Linux 3.1 compat, super_block->s_shrink

[zfs.git] / module / zfs / zpl_super.c

diff --git a/module/zfs/zpl_super.c b/module/zfs/zpl_super.c
index 650e9c0..3abb26a 100644 (file)
--- a/module/zfs/zpl_super.c
+++ b/module/zfs/zpl_super.c
@@ -199,34 +199,120 @@ zpl_kill_sb(struct super_block *sb)
        kill_anon_super(sb);
 }
 
+#ifdef HAVE_SHRINK
+/*
+ * Linux 3.1 - 3.x API
+ *
+ * The Linux 3.1 API introduced per-sb cache shrinkers to replace the
+ * global ones.  This allows us a mechanism to cleanly target a specific
+ * zfs file system when the dnode and inode caches grow too large.
+ *
+ * In addition, the 3.0 kernel added the iterate_supers_type() helper
+ * function which is used to safely walk all of the zfs file systems.
+ */
+static void
+zpl_prune_sb(struct super_block *sb, void *arg)
+{
+       int objects = 0;
+       int error;
+
+       error = -zfs_sb_prune(sb, *(unsigned long *)arg, &objects);
+       ASSERT3S(error, <=, 0);
+
+       return;
+}
+
+void
+zpl_prune_sbs(int64_t bytes_to_scan, void *private)
+{
+       unsigned long nr_to_scan = (bytes_to_scan / sizeof(znode_t));
+
+       iterate_supers_type(&zpl_fs_type, zpl_prune_sb, &nr_to_scan);
+       kmem_reap();
+}
+#else
+/*
+ * Linux 2.6.x - 3.0 API
+ *
+ * These are best effort interfaces are provided by the SPL to induce
+ * the Linux VM subsystem to reclaim a fraction of the both dnode and
+ * inode caches.  Ideally, we want to just target the zfs file systems
+ * however our only option is to reclaim from them all.
+ */
+void
+zpl_prune_sbs(int64_t bytes_to_scan, void *private)
+{
+       unsigned long nr_to_scan = (bytes_to_scan / sizeof(znode_t));
+
+        shrink_dcache_memory(nr_to_scan, GFP_KERNEL);
+        shrink_icache_memory(nr_to_scan, GFP_KERNEL);
+        kmem_reap();
+}
+#endif /* HAVE_SHRINK */
+
+#ifdef HAVE_NR_CACHED_OBJECTS
+static int
+zpl_nr_cached_objects(struct super_block *sb)
+{
+       zfs_sb_t *zsb = sb->s_fs_info;
+       int nr;
+
+       mutex_enter(&zsb->z_znodes_lock);
+       nr = zsb->z_nr_znodes;
+       mutex_exit(&zsb->z_znodes_lock);
+
+       return (nr);
+}
+#endif /* HAVE_NR_CACHED_OBJECTS */
+
+#ifdef HAVE_FREE_CACHED_OBJECTS
+/*
+ * Attempt to evict some meta data from the cache.  The ARC operates in
+ * terms of bytes while the Linux VFS uses objects.  Now because this is
+ * just a best effort eviction and the exact values aren't critical so we
+ * extrapolate from an object count to a byte size using the znode_t size.
+ */
+static void
+zpl_free_cached_objects(struct super_block *sb, int nr_to_scan)
+{
+       arc_adjust_meta(nr_to_scan * sizeof(znode_t), B_FALSE);
+}
+#endif /* HAVE_FREE_CACHED_OBJECTS */
+
 const struct super_operations zpl_super_operations = {
-       .alloc_inode    = zpl_inode_alloc,
-       .destroy_inode  = zpl_inode_destroy,
-       .dirty_inode    = NULL,
-       .write_inode    = NULL,
-       .drop_inode     = NULL,
+       .alloc_inode            = zpl_inode_alloc,
+       .destroy_inode          = zpl_inode_destroy,
+       .dirty_inode            = NULL,
+       .write_inode            = NULL,
+       .drop_inode             = NULL,
 #ifdef HAVE_EVICT_INODE
-       .evict_inode    = zpl_evict_inode,
+       .evict_inode            = zpl_evict_inode,
 #else
-       .clear_inode    = zpl_clear_inode,
-       .delete_inode   = zpl_inode_delete,
+       .clear_inode            = zpl_clear_inode,
+       .delete_inode           = zpl_inode_delete,
 #endif /* HAVE_EVICT_INODE */
-       .put_super      = zpl_put_super,
-       .write_super    = NULL,
-       .sync_fs        = zpl_sync_fs,
-       .statfs         = zpl_statfs,
-       .remount_fs     = zpl_remount_fs,
-       .show_options   = zpl_show_options,
-       .show_stats     = NULL,
+       .put_super              = zpl_put_super,
+       .write_super            = NULL,
+       .sync_fs                = zpl_sync_fs,
+       .statfs                 = zpl_statfs,
+       .remount_fs             = zpl_remount_fs,
+       .show_options           = zpl_show_options,
+       .show_stats             = NULL,
+#ifdef HAVE_NR_CACHED_OBJECTS
+       .nr_cached_objects      = zpl_nr_cached_objects,
+#endif /* HAVE_NR_CACHED_OBJECTS */
+#ifdef HAVE_FREE_CACHED_OBJECTS
+       .free_cached_objects    = zpl_free_cached_objects,
+#endif /* HAVE_FREE_CACHED_OBJECTS */
 };
 
 struct file_system_type zpl_fs_type = {
-       .owner          = THIS_MODULE,
-       .name           = ZFS_DRIVER,
+       .owner                  = THIS_MODULE,
+       .name                   = ZFS_DRIVER,
 #ifdef HAVE_MOUNT_NODEV
-       .mount          = zpl_mount,
+       .mount                  = zpl_mount,
 #else
-       .get_sb         = zpl_get_sb,
+       .get_sb                 = zpl_get_sb,
 #endif /* HAVE_MOUNT_NODEV */
-       .kill_sb        = zpl_kill_sb,
+       .kill_sb                = zpl_kill_sb,
 };