Remove --enable-tunables configure option

And make always supported.  The configure option was added on glibc 2.25
and some features require it (such as hwcap mask, huge pages support, and
lock elisition tuning).  It also simplifies the build permutations.

Changes from v1:
 * Remove glibc.rtld.dynamic_sort changes, it is orthogonal and needs
   more discussion.
 * Cleanup more code.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

4 files changed, 5 insertions, 137 deletions

diff --git a/malloc/Makefile b/malloc/Makefile
index f685fc6e6c..0717df626e 100644
--- a/malloc/Makefile
+++ b/malloc/Makefile
@@ -61,9 +61,7 @@ tests-internal += \
 	 tst-dynarray-fail \
 	 tst-dynarray-at-fail \
 
-ifneq (no,$(have-tunables))
 tests += tst-malloc-usable-tunables tst-mxfast
-endif
 
 tests += $(tests-static)
 test-srcs = tst-mtrace
diff --git a/malloc/arena.c b/malloc/arena.c
index ccd193953b..e98b779dbb 100644
--- a/malloc/arena.c
+++ b/malloc/arena.c
@@ -18,9 +18,7 @@
 
 #include <stdbool.h>
 
-#if HAVE_TUNABLES
-# define TUNABLE_NAMESPACE malloc
-#endif
+#define TUNABLE_NAMESPACE malloc
 #include <elf/dl-tunables.h>
 
 /* Compile-time constants.  */
@@ -47,21 +45,13 @@
 static inline size_t
 heap_min_size (void)
 {
-#if HAVE_TUNABLES
   return mp_.hp_pagesize == 0 ? HEAP_MIN_SIZE : mp_.hp_pagesize;
-#else
-  return HEAP_MIN_SIZE;
-#endif
 }
 
 static inline size_t
 heap_max_size (void)
 {
-#if HAVE_TUNABLES
   return mp_.hp_pagesize == 0 ? HEAP_MAX_SIZE : mp_.hp_pagesize * 4;
-#else
-  return HEAP_MAX_SIZE;
-#endif
 }
 
 /***************************************************************************/
@@ -239,8 +229,7 @@ __malloc_fork_unlock_child (void)
   __libc_lock_init (list_lock);
 }
 
-#if HAVE_TUNABLES
-# define TUNABLE_CALLBACK_FNDECL(__name, __type) \
+#define TUNABLE_CALLBACK_FNDECL(__name, __type) \
 static inline int do_ ## __name (__type value);				      \
 static void									      \
 TUNABLE_CALLBACK (__name) (tunable_val_t *valp)				      \
@@ -263,42 +252,6 @@ TUNABLE_CALLBACK_FNDECL (set_tcache_unsorted_limit, size_t)
 #endif
 TUNABLE_CALLBACK_FNDECL (set_mxfast, size_t)
 TUNABLE_CALLBACK_FNDECL (set_hugetlb, size_t)
-#else
-/* Initialization routine. */
-#include <string.h>
-extern char **_environ;
-
-static char *
-next_env_entry (char ***position)
-{
-  char **current = *position;
-  char *result = NULL;
-
-  while (*current != NULL)
-    {
-      if (__builtin_expect ((*current)[0] == 'M', 0)
-          && (*current)[1] == 'A'
-          && (*current)[2] == 'L'
-          && (*current)[3] == 'L'
-          && (*current)[4] == 'O'
-          && (*current)[5] == 'C'
-          && (*current)[6] == '_')
-        {
-          result = &(*current)[7];
-
-          /* Save current position for next visit.  */
-          *position = ++current;
-
-          break;
-        }
-
-      ++current;
-    }
-
-  return result;
-}
-#endif
-
 
 #if USE_TCACHE
 static void tcache_key_initialize (void);
@@ -343,7 +296,6 @@ ptmalloc_init (void)
 
   malloc_init_state (&main_arena);
 
-#if HAVE_TUNABLES
   TUNABLE_GET (top_pad, size_t, TUNABLE_CALLBACK (set_top_pad));
   TUNABLE_GET (perturb, int32_t, TUNABLE_CALLBACK (set_perturb_byte));
   TUNABLE_GET (mmap_threshold, size_t, TUNABLE_CALLBACK (set_mmap_threshold));
@@ -363,70 +315,6 @@ ptmalloc_init (void)
     /* Force mmap for main arena instead of sbrk, so hugepages are explicitly
        used.  */
     __always_fail_morecore = true;
-#else
-  if (__glibc_likely (_environ != NULL))
-    {
-      char **runp = _environ;
-      char *envline;
-
-      while (__builtin_expect ((envline = next_env_entry (&runp)) != NULL,
-                               0))
-        {
-          size_t len = strcspn (envline, "=");
-
-          if (envline[len] != '=')
-            /* This is a "MALLOC_" variable at the end of the string
-               without a '=' character.  Ignore it since otherwise we
-               will access invalid memory below.  */
-            continue;
-
-          switch (len)
-            {
-            case 8:
-              if (!__builtin_expect (__libc_enable_secure, 0))
-                {
-                  if (memcmp (envline, "TOP_PAD_", 8) == 0)
-                    __libc_mallopt (M_TOP_PAD, strtol (&envline[9], NULL, 10));
-                  else if (memcmp (envline, "PERTURB_", 8) == 0)
-                    __libc_mallopt (M_PERTURB, strtol (&envline[9], NULL, 10));
-                }
-              break;
-            case 9:
-              if (!__builtin_expect (__libc_enable_secure, 0))
-                {
-                  if (memcmp (envline, "MMAP_MAX_", 9) == 0)
-                    __libc_mallopt (M_MMAP_MAX, strtol (&envline[10],
-							NULL, 10));
-                  else if (memcmp (envline, "ARENA_MAX", 9) == 0)
-                    __libc_mallopt (M_ARENA_MAX, strtol (&envline[10],
-							 NULL, 10));
-                }
-              break;
-            case 10:
-              if (!__builtin_expect (__libc_enable_secure, 0))
-                {
-                  if (memcmp (envline, "ARENA_TEST", 10) == 0)
-                    __libc_mallopt (M_ARENA_TEST, strtol (&envline[11],
-							  NULL, 10));
-                }
-              break;
-            case 15:
-              if (!__builtin_expect (__libc_enable_secure, 0))
-                {
-                  if (memcmp (envline, "TRIM_THRESHOLD_", 15) == 0)
-                    __libc_mallopt (M_TRIM_THRESHOLD, strtol (&envline[16],
-							      NULL, 10));
-                  else if (memcmp (envline, "MMAP_THRESHOLD_", 15) == 0)
-                    __libc_mallopt (M_MMAP_THRESHOLD, strtol (&envline[16],
-							      NULL, 10));
-                }
-              break;
-            default:
-              break;
-            }
-        }
-    }
-#endif
 }
 
 /* Managing heaps and arenas (for concurrent threads) */
@@ -561,7 +449,6 @@ alloc_new_heap  (size_t size, size_t top_pad, size_t pagesize,
 static heap_info *
 new_heap (size_t size, size_t top_pad)
 {
-#if HAVE_TUNABLES
   if (__glibc_unlikely (mp_.hp_pagesize != 0))
     {
       heap_info *h = alloc_new_heap (size, top_pad, mp_.hp_pagesize,
@@ -569,7 +456,6 @@ new_heap (size_t size, size_t top_pad)
       if (h != NULL)
 	return h;
     }
-#endif
   return alloc_new_heap (size, top_pad, GLRO (dl_pagesize), 0);
 }
 
diff --git a/malloc/malloc-check.c b/malloc/malloc-check.c
index af27fd2c52..5732d81bf1 100644
--- a/malloc/malloc-check.c
+++ b/malloc/malloc-check.c
@@ -376,7 +376,6 @@ memalign_check (size_t alignment, size_t bytes)
   return mem2mem_check (tag_new_usable (mem), bytes);
 }
 
-#if HAVE_TUNABLES
 static void
 TUNABLE_CALLBACK (set_mallopt_check) (tunable_val_t *valp)
 {
@@ -384,7 +383,6 @@ TUNABLE_CALLBACK (set_mallopt_check) (tunable_val_t *valp)
   if (value != 0)
     __malloc_debug_enable (MALLOC_CHECK_HOOK);
 }
-#endif
 
 static bool
 initialize_malloc_check (void)
@@ -392,12 +390,6 @@ initialize_malloc_check (void)
   /* This is the copy of the malloc initializer that we pulled in along with
      malloc-check.  This does not affect any of the libc malloc structures.  */
   ptmalloc_init ();
-#if HAVE_TUNABLES
   TUNABLE_GET (check, int32_t, TUNABLE_CALLBACK (set_mallopt_check));
-#else
-  const char *s = secure_getenv ("MALLOC_CHECK_");
-  if (s && s[0] != '\0' && s[0] != '0')
-    __malloc_debug_enable (MALLOC_CHECK_HOOK);
-#endif
   return __is_malloc_debug_enabled (MALLOC_CHECK_HOOK);
 }
diff --git a/malloc/malloc.c b/malloc/malloc.c
index 76c50e3f58..05e65a2d54 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -1856,14 +1856,12 @@ struct malloc_par
   INTERNAL_SIZE_T arena_test;
   INTERNAL_SIZE_T arena_max;
 
-#if HAVE_TUNABLES
   /* Transparent Large Page support.  */
   INTERNAL_SIZE_T thp_pagesize;
   /* A value different than 0 means to align mmap allocation to hp_pagesize
      add hp_flags on flags.  */
   INTERNAL_SIZE_T hp_pagesize;
   int hp_flags;
-#endif
 
   /* Memory map support */
   int n_mmaps;
@@ -1998,7 +1996,7 @@ free_perturb (char *p, size_t n)
 static inline void
 madvise_thp (void *p, INTERNAL_SIZE_T size)
 {
-#if HAVE_TUNABLES && defined (MADV_HUGEPAGE)
+#ifdef MADV_HUGEPAGE
   /* Do not consider areas smaller than a huge page or if the tunable is
      not active.  */
   if (mp_.thp_pagesize == 0 || size < mp_.thp_pagesize)
@@ -2557,7 +2555,6 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av)
 	  && (mp_.n_mmaps < mp_.n_mmaps_max)))
     {
       char *mm;
-#if HAVE_TUNABLES
       if (mp_.hp_pagesize > 0 && nb >= mp_.hp_pagesize)
 	{
 	  /* There is no need to isse the THP madvise call if Huge Pages are
@@ -2566,7 +2563,6 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av)
 	  if (mm != MAP_FAILED)
 	    return mm;
 	}
-#endif
       mm = sysmalloc_mmap (nb, pagesize, 0, av);
       if (mm != MAP_FAILED)
 	return mm;
@@ -2679,7 +2675,7 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av)
          previous calls. Otherwise, we correct to page-align below.
        */
 
-#if HAVE_TUNABLES && defined (MADV_HUGEPAGE)
+#ifdef MADV_HUGEPAGE
       /* Defined in brk.c.  */
       extern void *__curbrk;
       if (__glibc_unlikely (mp_.thp_pagesize != 0))
@@ -2718,12 +2714,10 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av)
            */
 
 	  char *mbrk = MAP_FAILED;
-#if HAVE_TUNABLES
 	  if (mp_.hp_pagesize > 0)
 	    mbrk = sysmalloc_mmap_fallback (&size, nb, old_size,
 					    mp_.hp_pagesize, mp_.hp_pagesize,
 					    mp_.hp_flags, av);
-#endif
 	  if (mbrk == MAP_FAILED)
 	    mbrk = sysmalloc_mmap_fallback (&size, nb, old_size, MMAP_AS_MORECORE_SIZE,
 					    pagesize, 0, av);
@@ -2966,7 +2960,7 @@ systrim (size_t pad, mstate av)
     return 0;
 
   /* Release in pagesize units and round down to the nearest page.  */
-#if HAVE_TUNABLES && defined (MADV_HUGEPAGE)
+#ifdef MADV_HUGEPAGE
   if (__glibc_unlikely (mp_.thp_pagesize != 0))
     extra = ALIGN_DOWN (top_area - pad, mp_.thp_pagesize);
   else
@@ -5410,7 +5404,6 @@ do_set_mxfast (size_t value)
   return 0;
 }
 
-#if HAVE_TUNABLES
 static __always_inline int
 do_set_hugetlb (size_t value)
 {
@@ -5429,7 +5422,6 @@ do_set_hugetlb (size_t value)
 			      &mp_.hp_flags);
   return 0;
 }
-#endif
 
 int
 __libc_mallopt (int param_number, int value)