cpumask: Partition_sched_domains takes array of cpumask_var_t

Currently partition_sched_domains() takes a 'struct cpumask
*doms_new' which is a kmalloc'ed array of cpumask_t.  You can't
have such an array if 'struct cpumask' is undefined, as we plan
for CONFIG_CPUMASK_OFFSTACK=y.

So, we make this an array of cpumask_var_t instead: this is the
same for the CONFIG_CPUMASK_OFFSTACK=n case, but requires
multiple allocations for the CONFIG_CPUMASK_OFFSTACK=y case.
Hence we add alloc_sched_domains() and free_sched_domains()
functions.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <200911031453.40668.rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 9 insertions, 10 deletions

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index d247381e7371..3cf2183b472d 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -537,8 +537,7 @@ update_domain_attr_tree(struct sched_domain_attr *dattr, struct cpuset *c)
  *      element of the partition (one sched domain) to be passed to
  *      partition_sched_domains().
  */
-/* FIXME: see the FIXME in partition_sched_domains() */
-static int generate_sched_domains(struct cpumask **domains,
+static int generate_sched_domains(cpumask_var_t **domains,
                         struct sched_domain_attr **attributes)
 {
         LIST_HEAD(q);           /* queue of cpusets to be scanned */
@@ -546,7 +545,7 @@ static int generate_sched_domains(struct cpumask **domains,
         struct cpuset **csa;    /* array of all cpuset ptrs */
         int csn;                /* how many cpuset ptrs in csa so far */
         int i, j, k;            /* indices for partition finding loops */
-        struct cpumask *doms;   /* resulting partition; i.e. sched domains */
+        cpumask_var_t *doms;    /* resulting partition; i.e. sched domains */
         struct sched_domain_attr *dattr;  /* attributes for custom domains */
         int ndoms = 0;          /* number of sched domains in result */
         int nslot;              /* next empty doms[] struct cpumask slot */
@@ -557,7 +556,8 @@ static int generate_sched_domains(struct cpumask **domains,
 
         /* Special case for the 99% of systems with one, full, sched domain */
         if (is_sched_load_balance(&top_cpuset)) {
-                doms = kmalloc(cpumask_size(), GFP_KERNEL);
+                ndoms = 1;
+                doms = alloc_sched_domains(ndoms);
                 if (!doms)
                         goto done;
 
@@ -566,9 +566,8 @@ static int generate_sched_domains(struct cpumask **domains,
                         *dattr = SD_ATTR_INIT;
                         update_domain_attr_tree(dattr, &top_cpuset);
                 }
-                cpumask_copy(doms, top_cpuset.cpus_allowed);
+                cpumask_copy(doms[0], top_cpuset.cpus_allowed);
 
-                ndoms = 1;
                 goto done;
         }
 
@@ -636,7 +635,7 @@ restart:
          * Now we know how many domains to create.
          * Convert <csn, csa> to <ndoms, doms> and populate cpu masks.
          */
-        doms = kmalloc(ndoms * cpumask_size(), GFP_KERNEL);
+        doms = alloc_sched_domains(ndoms);
         if (!doms)
                 goto done;
 
@@ -656,7 +655,7 @@ restart:
                         continue;
                 }
 
-                dp = doms + nslot;
+                dp = doms[nslot];
 
                 if (nslot == ndoms) {
                         static int warnings = 10;
@@ -718,7 +717,7 @@ done:
 static void do_rebuild_sched_domains(struct work_struct *unused)
 {
         struct sched_domain_attr *attr;
-        struct cpumask *doms;
+        cpumask_var_t *doms;
         int ndoms;
 
         get_online_cpus();
@@ -2052,7 +2051,7 @@ static int cpuset_track_online_cpus(struct notifier_block *unused_nb,
                                 unsigned long phase, void *unused_cpu)
 {
         struct sched_domain_attr *attr;
-        struct cpumask *doms;
+        cpumask_var_t *doms;
         int ndoms;
 
         switch (phase) {