Fix for a bug Galen noticed yesterday -- make the shared memory only

be allocated the first time a sm coll is selected for a communicator,
not before.

This commit was SVN r7647.

ompi/mca/coll/sm/coll_sm.h

@@ -37,7 +37,7 @@
 #define D(foo)
 #endif
 
-#if 0
+#if OMPI_ENABLE_DEBUG
 #include <sched.h>
 #define SPIN sched_yield()
 #else
@@ -190,6 +190,21 @@ extern "C" {
             the division once and then just use the value without
             having to re-calculate. */
         int sm_segs_per_inuse_flag;
+
+        /** Whether the component's shared memory has been [lazily]
+            initialized or not */
+        bool sm_component_setup;
+
+        /** Once the component has been lazily initialized, keep the
+            state of it around */
+        bool sm_component_setup_success;
+
+        /** A lock protecting the lazy initialzation of the component
+            (SINCE THERE IS NO STATIC INITIALIZER FOR
+            opal_atomic_lock_t, THIS *MUST* BE THE LAST MEMBER OF THE
+            STRUCT!) */
+        opal_atomic_lock_t sm_component_setup_lock;
+
     };
     /**
      * Convenience typedef

ompi/mca/coll/sm/coll_sm_component.c

@@ -133,7 +133,11 @@ mca_coll_sm_component_t mca_coll_sm_component = {
     0, /* mpool data size -- filled in below */
     NULL, /* data mpool pointer */
     false, /* whether this process created the data mpool */
-    NULL /* pointer to meta data about bootstrap area */
+    NULL, /* pointer to meta data about bootstrap area */
+    false, /* whether the component sm has been [lazily] inited or not */
+    false /* whether lazy init was successful or not */
+    /* the lock for lazy initialization is not initialized here --
+       there is no static initializer for opal_atomic_lock_t */
 };
 
 

ompi/mca/coll/sm/coll_sm_module.c

@@ -110,7 +110,6 @@ static const mca_coll_base_module_1_0_0_t module = {
 int mca_coll_sm_init_query(bool enable_progress_threads,
                            bool enable_mpi_threads)
 {
-    int ret;
 #if 0
     /* JMS: Arrgh.  Unfortunately, we don't have this information by
        the time this is invoked -- the GPR compound command doesn't
@@ -132,29 +131,12 @@ int mca_coll_sm_init_query(bool enable_progress_threads,
     free(procs);
 #endif
 
-    /* Ok, we have local peers.  So setup the bootstrap file */
+    /* Don't do much here because we don't really want to allocate any
+       shared memory until this component is selected to be used. */
 
-    if (OMPI_SUCCESS != (ret = bootstrap_init())) {
+    mca_coll_sm_component.sm_data_mpool_created = false;
-        return ret;
+    mca_coll_sm_component.sm_component_setup = false;
-    }
+    opal_atomic_init(&mca_coll_sm_component.sm_component_setup_lock, 0);
-
-    /* Can we get an mpool allocation?  See if there was one created
-       already.  If not, try to make one. */
-
-    mca_coll_sm_component.sm_data_mpool = 
-        mca_mpool_base_module_lookup(mca_coll_sm_component.sm_mpool_name);
-    if (NULL == mca_coll_sm_component.sm_data_mpool) {
-        mca_coll_sm_component.sm_data_mpool = 
-            mca_mpool_base_module_create(mca_coll_sm_component.sm_mpool_name,
-                                         NULL, NULL);
-        if (NULL == mca_coll_sm_component.sm_data_mpool) {
-            mca_coll_sm_bootstrap_finalize();
-            return OMPI_ERR_OUT_OF_RESOURCE;
-        }
-        mca_coll_sm_component.sm_data_mpool_created = true;
-    } else {
-        mca_coll_sm_component.sm_data_mpool_created = false;
-    }
 
     /* Alles gut */
 
@@ -171,6 +153,13 @@ const mca_coll_base_module_1_0_0_t *
 mca_coll_sm_comm_query(struct ompi_communicator_t *comm, int *priority,
                        struct mca_coll_base_comm_t **data)
 {
+    /* See if someone has previously lazily initialized and failed */
+
+    if (mca_coll_sm_component.sm_component_setup &&
+        !mca_coll_sm_component.sm_component_setup_success) {
+        return NULL;
+    }
+    
     /* If we're intercomm, or if there's only one process in the
        communicator, or if not all the processes in the communicator
        are not on this node, then we don't want to run */
@@ -227,6 +216,51 @@ sm_module_init(struct ompi_communicator_t *comm)
     char *base;
     const int num_barrier_buffers = 2;
 
+    /* Once-per-component setup.  This may happen at any time --
+       during MPI_INIT or later.  So we must protect this with locks
+       to ensure that only one thread in the process actually does
+       this setup. */
+
+    opal_atomic_lock(&mca_coll_sm_component.sm_component_setup_lock);
+    if (!mca_coll_sm_component.sm_component_setup) {
+        mca_coll_sm_component.sm_component_setup = true;
+
+        if (OMPI_SUCCESS != bootstrap_init()) {
+            mca_coll_sm_component.sm_component_setup_success = false;
+            opal_atomic_unlock(&mca_coll_sm_component.sm_component_setup_lock);
+            return NULL;
+        }
+
+        /* Can we get an mpool allocation?  See if there was one created
+           already.  If not, try to make one. */
+        
+        mca_coll_sm_component.sm_data_mpool = 
+            mca_mpool_base_module_lookup(mca_coll_sm_component.sm_mpool_name);
+        if (NULL == mca_coll_sm_component.sm_data_mpool) {
+            mca_coll_sm_component.sm_data_mpool = 
+                mca_mpool_base_module_create(mca_coll_sm_component.sm_mpool_name,
+                                             NULL, NULL);
+            if (NULL == mca_coll_sm_component.sm_data_mpool) {
+                mca_coll_sm_bootstrap_finalize();
+                mca_coll_sm_component.sm_component_setup_success = false;
+                opal_atomic_unlock(&mca_coll_sm_component.sm_component_setup_lock);
+                return NULL;
+            }
+            mca_coll_sm_component.sm_data_mpool_created = true;
+        } else {
+            mca_coll_sm_component.sm_data_mpool_created = false;
+        }
+        mca_coll_sm_component.sm_component_setup_success = true;
+    }
+    opal_atomic_unlock(&mca_coll_sm_component.sm_component_setup_lock);
+
+    /* Double check to see if some interleaved lazy init failed before
+       we got in here */
+
+    if (!mca_coll_sm_component.sm_component_setup_success) {
+        return NULL;
+    }
+
     /* Get some space to setup memory affinity (just easier to try to
        alloc here to handle the error case) */
 
@@ -727,8 +761,9 @@ static int bootstrap_comm(ompi_communicator_t *comm)
 
 /*
  * This function is not static and has a prefix-rule-enabled name
- * because it gets called from the component.  This is only called
+ * because it gets called from the component (but may also be called
- * once -- no need for reference counting or thread protection.
+ * from above).  This is only called once -- no need for reference
+ * counting or thread protection.
  */
 int mca_coll_sm_bootstrap_finalize(void)
 {