[POWERPC] spusched: fix cpu/node binding

Add a cpus_allowed allowed filed to struct spu_context so that we always
use the cpu mask of the owning thread instead of the one happening to
call into the scheduler.  Also use this information in
grab_runnable_context to avoid spurious wakeups.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

diff --git a/arch/powerpc/platforms/cell/spufs/context.c b/arch/powerpc/platforms/cell/spufs/context.c
index c778d9178e0f1fce1c7af60f9257d5034c31266a..6ff2a75589f3d439838bd27521476bcdcb1389c5 100644 (file)
--- a/arch/powerpc/platforms/cell/spufs/context.c
+++ b/arch/powerpc/platforms/cell/spufs/context.c
@@ -53,7 +53,7 @@ struct spu_context *alloc_spu_context(struct spu_gang *gang)
        INIT_LIST_HEAD(&ctx->rq);
        if (gang)
                spu_gang_add_ctx(gang, ctx);
-
+       ctx->cpus_allowed = current->cpus_allowed;
        spu_set_timeslice(ctx);
        goto out;
 out_free:

diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c
index 3707c7fdbdeef5127696e4c5ff8276648bdbd7ee..69272620a6b75e3a46fe644e472009b2cc8c7140 100644 (file)
--- a/arch/powerpc/platforms/cell/spufs/sched.c
+++ b/arch/powerpc/platforms/cell/spufs/sched.c
@@ -112,6 +112,16 @@ void __spu_update_sched_info(struct spu_context *ctx)
        else
                ctx->prio = current->static_prio;
        ctx->policy = current->policy;
+
+       /*
+        * A lot of places that don't hold active_mutex poke into
+        * cpus_allowed, including grab_runnable_context which
+        * already holds the runq_lock.  So abuse runq_lock
+        * to protect this field aswell.
+        */
+       spin_lock(&spu_prio->runq_lock);
+       ctx->cpus_allowed = current->cpus_allowed;
+       spin_unlock(&spu_prio->runq_lock);
 }
 
 void spu_update_sched_info(struct spu_context *ctx)
@@ -123,16 +133,27 @@ void spu_update_sched_info(struct spu_context *ctx)
        mutex_unlock(&spu_prio->active_mutex[node]);
 }
 
-static inline int node_allowed(int node)
+static int __node_allowed(struct spu_context *ctx, int node)
 {
-       cpumask_t mask;
+       if (nr_cpus_node(node)) {
+               cpumask_t mask = node_to_cpumask(node);
 
-       if (!nr_cpus_node(node))
-               return 0;
-       mask = node_to_cpumask(node);
-       if (!cpus_intersects(mask, current->cpus_allowed))
-               return 0;
-       return 1;
+               if (cpus_intersects(mask, ctx->cpus_allowed))
+                       return 1;
+       }
+
+       return 0;
+}
+
+static int node_allowed(struct spu_context *ctx, int node)
+{
+       int rval;
+
+       spin_lock(&spu_prio->runq_lock);
+       rval = __node_allowed(ctx, node);
+       spin_unlock(&spu_prio->runq_lock);
+
+       return rval;
 }
 
 /**
@@ -289,7 +310,7 @@ static struct spu *spu_get_idle(struct spu_context *ctx)
 
        for (n = 0; n < MAX_NUMNODES; n++, node++) {
                node = (node < MAX_NUMNODES) ? node : 0;
-               if (!node_allowed(node))
+               if (!node_allowed(ctx, node))
                        continue;
                spu = spu_alloc_node(node);
                if (spu)
@@ -321,7 +342,7 @@ static struct spu *find_victim(struct spu_context *ctx)
        node = cpu_to_node(raw_smp_processor_id());
        for (n = 0; n < MAX_NUMNODES; n++, node++) {
                node = (node < MAX_NUMNODES) ? node : 0;
-               if (!node_allowed(node))
+               if (!node_allowed(ctx, node))
                        continue;
 
                mutex_lock(&spu_prio->active_mutex[node]);
@@ -416,23 +437,28 @@ int spu_activate(struct spu_context *ctx, unsigned long flags)
  * Remove the highest priority context on the runqueue and return it
  * to the caller.  Returns %NULL if no runnable context was found.
  */
-static struct spu_context *grab_runnable_context(int prio)
+static struct spu_context *grab_runnable_context(int prio, int node)
 {
-       struct spu_context *ctx = NULL;
+       struct spu_context *ctx;
        int best;
 
        spin_lock(&spu_prio->runq_lock);
        best = sched_find_first_bit(spu_prio->bitmap);
-       if (best < prio) {
+       while (best < prio) {
                struct list_head *rq = &spu_prio->runq[best];
 
-               BUG_ON(list_empty(rq));
-
-               ctx = list_entry(rq->next, struct spu_context, rq);
-               __spu_del_from_rq(ctx);
+               list_for_each_entry(ctx, rq, rq) {
+                       /* XXX(hch): check for affinity here aswell */
+                       if (__node_allowed(ctx, node)) {
+                               __spu_del_from_rq(ctx);
+                               goto found;
+                       }
+               }
+               best++;
        }
+       ctx = NULL;
+ found:
        spin_unlock(&spu_prio->runq_lock);
-
        return ctx;
 }
 
@@ -442,7 +468,7 @@ static int __spu_deactivate(struct spu_context *ctx, int force, int max_prio)
        struct spu_context *new = NULL;
 
        if (spu) {
-               new = grab_runnable_context(max_prio);
+               new = grab_runnable_context(max_prio, spu->node);
                if (new || force) {
                        spu_remove_from_active_list(spu);
                        spu_unbind_context(spu, ctx);
@@ -496,9 +522,11 @@ static void spusched_tick(struct spu_context *ctx)
         * tick and try again.
         */
        if (mutex_trylock(&ctx->state_mutex)) {
-               struct spu_context *new = grab_runnable_context(ctx->prio + 1);
+               struct spu *spu = ctx->spu;
+               struct spu_context *new;
+
+               new = grab_runnable_context(ctx->prio + 1, spu->node);
                if (new) {
-                       struct spu *spu = ctx->spu;
 
                        __spu_remove_from_active_list(spu);
                        spu_unbind_context(spu, ctx);

diff --git a/arch/powerpc/platforms/cell/spufs/spufs.h b/arch/powerpc/platforms/cell/spufs/spufs.h
index ff77f904fa3163bdd634068eec839c94e6c46f33..98d3c18b2b6fc391c6c0ddd68bac2a1ac750a170 100644 (file)
--- a/arch/powerpc/platforms/cell/spufs/spufs.h
+++ b/arch/powerpc/platforms/cell/spufs/spufs.h
@@ -26,6 +26,7 @@
 #include <linux/mutex.h>
 #include <linux/spinlock.h>
 #include <linux/fs.h>
+#include <linux/cpumask.h>
 
 #include <asm/spu.h>
 #include <asm/spu_csa.h>
@@ -80,6 +81,7 @@ struct spu_context {
        struct list_head rq;
        unsigned int time_slice;
        unsigned long sched_flags;
+       cpumask_t cpus_allowed;
        int policy;
        int prio;
 };