xnu-1228.9.59.tar.gz

[apple/xnu.git] / bsd / sys / mount_internal.h

diff --git a/bsd/sys/mount_internal.h b/bsd/sys/mount_internal.h
index 1ff74ca3ef26d251b60daa539154d24f89b0b8e0..eb59661724cc15d74a6c3d620dde59ca9ea6abd6 100644 (file)
--- a/bsd/sys/mount_internal.h
+++ b/bsd/sys/mount_internal.h
@@ -123,6 +123,7 @@ struct mount {
        lck_rw_t        mnt_rwlock;             /* mutex readwrite lock */
         lck_mtx_t      mnt_renamelock;         /* mutex that serializes renames that change shape of tree */
        vnode_t         mnt_devvp;              /* the device mounted on for local file systems */
+       uint32_t        mnt_devbsdunit;         /* the BSD unit number of the device */
        int32_t         mnt_crossref;           /* refernces to cover lookups  crossing into mp */
        int32_t         mnt_iterref;            /* refernces to cover iterations; drained makes it -ve  */
  
@@ -174,8 +175,6 @@ struct mount {
         */
        pid_t           mnt_dependent_pid;
        void            *mnt_dependent_process;
-
-       struct timeval  last_normal_IO_timestamp;
 };
 
 /*
@@ -340,6 +339,15 @@ struct user_statfs {
 #endif
 };
 
+/*
+ * throttle I/Os are affected only by normal I/Os happening on the same bsd device node.  For example, disk1s3 and
+ * disk1s5 are the same device node, while disk1s3 and disk2 are not (although disk2 might be a mounted disk image file
+ * and the disk image file resides on a partition in disk1).  The following constant defines the maximum number of
+ * different bsd device nodes the algorithm can consider, and larger numbers are rounded by this maximum.  Since
+ * throttled I/O is usually useful in non-server environment only, a small number 16 is enough in most cases
+ */
+#define LOWPRI_MAX_NUM_DEV 16
+
 __BEGIN_DECLS
 
 extern int mount_generation;
@@ -377,6 +385,11 @@ void mount_iterdrop(mount_t);
 void mount_iterdrain(mount_t);
 void mount_iterreset(mount_t);
 
+/* throttled I/O api */
+int throttle_get_io_policy(struct uthread **ut);
+extern void throttle_lowpri_io(boolean_t ok_to_sleep);
+int throttle_io_will_be_throttled(int lowpri_window_msecs, size_t devbsdunit);
+
 __END_DECLS
 
 #endif /* !_SYS_MOUNT_INTERNAL_H_ */