X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=include%2Fasm-um%2Fmmu_context.h;h=2edb4f1f789cdb96e0208da409622db6f1eaa70b;hb=d67eb16f5d444fb6d173bcec889ddb2066c0fa0c;hp=7529c9c853dda226c1e42749121ed74b4b3e958e;hpb=4cda1fd78781c31e2a3d9dd87ee05d39cb76b3f9;p=powerpc.git

diff --git a/include/asm-um/mmu_context.h b/include/asm-um/mmu_context.h
index 7529c9c853..2edb4f1f78 100644
--- 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,