X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=include%2Fasm-um%2Fmmu_context.h;h=2edb4f1f789cdb96e0208da409622db6f1eaa70b;hb=d67eb16f5d444fb6d173bcec889ddb2066c0fa0c;hp=095bb627b96a1d52be4cc1291f48c308449f65a1;hpb=99ad25a313bda566a346b46a6015afa65bc0a02b;p=powerpc.git

diff --git a/include/asm-um/mmu_context.h b/include/asm-um/mmu_context.h
index 095bb627b9..2edb4f1f78 100644
--- a/include/asm-um/mmu_context.h
+++ b/include/asm-um/mmu_context.h
@@ -20,7 +20,15 @@ extern void force_flush_all(void);
 
 static inline void activate_mm(struct mm_struct *old, struct mm_struct *new)
 {
-	if (old != 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();
 }