Add a per-arena oversize_threshold.

This can let manual arenas trade off memory and CPU the way auto arenas do.

test/unit/oversize_threshold.c

@@ -0,0 +1,131 @@
+#include "test/jemalloc_test.h"
+
+#include "jemalloc/internal/ctl.h"
+
+static void
+arena_mallctl(const char *mallctl_str, unsigned arena, void *oldp,
+    size_t *oldlen, void *newp, size_t newlen) {
+	int err;
+	char buf[100];
+	malloc_snprintf(buf, sizeof(buf), mallctl_str, arena);
+
+	err = mallctl(buf, oldp, oldlen, newp, newlen);
+	expect_d_eq(0, err, "Mallctl failed; %s", buf);
+}
+
+TEST_BEGIN(test_oversize_threshold_get_set) {
+	int err;
+	size_t old_threshold;
+	size_t new_threshold;
+	size_t threshold_sz = sizeof(old_threshold);
+
+	unsigned arena;
+	size_t arena_sz = sizeof(arena);
+	err = mallctl("arenas.create", (void *)&arena, &arena_sz, NULL, 0);
+	expect_d_eq(0, err, "Arena creation failed");
+
+	/* Just a write. */
+	new_threshold = 1024 * 1024;
+	arena_mallctl("arena.%u.oversize_threshold", arena, NULL, NULL,
+	    &new_threshold, threshold_sz);
+
+	/* Read and write */
+	new_threshold = 2 * 1024 * 1024;
+	arena_mallctl("arena.%u.oversize_threshold", arena, &old_threshold,
+	    &threshold_sz, &new_threshold, threshold_sz);
+	expect_zu_eq(1024 * 1024, old_threshold, "Should have read old value");
+
+	/* Just a read */
+	arena_mallctl("arena.%u.oversize_threshold", arena, &old_threshold,
+	    &threshold_sz, NULL, 0);
+	expect_zu_eq(2 * 1024 * 1024, old_threshold, "Should have read old value");
+}
+TEST_END
+
+static size_t max_purged = 0;
+static bool
+purge_forced_record_max(extent_hooks_t* hooks, void *addr, size_t sz,
+    size_t offset, size_t length, unsigned arena_ind) {
+	if (length > max_purged) {
+		max_purged = length;
+	}
+	return false;
+}
+
+static bool
+dalloc_record_max(extent_hooks_t *extent_hooks, void *addr, size_t sz,
+    bool comitted, unsigned arena_ind) {
+	if (sz > max_purged) {
+		max_purged = sz;
+	}
+	return false;
+}
+
+extent_hooks_t max_recording_extent_hooks;
+
+TEST_BEGIN(test_oversize_threshold) {
+	max_recording_extent_hooks = ehooks_default_extent_hooks;
+	max_recording_extent_hooks.purge_forced = &purge_forced_record_max;
+	max_recording_extent_hooks.dalloc = &dalloc_record_max;
+
+	extent_hooks_t *extent_hooks = &max_recording_extent_hooks;
+
+	int err;
+
+	unsigned arena;
+	size_t arena_sz = sizeof(arena);
+	err = mallctl("arenas.create", (void *)&arena, &arena_sz, NULL, 0);
+	expect_d_eq(0, err, "Arena creation failed");
+	arena_mallctl("arena.%u.extent_hooks", arena, NULL, NULL, &extent_hooks,
+	    sizeof(extent_hooks));
+
+	/*
+	 * This test will fundamentally race with purging, since we're going to
+	 * check the dirty stats to see if our oversized allocation got purged.
+	 * We don't want other purging to happen accidentally.  We can't just
+	 * disable purging entirely, though, since that will also disable
+	 * oversize purging.  Just set purging intervals to be very large.
+	 */
+	ssize_t decay_ms = 100 * 1000;
+	ssize_t decay_ms_sz = sizeof(decay_ms);
+	arena_mallctl("arena.%u.dirty_decay_ms", arena, NULL, NULL, &decay_ms,
+	    decay_ms_sz);
+	arena_mallctl("arena.%u.muzzy_decay_ms", arena, NULL, NULL, &decay_ms,
+	    decay_ms_sz);
+
+	/* Clean everything out. */
+	arena_mallctl("arena.%u.purge", arena, NULL, NULL, NULL, 0);
+	max_purged = 0;
+
+	/* Set threshold to 1MB. */
+	size_t threshold = 1024 * 1024;
+	size_t threshold_sz = sizeof(threshold);
+	arena_mallctl("arena.%u.oversize_threshold", arena, NULL, NULL,
+	    &threshold, threshold_sz);
+
+	/* Allocating and freeing half a megabyte should leave them dirty. */
+	void *ptr = mallocx(512 * 1024, MALLOCX_ARENA(arena));
+	dallocx(ptr, MALLOCX_TCACHE_NONE);
+	expect_zu_lt(max_purged, 512 * 1024, "Expected no 512k purge");
+
+	/* Purge again to reset everything out. */
+	arena_mallctl("arena.%u.purge", arena, NULL, NULL, NULL, 0);
+	max_purged = 0;
+
+	/*
+	 * Allocating and freeing 2 megabytes should leave them dirty because of
+	 * the oversize threshold.
+	 */
+	ptr = mallocx(2 * 1024 * 1024, MALLOCX_ARENA(arena));
+	dallocx(ptr, MALLOCX_TCACHE_NONE);
+	expect_zu_ge(max_purged, 2 * 1024 * 1024, "Expected a 2MB purge");
+}
+TEST_END
+
+int
+main(void) {
+	return test_no_reentrancy(
+	    test_oversize_threshold_get_set,
+	    test_oversize_threshold);
+}
+

test/unit/pa.c

@@ -63,9 +63,11 @@ test_data_t *init_test_data(ssize_t dirty_decay_ms, ssize_t muzzy_decay_ms) {
 	nstime_t time;
 	nstime_init(&time, 0);
 
+	const size_t oversize_threshold = 8 * 1024 * 1024;
 	err = pa_shard_init(TSDN_NULL, &test_data->shard, &test_data->emap,
 	    test_data->base, /* ind */ 1, &test_data->stats,
-	    &test_data->stats_mtx, &time, dirty_decay_ms, muzzy_decay_ms);
+	    &test_data->stats_mtx, &time, oversize_threshold, dirty_decay_ms,
+	    muzzy_decay_ms);
 	assert_false(err, "");
 
 	return test_data;