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oshmem: fix race condition on new contexts #7065

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merged 1 commit into from
Nov 30, 2019
Merged

oshmem: fix race condition on new contexts #7065

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59 changes: 38 additions & 21 deletions oshmem/mca/spml/ucx/spml_ucx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -573,19 +573,17 @@ static inline void _ctx_add(mca_spml_ucx_ctx_array_t *array, mca_spml_ucx_ctx_t
array->ctxs_count++;
}

static inline void _ctx_remove(mca_spml_ucx_ctx_array_t *array, mca_spml_ucx_ctx_t *ctx)
static inline void _ctx_remove(mca_spml_ucx_ctx_array_t *array, mca_spml_ucx_ctx_t *ctx, int i)
{
int i;

for (i = 0; i < array->ctxs_count; i++) {
for (; i < array->ctxs_count; i++) {
if (array->ctxs[i] == ctx) {
array->ctxs[i] = array->ctxs[array->ctxs_count-1];
array->ctxs[array->ctxs_count-1] = NULL;
array->ctxs_count--;
break;
}
}

array->ctxs_count--;
opal_atomic_wmb ();
}

Expand Down Expand Up @@ -681,27 +679,45 @@ static int mca_spml_ucx_ctx_create_common(long options, mca_spml_ucx_ctx_t **ucx

int mca_spml_ucx_ctx_create(long options, shmem_ctx_t *ctx)
{
mca_spml_ucx_ctx_t *ucx_ctx;
int rc;
mca_spml_ucx_ctx_t *ucx_ctx = NULL;
mca_spml_ucx_ctx_array_t *idle_array = &mca_spml_ucx.idle_array;
mca_spml_ucx_ctx_array_t *active_array = &mca_spml_ucx.active_array;
int i = 0, rc = OSHMEM_SUCCESS;

/* Take a lock controlling context creation. AUX context may set specific
* UCX parameters affecting worker creation, which are not needed for
* regular contexts. */
pthread_mutex_lock(&mca_spml_ucx.ctx_create_mutex);
rc = mca_spml_ucx_ctx_create_common(options, &ucx_ctx);
pthread_mutex_unlock(&mca_spml_ucx.ctx_create_mutex);
if (rc != OSHMEM_SUCCESS) {
return rc;
}

if (mca_spml_ucx.active_array.ctxs_count == 0) {
opal_progress_register(spml_ucx_ctx_progress);
}

/* Check if we have an idle context to reuse */
SHMEM_MUTEX_LOCK(mca_spml_ucx.internal_mutex);
_ctx_add(&mca_spml_ucx.active_array, ucx_ctx);
for (i = 0; i < idle_array->ctxs_count; i++) {
if (idle_array->ctxs[i]->options & options) {
ucx_ctx = idle_array->ctxs[i];
_ctx_remove(idle_array, ucx_ctx, i);
break;
}
}
SHMEM_MUTEX_UNLOCK(mca_spml_ucx.internal_mutex);

/* If we cannot reuse, create new ctx */
if (ucx_ctx == NULL) {
pthread_mutex_lock(&mca_spml_ucx.ctx_create_mutex);
rc = mca_spml_ucx_ctx_create_common(options, &ucx_ctx);
pthread_mutex_unlock(&mca_spml_ucx.ctx_create_mutex);
if (rc != OSHMEM_SUCCESS) {
return rc;
}
}

if (!(options & SHMEM_CTX_PRIVATE)) {
SHMEM_MUTEX_LOCK(mca_spml_ucx.internal_mutex);
_ctx_add(&mca_spml_ucx.active_array, ucx_ctx);
if (mca_spml_ucx.active_array.ctxs_count == 0) {
opal_progress_register(spml_ucx_ctx_progress);
}
SHMEM_MUTEX_UNLOCK(mca_spml_ucx.internal_mutex);
}

(*ctx) = (shmem_ctx_t)ucx_ctx;
return OSHMEM_SUCCESS;
}
Expand All @@ -711,13 +727,14 @@ void mca_spml_ucx_ctx_destroy(shmem_ctx_t ctx)
MCA_SPML_CALL(quiet(ctx));

SHMEM_MUTEX_LOCK(mca_spml_ucx.internal_mutex);
_ctx_remove(&mca_spml_ucx.active_array, (mca_spml_ucx_ctx_t *)ctx);
if (!(((mca_spml_ucx_ctx_t *)ctx)->options & SHMEM_CTX_PRIVATE)) {
_ctx_remove(&mca_spml_ucx.active_array, (mca_spml_ucx_ctx_t *)ctx, 0);
}
_ctx_add(&mca_spml_ucx.idle_array, (mca_spml_ucx_ctx_t *)ctx);
SHMEM_MUTEX_UNLOCK(mca_spml_ucx.internal_mutex);

if (!mca_spml_ucx.active_array.ctxs_count) {
opal_progress_unregister(spml_ucx_ctx_progress);
}
SHMEM_MUTEX_UNLOCK(mca_spml_ucx.internal_mutex);
}

int mca_spml_ucx_get(shmem_ctx_t ctx, void *src_addr, size_t size, void *dst_addr, int src)
Expand Down