[PATCH] Cpuset: remove useless sched domain line

[PATCH] Cpuset: remove useless sched domain line

[Paul Jackson]

From: Paul Jackson <pj@sgi.com>

Remove a useless line from the sched domain setup code in cpusets.

When I removed the 'is_removed()' flag test from the sched domain
setup code in cpusets, as part of my July 23, 2006 patch:

    Cpuset: fix ABBA deadlock with cpu hotplug lock

I failed to notice that this opened the door to a little bit of code
simplification.  A line of code that had to cover for the possibility
that a cpuset marked cpu_exclusive was marked for removal could
be eliminated.  In the code section visible in this patch, it is
now the case that cur->cpus_allowed is always a subset of pspan,
so it is always a no-op to cpus_or() cur->cpus_allowed into pspan.

Signed-off-by: Paul Jackson <pj@sgi.com>

---

 kernel/cpuset.c |    1 -
 1 files changed, 1 deletion(-)

--- 2.6.19-rc1-mm1.orig/kernel/cpuset.c	2006-10-13 21:31:16.000000000 -0700
+++ 2.6.19-rc1-mm1/kernel/cpuset.c	2006-10-13 21:32:20.000000000 -0700
@@ -783,7 +783,6 @@ static void update_cpu_domains(struct cp
 			cpus_andnot(pspan, pspan, c->cpus_allowed);
 	}
 	if (!is_cpu_exclusive(cur)) {
-		cpus_or(pspan, pspan, cur->cpus_allowed);
 		if (cpus_equal(pspan, cur->cpus_allowed))
 			return;
 		cspan = CPU_MASK_NONE;

-- 
                  I won't rest till it's the best ...
                  Programmer, Linux Scalability
                  Paul Jackson <pj@sgi.com> 1.925.600.0401

[PATCH] Cpuset: remove useless sched domain line

[Paul Jackson]

From: Paul Jackson <pj@sgi.com>

Remove a useless line from the sched domain setup code in cpusets.

When I removed the 'is_removed()' flag test from the sched domain
setup code in cpusets, as part of my July 23, 2006 patch:

    Cpuset: fix ABBA deadlock with cpu hotplug lock

I failed to notice that this opened the door to a little bit of code
simplification.  A line of code that had to cover for the possibility
that a cpuset marked cpu_exclusive was marked for removal could
be eliminated.  In the code section visible in this patch, it is
now the case that cur->cpus_allowed is always a subset of pspan,
so it is always a no-op to cpus_or() cur->cpus_allowed into pspan.

Signed-off-by: Paul Jackson <pj@sgi.com>

---

Resending what I just sent an hour ago - this time with akpm
on the "To" list, like I meant to the first time.

I believe this is ready for *-mm.

	-pj

 kernel/cpuset.c |    1 -
 1 files changed, 1 deletion(-)

--- 2.6.19-rc1-mm1.orig/kernel/cpuset.c	2006-10-13 21:31:16.000000000 -0700
+++ 2.6.19-rc1-mm1/kernel/cpuset.c	2006-10-13 21:32:20.000000000 -0700
@@ -783,7 +783,6 @@ static void update_cpu_domains(struct cp
 			cpus_andnot(pspan, pspan, c->cpus_allowed);
 	}
 	if (!is_cpu_exclusive(cur)) {
-		cpus_or(pspan, pspan, cur->cpus_allowed);
 		if (cpus_equal(pspan, cur->cpus_allowed))
 			return;
 		cspan = CPU_MASK_NONE;

-- 
                  I won't rest till it's the best ...
                  Programmer, Linux Scalability
                  Paul Jackson <pj@sgi.com> 1.925.600.0401