[Xen-devel] [PATCH 5/8] gnttab: re-arrange struct active_grant_entry

["Jan Beulich" <JBeulich@xxxxxxxx>]

While benign to 32-bit arches, this shrinks the size from 56 to 48
bytes on 64-bit ones (while still leaving a 16-bit hole).

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/common/grant_table.c
+++ b/xen/common/grant_table.c
@@ -160,15 +160,15 @@ shared_entry_header(struct grant_table *
 struct active_grant_entry {
     uint32_t      pin;    /* Reference count information.             */
     domid_t       domid;  /* Domain being granted access.             */
-    struct domain *trans_domain;
+    unsigned int  start:15; /* For sub-page grants, the start offset
+                               in the page.                           */
+    bool          is_sub_page:1; /* True if this is a sub-page grant. */
+    unsigned int  length:16; /* For sub-page grants, the length of the
+                                grant.                                */
     grant_ref_t   trans_gref;
+    struct domain *trans_domain;
     unsigned long frame;  /* Frame being granted.                     */
     unsigned long gfn;    /* Guest's idea of the frame being granted. */
-    unsigned      is_sub_page:1; /* True if this is a sub-page grant. */
-    unsigned      start:15; /* For sub-page grants, the start offset
-                               in the page.                           */
-    unsigned      length:16; /* For sub-page grants, the length of the
-                                grant.                                */
     spinlock_t    lock;      /* lock to protect access of this entry.
                                 see docs/misc/grant-tables.txt for
                                 locking protocol                      */




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