tests: add test for mempool logic

src/test/meson.build

@@ -509,6 +509,8 @@ tests += [
 
         [files('test-tpm2.c')],
 
+        [files('test-mempool.c')],
+
         [files('test-replace-var.c')],
 
         [files('test-calendarspec.c')],

src/test/test-mempool.c

@@ -0,0 +1,92 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "mempool.h"
+#include "random-util.h"
+#include "tests.h"
+
+struct element {
+        uint64_t value;
+};
+
+DEFINE_MEMPOOL(test_mempool, struct element, 8);
+
+TEST(mempool_trim) {
+
+#define NN 4000
+        struct element *a[NN];
+        size_t n_freed = 0;
+
+        assert_se(!test_mempool.first_pool);
+        assert_se(!test_mempool.freelist);
+
+        mempool_trim(&test_mempool);
+
+        for (size_t i = 0; i < NN; i++) {
+                assert_se(a[i] = mempool_alloc_tile(&test_mempool));
+                a[i]->value = i;
+        }
+
+        mempool_trim(&test_mempool);
+
+        /* free up to one third randomly */
+        size_t x = 0;
+        for (size_t i = 0; i < NN/3; i++) {
+                x = (x + random_u64()) % ELEMENTSOF(a);
+                assert_se(!a[x] || a[x]->value == x);
+
+                if (a[x])
+                        n_freed ++;
+
+                a[x] = mempool_free_tile(&test_mempool, a[x]);
+        }
+
+        mempool_trim(&test_mempool);
+
+        /* free definitely at least one third */
+        for (size_t i = 2; i < NN; i += 3) {
+                assert_se(!a[i] || a[i]->value == i);
+                if (a[i])
+                        n_freed ++;
+                a[i] = mempool_free_tile(&test_mempool, a[i]);
+        }
+
+        mempool_trim(&test_mempool);
+
+        /* Allocate another set of tiles, which will fill up the free list and allocate some new tiles */
+        struct element *b[NN];
+        for (size_t i = 0; i < NN; i++) {
+                assert_se(b[i] = mempool_alloc_tile(&test_mempool));
+                b[i]->value = ~(uint64_t) i;
+        }
+
+        mempool_trim(&test_mempool);
+
+        /* free everything from the original set*/
+
+        for (size_t i = 0; i < NN; i += 1) {
+                assert_se(!a[i] || a[i]->value == i);
+                if (a[i])
+                        n_freed ++;
+                a[i] = mempool_free_tile(&test_mempool, a[i]);
+        }
+
+        mempool_trim(&test_mempool);
+
+        /* and now everything from the second set too */
+
+        for (size_t i = 0; i < NN; i += 1) {
+                assert_se(!b[i] || b[i]->value == ~(uint64_t) i);
+                if (b[i])
+                        n_freed ++;
+                b[i] = mempool_free_tile(&test_mempool, b[i]);
+        }
+
+        assert_se(n_freed == NN * 2);
+
+        mempool_trim(&test_mempool);
+
+        assert_se(!test_mempool.first_pool);
+        assert_se(!test_mempool.freelist);
+}
+
+DEFINE_TEST_MAIN(LOG_DEBUG);