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v1.10: coll/libnbc: fix race condition with multi threaded apps #2443

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Merged
merged 2 commits into from
Dec 1, 2016
Merged

v1.10: coll/libnbc: fix race condition with multi threaded apps #2443

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1ebc19d
coll/libnbc: fix race condition with multi threaded apps
ggouaillardet Nov 21, 2016
ca12d2c
coll/libnbc: add some comments on how locks are used
ggouaillardet Nov 30, 2016
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5 changes: 4 additions & 1 deletion ompi/mca/coll/libnbc/coll_libnbc.h
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,8 @@
* Copyright (c) 2008 Cisco Systems, Inc. All rights reserved.
* Copyright (c) 2013 Los Alamos National Security, LLC. All rights
* reserved.
* Copyright (c) 2016 Research Organization for Information Science
* and Technology (RIST). All rights reserved.
* $COPYRIGHT$
*
* Additional copyrights may follow
Expand Down Expand Up @@ -70,7 +72,8 @@ struct ompi_coll_libnbc_component_t {
ompi_free_list_t requests;
opal_list_t active_requests;
int32_t active_comms;
opal_atomic_lock_t progress_lock;
opal_atomic_lock_t progress_lock; /* protect from recursive calls */
opal_mutex_t lock; /* protect access to the active_requests list */
};
typedef struct ompi_coll_libnbc_component_t ompi_coll_libnbc_component_t;

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11 changes: 11 additions & 0 deletions ompi/mca/coll/libnbc/coll_libnbc_component.c
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Original file line number Diff line number Diff line change
Expand Up @@ -89,6 +89,7 @@ libnbc_open(void)

OBJ_CONSTRUCT(&mca_coll_libnbc_component.requests, ompi_free_list_t);
OBJ_CONSTRUCT(&mca_coll_libnbc_component.active_requests, opal_list_t);
OBJ_CONSTRUCT(&mca_coll_libnbc_component.lock, opal_mutex_t);
ret = ompi_free_list_init(&mca_coll_libnbc_component.requests,
sizeof(ompi_coll_libnbc_request_t),
OBJ_CLASS(ompi_coll_libnbc_request_t),
Expand Down Expand Up @@ -116,6 +117,7 @@ libnbc_close(void)

OBJ_DESTRUCT(&mca_coll_libnbc_component.requests);
OBJ_DESTRUCT(&mca_coll_libnbc_component.active_requests);
OBJ_DESTRUCT(&mca_coll_libnbc_component.lock);

return OMPI_SUCCESS;
}
Expand Down Expand Up @@ -240,21 +242,30 @@ ompi_coll_libnbc_progress(void)
{
ompi_coll_libnbc_request_t* request, *next;

/* return if invoked recursively */
if (opal_atomic_trylock(&mca_coll_libnbc_component.progress_lock)) return 0;

/* process active requests, and use mca_coll_libnbc_component.lock to access the
* mca_coll_libnbc_component.active_requests list */
OPAL_THREAD_LOCK(&mca_coll_libnbc_component.lock);
OPAL_LIST_FOREACH_SAFE(request, next, &mca_coll_libnbc_component.active_requests,
ompi_coll_libnbc_request_t) {
OPAL_THREAD_UNLOCK(&mca_coll_libnbc_component.lock);
if (NBC_OK == NBC_Progress(request)) {
/* done, remove and complete */
OPAL_THREAD_LOCK(&mca_coll_libnbc_component.lock);
opal_list_remove_item(&mca_coll_libnbc_component.active_requests,
&request->super.super.super);
OPAL_THREAD_UNLOCK(&mca_coll_libnbc_component.lock);

request->super.req_status.MPI_ERROR = OMPI_SUCCESS;
OPAL_THREAD_LOCK(&ompi_request_lock);
ompi_request_complete(&request->super, true);
OPAL_THREAD_UNLOCK(&ompi_request_lock);
}
OPAL_THREAD_LOCK(&mca_coll_libnbc_component.lock);
}
OPAL_THREAD_UNLOCK(&mca_coll_libnbc_component.lock);

opal_atomic_unlock(&mca_coll_libnbc_component.progress_lock);

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2 changes: 2 additions & 0 deletions ompi/mca/coll/libnbc/nbc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -659,7 +659,9 @@ int NBC_Start(NBC_Handle *handle, NBC_Schedule *schedule) {
res = NBC_Start_round(handle);
if((NBC_OK != res)) { printf("Error in NBC_Start_round() (%i)\n", res); return res; }

OPAL_THREAD_LOCK(&mca_coll_libnbc_component.lock);
opal_list_append(&mca_coll_libnbc_component.active_requests, &(handle->super.super.super));
OPAL_THREAD_UNLOCK(&mca_coll_libnbc_component.lock);

return NBC_OK;
}
Expand Down