Make it possible to create memory contexts backed by jemalloc arenas

This commit extends the internal memory management middleware code in
BIND so that memory contexts backed by dedicated jemalloc arenas can
be created. A new function (isc_mem_create_arena()) is added for that.

Moreover, it extends the existing code so that specialised memory
contexts can be created easily, should we need that functionality for
other future purposes. We have achieved that by passing the flags to
the underlying jemalloc-related calls. See the above
isc_mem_create_arena(), which can serve as an example of this.

Having this opens up possibilities for creating memory contexts tuned
for specific needs.

lib/isc/include/isc/mem.h

@@ -197,6 +197,17 @@ isc__mem_create(isc_mem_t **_ISC_MEM_FLARG);
  * mctxp != NULL && *mctxp == NULL */
 /*@}*/
 
+#define isc_mem_create_arena(cp) isc__mem_create_arena((cp)_ISC_MEM_FILELINE)
+void
+isc__mem_create_arena(isc_mem_t **_ISC_MEM_FLARG);
+/*!<
+ * \brief Create a memory context that routs all its operations to a dedicated
+ * jemalloc arena (when available).
+ *
+ * Requires:
+ * mctxp != NULL && *mctxp == NULL */
+/*@}*/
+
 /*@{*/
 void
 isc_mem_attach(isc_mem_t *, isc_mem_t **);

lib/isc/jemalloc_shim.h

@@ -22,7 +22,9 @@
 
 const char *malloc_conf = NULL;
 
-#define MALLOCX_ZERO ((int)0x40)
+#define MALLOCX_ZERO	    ((int)0x40)
+#define MALLOCX_TCACHE_NONE (0)
+#define MALLOCX_ARENA(a)    (0)
 
 #if defined(HAVE_MALLOC_SIZE) || defined(HAVE_MALLOC_USABLE_SIZE)
 

lib/isc/mem.c

@@ -72,6 +72,8 @@
 unsigned int isc_mem_debugging = ISC_MEM_DEBUGGING;
 unsigned int isc_mem_defaultflags = ISC_MEMFLAG_DEFAULT;
 
+#define ISC_MEM_ILLEGAL_ARENA (UINT_MAX)
+
 /*
  * Constants.
  */
@@ -122,6 +124,8 @@ static isc_mutex_t contextslock;
 struct isc_mem {
 	unsigned int magic;
 	unsigned int flags;
+	unsigned int jemalloc_flags;
+	unsigned int jemalloc_arena;
 	unsigned int debugging;
 	isc_mutex_t lock;
 	bool checkfree;
@@ -225,7 +229,7 @@ add_trace_entry(isc_mem_t *mctx, const void *ptr, size_t size FLARG) {
 #endif
 	idx = hash % DEBUG_TABLE_COUNT;
 
-	dl = mallocx(sizeof(debuglink_t), 0);
+	dl = mallocx(sizeof(debuglink_t), mctx->jemalloc_flags);
 	INSIST(dl != NULL);
 
 	ISC_LINK_INIT(dl, link);
@@ -273,7 +277,7 @@ delete_trace_entry(isc_mem_t *mctx, const void *ptr, size_t size,
 	while (dl != NULL) {
 		if (dl->ptr == ptr) {
 			ISC_LIST_UNLINK(mctx->debuglist[idx], dl, link);
-			sdallocx(dl, sizeof(*dl), 0);
+			sdallocx(dl, sizeof(*dl), mctx->jemalloc_flags);
 			goto unlock;
 		}
 		dl = ISC_LIST_NEXT(dl, link);
@@ -303,7 +307,7 @@ mem_get(isc_mem_t *ctx, size_t size, int flags) {
 
 	ADJUST_ZERO_ALLOCATION_SIZE(size);
 
-	ret = mallocx(size, flags);
+	ret = mallocx(size, flags | ctx->jemalloc_flags);
 	INSIST(ret != NULL);
 
 	if ((flags & ISC__MEM_ZERO) == 0 &&
@@ -326,7 +330,7 @@ mem_put(isc_mem_t *ctx, void *mem, size_t size, int flags) {
 	if ((ctx->flags & ISC_MEMFLAG_FILL) != 0) {
 		memset(mem, 0xde, size); /* Mnemonic for "dead". */
 	}
-	sdallocx(mem, size, flags);
+	sdallocx(mem, size, flags | ctx->jemalloc_flags);
 }
 
 static void *
@@ -336,7 +340,7 @@ mem_realloc(isc_mem_t *ctx, void *old_ptr, size_t old_size, size_t new_size,
 
 	ADJUST_ZERO_ALLOCATION_SIZE(new_size);
 
-	new_ptr = rallocx(old_ptr, new_size, flags);
+	new_ptr = rallocx(old_ptr, new_size, flags | ctx->jemalloc_flags);
 	INSIST(new_ptr != NULL);
 
 	if ((flags & ISC__MEM_ZERO) == 0 &&
@@ -379,6 +383,48 @@ mem_putstats(isc_mem_t *ctx, size_t size) {
  * Private.
  */
 
+static bool
+mem_jemalloc_arena_create(unsigned int *pnew_arenano) {
+	REQUIRE(pnew_arenano != NULL);
+
+#ifdef JEMALLOC_API_SUPPORTED
+	unsigned int arenano = 0;
+	size_t len = sizeof(arenano);
+	int res = 0;
+
+	res = mallctl("arenas.create", &arenano, &len, NULL, 0);
+	if (res != 0) {
+		return (false);
+	}
+
+	*pnew_arenano = arenano;
+
+	return (true);
+#else
+	*pnew_arenano = ISC_MEM_ILLEGAL_ARENA;
+	return (true);
+#endif /* JEMALLOC_API_SUPPORTED */
+}
+
+static bool
+mem_jemalloc_arena_destroy(unsigned int arenano) {
+#ifdef JEMALLOC_API_SUPPORTED
+	int res = 0;
+	char buf[256] = { 0 };
+
+	(void)snprintf(buf, sizeof(buf), "arena.%u.destroy", arenano);
+	res = mallctl(buf, NULL, NULL, NULL, 0);
+	if (res != 0) {
+		return (false);
+	}
+
+	return (true);
+#else
+	UNUSED(arenano);
+	return (true);
+#endif /* JEMALLOC_API_SUPPORTED */
+}
+
 static void
 mem_initialize(void) {
 /*
@@ -410,18 +456,21 @@ isc__mem_shutdown(void) {
 }
 
 static void
-mem_create(isc_mem_t **ctxp, unsigned int debugging, unsigned int flags) {
+mem_create(isc_mem_t **ctxp, unsigned int debugging, unsigned int flags,
+	   unsigned int jemalloc_flags) {
 	isc_mem_t *ctx = NULL;
 
 	REQUIRE(ctxp != NULL && *ctxp == NULL);
 
-	ctx = malloc(sizeof(*ctx));
+	ctx = mallocx(sizeof(*ctx), jemalloc_flags);
 	INSIST(ctx != NULL);
 
 	*ctx = (isc_mem_t){
 		.magic = MEM_MAGIC,
 		.debugging = debugging,
 		.flags = flags,
+		.jemalloc_flags = jemalloc_flags,
+		.jemalloc_arena = ISC_MEM_ILLEGAL_ARENA,
 		.checkfree = true,
 	};
 
@@ -440,7 +489,9 @@ mem_create(isc_mem_t **ctxp, unsigned int debugging, unsigned int flags) {
 	if ((ctx->debugging & ISC_MEM_DEBUGRECORD) != 0) {
 		unsigned int i;
 
-		ctx->debuglist = calloc(DEBUG_TABLE_COUNT, sizeof(debuglist_t));
+		ctx->debuglist = mallocx(
+			ISC_CHECKED_MUL(DEBUG_TABLE_COUNT, sizeof(debuglist_t)),
+			jemalloc_flags);
 		INSIST(ctx->debuglist != NULL);
 
 		for (i = 0; i < DEBUG_TABLE_COUNT; i++) {
@@ -462,12 +513,15 @@ mem_create(isc_mem_t **ctxp, unsigned int debugging, unsigned int flags) {
 
 static void
 destroy(isc_mem_t *ctx) {
+	unsigned int arena_no;
 	LOCK(&contextslock);
 	ISC_LIST_UNLINK(contexts, ctx, link);
 	UNLOCK(&contextslock);
 
 	ctx->magic = 0;
 
+	arena_no = ctx->jemalloc_arena;
+
 	INSIST(ISC_LIST_EMPTY(ctx->pools));
 
 #if ISC_MEM_TRACKLINES
@@ -483,11 +537,14 @@ destroy(isc_mem_t *ctx) {
 				INSIST(!ctx->checkfree || dl->ptr == NULL);
 
 				ISC_LIST_UNLINK(ctx->debuglist[i], dl, link);
-				sdallocx(dl, sizeof(*dl), 0);
+				sdallocx(dl, sizeof(*dl), ctx->jemalloc_flags);
 			}
 		}
 
-		free(ctx->debuglist);
+		sdallocx(
+			ctx->debuglist,
+			ISC_CHECKED_MUL(DEBUG_TABLE_COUNT, sizeof(debuglist_t)),
+			ctx->jemalloc_flags);
 	}
 #endif /* if ISC_MEM_TRACKLINES */
 
@@ -496,7 +553,11 @@ destroy(isc_mem_t *ctx) {
 	if (ctx->checkfree) {
 		INSIST(atomic_load(&ctx->inuse) == 0);
 	}
-	free(ctx);
+	sdallocx(ctx, sizeof(*ctx), ctx->jemalloc_flags);
+
+	if (arena_no != ISC_MEM_ILLEGAL_ARENA) {
+		RUNTIME_CHECK(mem_jemalloc_arena_destroy(arena_no) == true);
+	}
 }
 
 void
@@ -806,7 +867,7 @@ isc__mem_allocate(isc_mem_t *ctx, size_t size, int flags FLARG) {
 	ptr = mem_get(ctx, size, flags);
 
 	/* Recalculate the real allocated size */
-	size = sallocx(ptr, flags);
+	size = sallocx(ptr, flags | ctx->jemalloc_flags);
 
 	mem_getstats(ctx, size);
 	ADD_TRACE(ctx, ptr, size, file, line);
@@ -859,7 +920,7 @@ isc__mem_reallocate(isc_mem_t *ctx, void *old_ptr, size_t new_size,
 	} else if (new_size == 0) {
 		isc__mem_free(ctx, old_ptr, flags FLARG_PASS);
 	} else {
-		size_t old_size = sallocx(old_ptr, flags);
+		size_t old_size = sallocx(old_ptr, flags | ctx->jemalloc_flags);
 
 		DELETE_TRACE(ctx, old_ptr, old_size, file, line);
 		mem_putstats(ctx, old_size);
@@ -867,7 +928,7 @@ isc__mem_reallocate(isc_mem_t *ctx, void *old_ptr, size_t new_size,
 		new_ptr = mem_realloc(ctx, old_ptr, old_size, new_size, flags);
 
 		/* Recalculate the real allocated size */
-		new_size = sallocx(new_ptr, flags);
+		new_size = sallocx(new_ptr, flags | ctx->jemalloc_flags);
 
 		mem_getstats(ctx, new_size);
 		ADD_TRACE(ctx, new_ptr, new_size, file, line);
@@ -891,7 +952,7 @@ isc__mem_free(isc_mem_t *ctx, void *ptr, int flags FLARG) {
 	REQUIRE(VALID_CONTEXT(ctx));
 	REQUIRE(ptr != NULL);
 
-	size = sallocx(ptr, flags);
+	size = sallocx(ptr, flags | ctx->jemalloc_flags);
 
 	DELETE_TRACE(ctx, ptr, size, file, line);
 
@@ -1542,7 +1603,7 @@ error:
 
 void
 isc__mem_create(isc_mem_t **mctxp FLARG) {
-	mem_create(mctxp, isc_mem_debugging, isc_mem_defaultflags);
+	mem_create(mctxp, isc_mem_debugging, isc_mem_defaultflags, 0);
 #if ISC_MEM_TRACKLINES
 	if ((isc_mem_debugging & ISC_MEM_DEBUGTRACE) != 0) {
 		fprintf(stderr, "create mctx %p file %s line %u\n", *mctxp,
@@ -1551,6 +1612,34 @@ isc__mem_create(isc_mem_t **mctxp FLARG) {
 #endif /* ISC_MEM_TRACKLINES */
 }
 
+void
+isc__mem_create_arena(isc_mem_t **mctxp FLARG) {
+	unsigned int arena_no = ISC_MEM_ILLEGAL_ARENA;
+
+	RUNTIME_CHECK(mem_jemalloc_arena_create(&arena_no));
+
+	/*
+	 * We use MALLOCX_TCACHE_NONE to bypass the tcache and route
+	 * allocations directly to the arena. That is a recommendation
+	 * from jemalloc developers:
+	 *
+	 * https://github.com/jemalloc/jemalloc/issues/2483#issuecomment-1698173849
+	 */
+	mem_create(mctxp, isc_mem_debugging, isc_mem_defaultflags,
+		   arena_no == ISC_MEM_ILLEGAL_ARENA
+			   ? 0
+			   : MALLOCX_ARENA(arena_no) | MALLOCX_TCACHE_NONE);
+	(*mctxp)->jemalloc_arena = arena_no;
+#if ISC_MEM_TRACKLINES
+	if ((isc_mem_debugging & ISC_MEM_DEBUGTRACE) != 0) {
+		fprintf(stderr,
+			"create mctx %p file %s line %u for jemalloc arena "
+			"%u\n",
+			*mctxp, file, line, arena_no);
+	}
+#endif /* ISC_MEM_TRACKLINES */
+}
+
 void
 isc__mem_printactive(isc_mem_t *ctx, FILE *file) {
 #if ISC_MEM_TRACKLINES