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Commit 3795e161 authored by Jesper Juhl's avatar Jesper Juhl Committed by Linus Torvalds
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[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: default avatarJesper Juhl <jesper.juhl@gmail.com>
Acked-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent a547dfe9

kernel/exit.c

+21 −16
Original line number Diff line number Diff line
@@ -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);

	}