X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=include%2Fasm-um%2Fmmu_context.h;h=f709c784bf1296e21de0a33175e403e86a974df6;hb=af57d238aa2107e1b45d8dacad6e50db938f0567;hp=095bb627b96a1d52be4cc1291f48c308449f65a1;hpb=b857c730d4e960d1876ff56ce5c4bd81ea9ff5ae;p=linux-2.6

diff --git a/include/asm-um/mmu_context.h b/include/asm-um/mmu_context.h
index 095bb627b9..f709c784bf 100644
--- a/include/asm-um/mmu_context.h
+++ b/include/asm-um/mmu_context.h
@@ -7,7 +7,6 @@
 #define __UM_MMU_CONTEXT_H
 
 #include "linux/sched.h"
-#include "linux/config.h"
 #include "choose-mode.h"
 #include "um_mmu.h"
 
@@ -20,8 +19,17 @@ extern void force_flush_all(void);
 
 static inline void activate_mm(struct mm_struct *old, struct mm_struct *new)
 {
-	if (old != new)
-		force_flush_all();
+	/*
+	 * 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))
+		CHOOSE_MODE(force_flush_all(),
+			    switch_mm_skas(&new->context.skas.id));
 }
 
 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,