[PATCH] Decrease number of pointer derefs in exit.c
Decrease the number of pointer derefs in kernel/exit.c
Benefits of the patch:
- Fewer pointer dereferences should make the code slightly faster.
- Size of generated code is smaller
- improved readability
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/exit.c b/kernel/exit.c
index e75a51f..8027228 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1071,6 +1071,9 @@
}
if (likely(p->real_parent == p->parent) && likely(p->signal)) {
+ struct signal_struct *psig;
+ struct signal_struct *sig;
+
/*
* The resource counters for the group leader are in its
* own task_struct. Those for dead threads in the group
@@ -1087,24 +1090,26 @@
* here reaping other children at the same time.
*/
spin_lock_irq(&p->parent->sighand->siglock);
- p->parent->signal->cutime =
- cputime_add(p->parent->signal->cutime,
+ psig = p->parent->signal;
+ sig = p->signal;
+ psig->cutime =
+ cputime_add(psig->cutime,
cputime_add(p->utime,
- cputime_add(p->signal->utime,
- p->signal->cutime)));
- p->parent->signal->cstime =
- cputime_add(p->parent->signal->cstime,
+ cputime_add(sig->utime,
+ sig->cutime)));
+ psig->cstime =
+ cputime_add(psig->cstime,
cputime_add(p->stime,
- cputime_add(p->signal->stime,
- p->signal->cstime)));
- p->parent->signal->cmin_flt +=
- p->min_flt + p->signal->min_flt + p->signal->cmin_flt;
- p->parent->signal->cmaj_flt +=
- p->maj_flt + p->signal->maj_flt + p->signal->cmaj_flt;
- p->parent->signal->cnvcsw +=
- p->nvcsw + p->signal->nvcsw + p->signal->cnvcsw;
- p->parent->signal->cnivcsw +=
- p->nivcsw + p->signal->nivcsw + p->signal->cnivcsw;
+ cputime_add(sig->stime,
+ sig->cstime)));
+ psig->cmin_flt +=
+ p->min_flt + sig->min_flt + sig->cmin_flt;
+ psig->cmaj_flt +=
+ p->maj_flt + sig->maj_flt + sig->cmaj_flt;
+ psig->cnvcsw +=
+ p->nvcsw + sig->nvcsw + sig->cnvcsw;
+ psig->cnivcsw +=
+ p->nivcsw + sig->nivcsw + sig->cnivcsw;
spin_unlock_irq(&p->parent->sighand->siglock);
}