mempool: Introduce rseq_mempool_attr_set_max_nr_ranges

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I5417673d16ce7cfa5e8f2b9c120978f8633664bc

3 files changed, 28 insertions, 4 deletions

diff --git a/include/rseq/mempool.h b/include/rseq/mempool.h
index 4555a01..0b552df 100644
--- a/include/rseq/mempool.h
+++ b/include/rseq/mempool.h
@@ -466,6 +466,17 @@ int rseq_mempool_attr_set_percpu(struct rseq_mempool_attr *attr,
 int rseq_mempool_attr_set_global(struct rseq_mempool_attr *attr, size_t stride);
 
 /*
+ * rseq_mempool_attr_set_max_nr_ranges: Set upper-limit to range allocation.
+ *
+ * Set an upper-limit to range allocation. A @max_nr_ranges value of
+ * 0 means no limit (default).
+ *
+ * Returns 0 on success, -1 with errno=EINVAL if arguments are invalid.
+ */
+int rseq_mempool_attr_set_max_nr_ranges(struct rseq_mempool_attr *attr,
+		unsigned long max_nr_ranges);
+
+/*
  * rseq_mempool_range_init_numa: NUMA initialization helper for memory range.
  *
  * Helper which can be used from mempool_attr @init_func to move a CPU
diff --git a/src/rseq-mempool.c b/src/rseq-mempool.c
index 1bcfc8c..bf569a6 100644
--- a/src/rseq-mempool.c
+++ b/src/rseq-mempool.c
@@ -52,9 +52,6 @@
 
 #define RANGE_HEADER_OFFSET	sizeof(struct rseq_mempool_range)
 
-//TODO: make this configurable
-#define MEMPOOL_MAX_NR_RANGES	1
-
 struct free_list_node;
 
 struct free_list_node {
@@ -81,6 +78,8 @@ struct rseq_mempool_attr {
 	enum mempool_type type;
 	size_t stride;
 	int max_nr_cpus;
+
+	unsigned long max_nr_ranges;
 };
 
 struct rseq_mempool_range;
@@ -446,7 +445,8 @@ struct rseq_mempool_range *rseq_mempool_range_create(struct rseq_mempool *pool)
 	void *header;
 	void *base;
 
-	if (pool->nr_ranges >= MEMPOOL_MAX_NR_RANGES) {
+	if (pool->attr.max_nr_ranges &&
+			pool->nr_ranges >= pool->attr.max_nr_ranges) {
 		errno = ENOMEM;
 		return NULL;
 	}
@@ -908,6 +908,17 @@ int rseq_mempool_attr_set_global(struct rseq_mempool_attr *attr,
 	return 0;
 }
 
+int rseq_mempool_attr_set_max_nr_ranges(struct rseq_mempool_attr *attr,
+		unsigned long max_nr_ranges)
+{
+	if (!attr) {
+		errno = EINVAL;
+		return -1;
+	}
+	attr->max_nr_ranges = max_nr_ranges;
+	return 0;
+}
+
 int rseq_mempool_get_max_nr_cpus(struct rseq_mempool *mempool)
 {
 	if (!mempool || mempool->attr.type != MEMPOOL_TYPE_PERCPU) {
diff --git a/tests/mempool_test.c b/tests/mempool_test.c
index 6e19246..c55d3db 100644
--- a/tests/mempool_test.c
+++ b/tests/mempool_test.c
@@ -46,6 +46,8 @@ static void test_mempool_fill(size_t stride)
 	ok(ret == 0, "Setting mempool robust attribute");
 	ret = rseq_mempool_attr_set_percpu(attr, stride, CPU_SETSIZE);
 	ok(ret == 0, "Setting mempool percpu type");
+	ret = rseq_mempool_attr_set_max_nr_ranges(attr, 1);
+	ok(ret == 0, "Setting mempool max_nr_ranges=1");
 	mempool = rseq_mempool_create("test_data",
 			sizeof(struct test_data), attr);
 	ok(mempool, "Create mempool of size %zu", stride);