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Diffstat (limited to 'include/asm-um/mmu_context.h')
-rw-r--r--include/asm-um/mmu_context.h10
1 files changed, 9 insertions, 1 deletions
diff --git a/include/asm-um/mmu_context.h b/include/asm-um/mmu_context.h
index 095bb627b96..2edb4f1f789 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();
}