Pull sn-features into release branch

[powerpc.git] / include / asm-um / mmu_context.h

diff --git a/include/asm-um/mmu_context.h b/include/asm-um/mmu_context.h
index 7529c9c..2edb4f1 100644 (file)
--- a/include/asm-um/mmu_context.h
+++ b/include/asm-um/mmu_context.h
@@ -16,8 +16,20 @@
 
 #define deactivate_mm(tsk,mm)  do { } while (0)
 
+extern void force_flush_all(void);
+
 static inline void activate_mm(struct mm_struct *old, struct mm_struct *new)
 {
+       /*
+        * This is called by fs/exec.c and fs/aio.c. In the first case, for an
+        * exec, we don't need to do anything as we're called from userspace
+        * and thus going to use a new host PID. In the second, we're called
+        * from a kernel thread, and thus need to go doing the mmap's on the
+        * host. Since they're very expensive, we want to avoid that as far as
+        * possible.
+        */
+       if (old != new && (current->flags & PF_BORROWED_MM))
+               force_flush_all();
 }
 
 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,