diff options
Diffstat (limited to 'include/asm-um/mmu_context.h')
| -rw-r--r-- | include/asm-um/mmu_context.h | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/include/asm-um/mmu_context.h b/include/asm-um/mmu_context.h index 095bb62..2edb4f1 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(); } |