DGL makes all decisions using pull_hp when preemption is enabled.

1 files changed, 21 insertions, 26 deletions

diff --git a/litmus/dgl.c b/litmus/dgl.c
index 40f298221839..1132b7ce92a9 100644
--- a/litmus/dgl.c
+++ b/litmus/dgl.c
@@ -67,7 +67,7 @@ static void print_waiting(struct dgl *dgl, struct dgl_resource *resource)
 /*
  * Add @req to @list in priority order (higher numbers are lower priority).
  */
-static void add_req(struct dgl_req *req, struct list_head *list)
+static void add_req(struct dgl *dgl, struct dgl_req *req, struct list_head *list)
 {
         struct dgl_req *pos;
         struct list_head *last = list;
@@ -82,7 +82,7 @@ static void add_req(struct dgl_req *req, struct list_head *list)
                 }
                 last = &pos->list;
 
-                BUG_ON(check++ > 10);
+                BUG_ON(check++ > dgl->num_replicas);
         }
         list_add(&req->list, last);
 }
@@ -92,16 +92,11 @@ static void release_cpu(struct dgl *dgl, struct dgl_group_req *greq)
         int cpu = greq->cpu;
         struct task_struct *task = greq->task;
 
-        TRACE_GREQ(greq, "no longer acquired on CPU %d\n", cpu);
+        TRACE_GREQ(greq, "No longer acquired on CPU %d\n", cpu);
         BUG_ON(dgl->acquired[cpu] != greq);
 
         dgl->acquired[cpu] = NULL;
         --dgl->running;
-
-        /* if (task) { */
-        /*      sched_trace_server_switch_away(cpu_sid(dgl, cpu), 0, */
-        /*                                     -task->pid, get_rt_job(task)); */
-        /* } */
 }
 
 static void take_cpu(struct dgl *dgl, struct dgl_group_req *greq)
@@ -114,11 +109,6 @@ static void take_cpu(struct dgl *dgl, struct dgl_group_req *greq)
 
         dgl->acquired[cpu] = greq;
         ++dgl->running;
-
-        /* if (task) { */
-        /*      sched_trace_server_switch_to(cpu_sid(dgl, cpu), 0, */
-        /*                                   -task->pid, get_rt_job(task)); */
-        /* } */
 }
 
 static int try_bump_lp(struct dgl *dgl, struct dgl_resource *resource,
@@ -176,7 +166,7 @@ static int try_bump_lp(struct dgl *dgl, struct dgl_resource *resource,
 
                 /* Now in waiting list */
                 list_del_init(&acquired->list);
-                add_req(acquired, &resource->waiting);
+                add_req(dgl, acquired, &resource->waiting);
 
                 BUG_ON(!acquired->satisfied);
                 acquired->satisfied = 0;
@@ -204,7 +194,7 @@ static int try_bump_lp(struct dgl *dgl, struct dgl_resource *resource,
 static unsigned long try_acquire(struct dgl *dgl, struct dgl_resource *resource,
                                  struct dgl_req *req)
 {
-        int word, bit, rid, room;
+        int word, bit, rid, room, bumped = 0;
         unsigned long waiting;
         struct dgl_group_req *greq;
 
@@ -214,9 +204,9 @@ static unsigned long try_acquire(struct dgl *dgl, struct dgl_resource *resource,
         TRACE_GREQ(greq, "try acquire\n");
 
         room = resource->free_replicas >= req->replicas;
-        if (!room) room = try_bump_lp(dgl, resource, req);
+        bumped = room || try_bump_lp(dgl, resource, req);
 
-        if (!room) {
+        if (!(room || bumped)) {
                 TRACE_GREQ(greq, "cannot acquire %d replicas, %d free\n",
                            req->replicas, resource->free_replicas);
                 return 0;
@@ -229,7 +219,7 @@ static unsigned long try_acquire(struct dgl *dgl, struct dgl_resource *resource,
         /* Move from waiting to acquired */
         req->satisfied = 1;
         list_del_init(&req->list);
-        add_req(req, &resource->acquired);
+        add_req(dgl, req, &resource->acquired);
 
         TRACE_GREQ(greq, "acquired %d replicas of rid %d\n",
                    req->replicas, rid);
@@ -253,6 +243,7 @@ static unsigned long try_acquire(struct dgl *dgl, struct dgl_resource *resource,
                 dgl->cpu_acquired(greq);
         }
 
+
         return 1;
 }
 
@@ -260,14 +251,12 @@ static void try_pull_hp(struct dgl *dgl, struct dgl_resource *resource)
 {
         int succ;
         struct dgl_req *waiting, *tmp;
+        struct list_head *wlist = &resource->waiting;
 
         TRACE("Pulling into resource\n");
 
-        list_for_each_entry_safe(waiting, tmp, &resource->waiting, list) {
-                if (!resource->free_replicas) {
-                        TRACE("Quitting with no more free replicas\n");
-                        break;
-                }
+        list_for_each_entry_safe(waiting, tmp, wlist, list) {
+                TRACE_GREQ(waiting->greq, "Trying to pull into resource\n");
                 succ = try_acquire(dgl, resource, waiting);
         }
 }
@@ -408,14 +397,20 @@ void add_group_req(struct dgl *dgl, struct dgl_group_req *greq, int cpu)
                                    req->list.prev, i, req->list.next);
                         list_del_init(&req->list);
                 }
-                BUG_ON(in_list(&req->list));
 
-                succ = try_acquire(dgl, resource, req);
+                add_req(dgl, req, &resource->waiting);
+
+                if (!dgl->cpu_preempted) {
+                        try_acquire(dgl, resource, req);
+                } else {
+                        try_pull_hp(dgl, resource);
+                }
+
+                succ = (dgl->acquired[greq->cpu] == greq);
                 all_succ &= succ;
 
                 if (!succ) {
                         TRACE_GREQ(greq, "waiting on rid %d\n", i);
-                        add_req(req, &resource->waiting);
                 }
         }