
        struct address_space *mapping = page->mapping;
 
+       VM_BUG_ON(PageSlab(page));
        if (unlikely(PageSwapCache(page)))
                mapping = &swapper_space;
 #ifdef CONFIG_SLUB
@@ -811,27 +811,31 @@ extern unsigned long do_mremap(unsigned long addr,
                               unsigned long flags, unsigned long new_addr);
 
 /*
- * Prototype to add a shrinker callback for ageable caches.
- * 
- * These functions are passed a count `nr_to_scan' and a gfpmask.  They should
- * scan `nr_to_scan' objects, attempting to free them.
+ * A callback you can register to apply pressure to ageable caches.
  *
- * The callback must return the number of objects which remain in the cache.
+ * 'shrink' is passed a count 'nr_to_scan' and a 'gfpmask'.  It should
+ * look through the least-recently-used 'nr_to_scan' entries and
+ * attempt to free them up.  It should return the number of objects
+ * which remain in the cache.  If it returns -1, it means it cannot do
+ * any scanning at this time (eg. there is a risk of deadlock).
  *
- * The callback will be passed nr_to_scan == 0 when the VM is querying the
- * cache size, so a fastpath for that case is appropriate.
- */
-typedef int (*shrinker_t)(int nr_to_scan, gfp_t gfp_mask);
-
-/*
- * Add an aging callback.  The int is the number of 'seeks' it takes
- * to recreate one of the objects that these functions age.
+ * The 'gfpmask' refers to the allocation we are currently trying to
+ * fulfil.
+ *
+ * Note that 'shrink' will be passed nr_to_scan == 0 when the VM is
+ * querying the cache size, so a fastpath for that case is appropriate.
  */
+struct shrinker {
+       int (*shrink)(int nr_to_scan, gfp_t gfp_mask);
+       int seeks;      /* seeks to recreate an obj */
 
-#define DEFAULT_SEEKS 2
-struct shrinker;
-extern struct shrinker *set_shrinker(int, shrinker_t);
-extern void remove_shrinker(struct shrinker *shrinker);
+       /* These are for internal use */
+       struct list_head list;
+       long nr;        /* objs pending delete */
+};
+#define DEFAULT_SEEKS 2 /* A good number if you don't know better. */
+extern void register_shrinker(struct shrinker *);
+extern void unregister_shrinker(struct shrinker *);
 
 /*
  * Some shared mappigns will want the pages marked read-only