Add packing test, which verifies stable layout policy.

Makefile.in

@@ -160,6 +160,7 @@ TESTS_UNIT := \
 	$(srcroot)test/unit/math.c \
 	$(srcroot)test/unit/mq.c \
 	$(srcroot)test/unit/mtx.c \
+	$(srcroot)test/unit/pack.c \
 	$(srcroot)test/unit/ph.c \
 	$(srcroot)test/unit/prng.c \
 	$(srcroot)test/unit/prof_accum.c \

test/unit/pack.c

@@ -0,0 +1,167 @@
+#include "test/jemalloc_test.h"
+
+/* Immediately purge to minimize fragmentation. */
+const char *malloc_conf = "decay_time:-1";
+
+/*
+ * Size class that is a divisor of the page size, ideally 4+ regions per run.
+ */
+#if LG_PAGE <= 14
+#define	SZ	(ZU(1) << (LG_PAGE - 2))
+#else
+#define	SZ	4096
+#endif
+
+/*
+ * Number of slabs to consume at high water mark.  Should be at least 2 so that
+ * if mmap()ed memory grows downward, downward growth of mmap()ed memory is
+ * tested.
+ */
+#define	NSLABS	8
+
+static unsigned
+binind_compute(void)
+{
+	size_t sz;
+	unsigned nbins, i;
+
+	sz = sizeof(nbins);
+	assert_d_eq(mallctl("arenas.nbins", &nbins, &sz, NULL, 0), 0,
+	    "Unexpected mallctl failure");
+
+	for (i = 0; i < nbins; i++) {
+		size_t mib[4];
+		size_t miblen = sizeof(mib)/sizeof(size_t);
+		size_t size;
+
+		assert_d_eq(mallctlnametomib("arenas.bin.0.size", mib,
+		    &miblen), 0, "Unexpected mallctlnametomb failure");
+		mib[2] = (size_t)i;
+
+		sz = sizeof(size);
+		assert_d_eq(mallctlbymib(mib, miblen, &size, &sz, NULL, 0), 0,
+		    "Unexpected mallctlbymib failure");
+		if (size == SZ)
+			return (i);
+	}
+
+	test_fail("Unable to compute nregs_per_run");
+	return (0);
+}
+
+static size_t
+nregs_per_run_compute(void)
+{
+	uint32_t nregs;
+	size_t sz;
+	unsigned binind = binind_compute();
+	size_t mib[4];
+	size_t miblen = sizeof(mib)/sizeof(size_t);
+
+	assert_d_eq(mallctlnametomib("arenas.bin.0.nregs", mib, &miblen), 0,
+	    "Unexpected mallctlnametomb failure");
+	mib[2] = (size_t)binind;
+	sz = sizeof(nregs);
+	assert_d_eq(mallctlbymib(mib, miblen, &nregs, &sz, NULL,
+	    0), 0, "Unexpected mallctlbymib failure");
+	return (nregs);
+}
+
+static unsigned
+arenas_extend_mallctl(void)
+{
+	unsigned arena_ind;
+	size_t sz;
+
+	sz = sizeof(arena_ind);
+	assert_d_eq(mallctl("arenas.extend", &arena_ind, &sz, NULL, 0), 0,
+	    "Error in arenas.extend");
+
+	return (arena_ind);
+}
+
+static void
+arena_reset_mallctl(unsigned arena_ind)
+{
+	size_t mib[3];
+	size_t miblen = sizeof(mib)/sizeof(size_t);
+
+	assert_d_eq(mallctlnametomib("arena.0.reset", mib, &miblen), 0,
+	    "Unexpected mallctlnametomib() failure");
+	mib[1] = (size_t)arena_ind;
+	assert_d_eq(mallctlbymib(mib, miblen, NULL, NULL, NULL, 0), 0,
+	    "Unexpected mallctlbymib() failure");
+}
+
+TEST_BEGIN(test_pack)
+{
+	unsigned arena_ind = arenas_extend_mallctl();
+	size_t nregs_per_run = nregs_per_run_compute();
+	size_t nregs = nregs_per_run * NSLABS;
+	VARIABLE_ARRAY(void *, ptrs, nregs);
+	size_t i, j, offset;
+
+	/* Fill matrix. */
+	for (i = offset = 0; i < NSLABS; i++) {
+		for (j = 0; j < nregs_per_run; j++) {
+			void *p = mallocx(SZ, MALLOCX_ARENA(arena_ind) |
+			    MALLOCX_TCACHE_NONE);
+			assert_ptr_not_null(p,
+			    "Unexpected mallocx(%zu, MALLOCX_ARENA(%u) |"
+			    " MALLOCX_TCACHE_NONE) failure, run=%zu, reg=%zu",
+			    SZ, arena_ind, i, j);
+			ptrs[(i * nregs_per_run) + j] = p;
+		}
+	}
+
+	/*
+	 * Free all but one region of each run, but rotate which region is
+	 * preserved, so that subsequent allocations exercise the within-run
+	 * layout policy.
+	 */
+	offset = 0;
+	for (i = offset = 0;
+	    i < NSLABS;
+	    i++, offset = (offset + 1) % nregs_per_run) {
+		for (j = 0; j < nregs_per_run; j++) {
+			void *p = ptrs[(i * nregs_per_run) + j];
+			if (offset == j)
+				continue;
+			dallocx(p, MALLOCX_ARENA(arena_ind) |
+			    MALLOCX_TCACHE_NONE);
+		}
+	}
+
+	/*
+	 * Logically refill matrix, skipping preserved regions and verifying
+	 * that the matrix is unmodified.
+	 */
+	offset = 0;
+	for (i = offset = 0;
+	    i < NSLABS;
+	    i++, offset = (offset + 1) % nregs_per_run) {
+		for (j = 0; j < nregs_per_run; j++) {
+			void *p;
+
+			if (offset == j)
+				continue;
+			p = mallocx(SZ, MALLOCX_ARENA(arena_ind) |
+			    MALLOCX_TCACHE_NONE);
+			assert_ptr_eq(p, ptrs[(i * nregs_per_run) + j],
+			    "Unexpected refill discrepancy, run=%zu, reg=%zu\n",
+			    i, j);
+		}
+	}
+
+	/* Clean up. */
+	arena_reset_mallctl(arena_ind);
+}
+TEST_END
+
+int
+main(void)
+{
+
+	return (test(
+	    test_pack));
+}