[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>

1 files changed, 21 insertions, 16 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index e75a51f33768..802722814925 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1071,6 +1071,9 @@ static int wait_task_zombie(task_t *p, int noreap,
         }
 
         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 @@ static int wait_task_zombie(task_t *p, int noreap,
                  * 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);
         }