[PATCH] Decrease number of pointer derefs in exit.c

[PATCH] Decrease number of pointer derefs in exit.c

[Jesper Juhl]

Hi,

Here's a small patch to 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

Please consider applying.


Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
---

 kernel/exit.c |   37 +++++++++++++++++++++----------------
 1 files changed, 21 insertions(+), 16 deletions(-)

   text    data     bss     dec     hex filename
 11077       0       0   11077    2b45 exit.o.orig
 10997       0       0   10997    2af5 exit.o

--- linux-2.6.15-rc5-git1-orig/kernel/exit.c	2005-12-04 18:48:53.000000000 +0100
+++ linux-2.6.15-rc5-git1/kernel/exit.c	2005-12-06 22:11:17.000000000 +0100
@@ -1068,6 +1068,9 @@ static int wait_task_zombie(task_t *p, i
 	}
 
 	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
@@ -1084,24 +1087,26 @@ static int wait_task_zombie(task_t *p, i
 		 * 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);
 	}