jemalloc: remove THP support

This is not explored on Android properly and no one should use it until
proper scientific testing.

Moreover, THP is broken with all recent Qualcomm devices due to
speculative page faults.

Signed-off-by: Park Ju Hyung <qkrwngud825@gmail.com>
Change-Id: Ic1a2b9f17cef4b73d32102a4ae8704cc4654307b

23 files changed, 17 insertions, 387 deletions

diff --git a/Android.bp b/Android.bp
index 1dea6020..85768202 100644
--- a/Android.bp
+++ b/Android.bp
@@ -254,7 +254,6 @@ unit_tests = [
     "test/unit/mq.c",
     "test/unit/mtx.c",
     "test/unit/pack.c",
-    "test/unit/pages.c",
     "test/unit/ph.c",
     "test/unit/prng.c",
     "test/unit/prof_accum.c",
diff --git a/include/jemalloc/internal/arena_stats.h b/include/jemalloc/internal/arena_stats.h
index 23949ed9..50ec76a0 100644
--- a/include/jemalloc/internal/arena_stats.h
+++ b/include/jemalloc/internal/arena_stats.h
@@ -103,7 +103,6 @@ struct arena_stats_s {
 	atomic_zu_t		base; /* Derived. */
 	atomic_zu_t		internal;
 	atomic_zu_t		resident; /* Derived. */
-	atomic_zu_t		metadata_thp;
 
 	atomic_zu_t		allocated_large; /* Derived. */
 	arena_stats_u64_t	nmalloc_large; /* Derived. */
diff --git a/include/jemalloc/internal/base_externs.h b/include/jemalloc/internal/base_externs.h
index 7b705c9b..a4fd5ac7 100644
--- a/include/jemalloc/internal/base_externs.h
+++ b/include/jemalloc/internal/base_externs.h
@@ -1,9 +1,6 @@
 #ifndef JEMALLOC_INTERNAL_BASE_EXTERNS_H
 #define JEMALLOC_INTERNAL_BASE_EXTERNS_H
 
-extern metadata_thp_mode_t opt_metadata_thp;
-extern const char *metadata_thp_mode_names[];
-
 base_t *b0get(void);
 base_t *base_new(tsdn_t *tsdn, unsigned ind, extent_hooks_t *extent_hooks);
 void base_delete(tsdn_t *tsdn, base_t *base);
@@ -13,7 +10,7 @@ extent_hooks_t *base_extent_hooks_set(base_t *base,
 void *base_alloc(tsdn_t *tsdn, base_t *base, size_t size, size_t alignment);
 extent_t *base_alloc_extent(tsdn_t *tsdn, base_t *base);
 void base_stats_get(tsdn_t *tsdn, base_t *base, size_t *allocated,
-    size_t *resident, size_t *mapped, size_t *n_thp);
+    size_t *resident, size_t *mapped);
 void base_prefork(tsdn_t *tsdn, base_t *base);
 void base_postfork_parent(tsdn_t *tsdn, base_t *base);
 void base_postfork_child(tsdn_t *tsdn, base_t *base);
diff --git a/include/jemalloc/internal/base_inlines.h b/include/jemalloc/internal/base_inlines.h
index aec0e2e1..931560bf 100644
--- a/include/jemalloc/internal/base_inlines.h
+++ b/include/jemalloc/internal/base_inlines.h
@@ -6,8 +6,4 @@ base_ind_get(const base_t *base) {
 	return base->ind;
 }
 
-static inline bool
-metadata_thp_enabled(void) {
-	return (opt_metadata_thp != metadata_thp_disabled);
-}
 #endif /* JEMALLOC_INTERNAL_BASE_INLINES_H */
diff --git a/include/jemalloc/internal/base_structs.h b/include/jemalloc/internal/base_structs.h
index 07f214eb..0d729546 100644
--- a/include/jemalloc/internal/base_structs.h
+++ b/include/jemalloc/internal/base_structs.h
@@ -30,8 +30,6 @@ struct base_s {
 	/* Protects base_alloc() and base_stats_get() operations. */
 	malloc_mutex_t	mtx;
 
-	/* Using THP when true (metadata_thp auto mode). */
-	bool		auto_thp_switched;
 	/*
 	 * Most recent size class in the series of increasingly large base
 	 * extents.  Logarithmic spacing between subsequent allocations ensures
@@ -52,8 +50,6 @@ struct base_s {
 	size_t		allocated;
 	size_t		resident;
 	size_t		mapped;
-	/* Number of THP regions touched. */
-	size_t		n_thp;
 };
 
 #endif /* JEMALLOC_INTERNAL_BASE_STRUCTS_H */
diff --git a/include/jemalloc/internal/base_types.h b/include/jemalloc/internal/base_types.h
index b6db77df..be7ee825 100644
--- a/include/jemalloc/internal/base_types.h
+++ b/include/jemalloc/internal/base_types.h
@@ -4,30 +4,4 @@
 typedef struct base_block_s base_block_t;
 typedef struct base_s base_t;
 
-#define METADATA_THP_DEFAULT metadata_thp_disabled
-
-/*
- * In auto mode, arenas switch to huge pages for the base allocator on the
- * second base block.  a0 switches to thp on the 5th block (after 20 megabytes
- * of metadata), since more metadata (e.g. rtree nodes) come from a0's base.
- */
-
-#define BASE_AUTO_THP_THRESHOLD    2
-#define BASE_AUTO_THP_THRESHOLD_A0 5
-
-typedef enum {
-	metadata_thp_disabled   = 0,
-	/*
-	 * Lazily enable hugepage for metadata. To avoid high RSS caused by THP
-	 * + low usage arena (i.e. THP becomes a significant percentage), the
-	 * "auto" option only starts using THP after a base allocator used up
-	 * the first THP region.  Starting from the second hugepage (in a single
-	 * arena), "auto" behaves the same as "always", i.e. madvise hugepage
-	 * right away.
-	 */
-	metadata_thp_auto       = 1,
-	metadata_thp_always     = 2,
-	metadata_thp_mode_limit = 3
-} metadata_thp_mode_t;
-
 #endif /* JEMALLOC_INTERNAL_BASE_TYPES_H */
diff --git a/include/jemalloc/internal/ctl.h b/include/jemalloc/internal/ctl.h
index 1d1aacc6..3aaf5579 100644
--- a/include/jemalloc/internal/ctl.h
+++ b/include/jemalloc/internal/ctl.h
@@ -51,7 +51,6 @@ typedef struct ctl_stats_s {
 	size_t allocated;
 	size_t active;
 	size_t metadata;
-	size_t metadata_thp;
 	size_t resident;
 	size_t mapped;
 	size_t retained;
diff --git a/include/jemalloc/internal/jemalloc_internal_defs.h b/include/jemalloc/internal/jemalloc_internal_defs.h
index 4ab84453..4b9dfa4e 100644
--- a/include/jemalloc/internal/jemalloc_internal_defs.h
+++ b/include/jemalloc/internal/jemalloc_internal_defs.h
@@ -291,7 +291,7 @@
  * Defined if transparent huge pages are supported via the MADV_[NO]HUGEPAGE
  * arguments to madvise(2).
  */
-#define JEMALLOC_HAVE_MADVISE_HUGE 
+/* #undef JEMALLOC_HAVE_MADVISE_HUGE */
 
 /*
  * Methods for purging unused pages differ between operating systems.
@@ -319,12 +319,6 @@
  */
 #define JEMALLOC_MADVISE_DONTDUMP 
 
-/*
- * Defined if transparent huge pages (THPs) are supported via the
- * MADV_[NO]HUGEPAGE arguments to madvise(2), and THP support is enabled.
- */
-/* #undef JEMALLOC_THP */
-
 /* Define if operating system has alloca.h header. */
 #define JEMALLOC_HAS_ALLOCA_H 1
 
diff --git a/include/jemalloc/internal/jemalloc_internal_defs.h.in b/include/jemalloc/internal/jemalloc_internal_defs.h.in
index c442a219..a0c7eec3 100644
--- a/include/jemalloc/internal/jemalloc_internal_defs.h.in
+++ b/include/jemalloc/internal/jemalloc_internal_defs.h.in
@@ -290,12 +290,6 @@
  */
 #undef JEMALLOC_MADVISE_DONTDUMP
 
-/*
- * Defined if transparent huge pages (THPs) are supported via the
- * MADV_[NO]HUGEPAGE arguments to madvise(2), and THP support is enabled.
- */
-#undef JEMALLOC_THP
-
 /* Define if operating system has alloca.h header. */
 #undef JEMALLOC_HAS_ALLOCA_H
 
diff --git a/include/jemalloc/internal/jemalloc_internal_defs_host.h b/include/jemalloc/internal/jemalloc_internal_defs_host.h
index 38f91bc2..7cdb6521 100644
--- a/include/jemalloc/internal/jemalloc_internal_defs_host.h
+++ b/include/jemalloc/internal/jemalloc_internal_defs_host.h
@@ -302,12 +302,6 @@
  */
 /* #undef JEMALLOC_MADVISE_DONTDUMP */
 
-/*
- * Defined if transparent huge pages (THPs) are supported via the
- * MADV_[NO]HUGEPAGE arguments to madvise(2), and THP support is enabled.
- */
-/* #undef JEMALLOC_THP */
-
 /* Define if operating system has alloca.h header. */
 #define JEMALLOC_HAS_ALLOCA_H 1
 
diff --git a/include/jemalloc/internal/pages.h b/include/jemalloc/internal/pages.h
index 7dae633a..224b3013 100644
--- a/include/jemalloc/internal/pages.h
+++ b/include/jemalloc/internal/pages.h
@@ -58,20 +58,6 @@ static const bool pages_can_purge_forced =
 #endif
     ;
 
-typedef enum {
-	thp_mode_default       = 0, /* Do not change hugepage settings. */
-	thp_mode_always        = 1, /* Always set MADV_HUGEPAGE. */
-	thp_mode_never         = 2, /* Always set MADV_NOHUGEPAGE. */
-
-	thp_mode_names_limit   = 3, /* Used for option processing. */
-	thp_mode_not_supported = 3  /* No THP support detected. */
-} thp_mode_t;
-
-#define THP_MODE_DEFAULT thp_mode_default
-extern thp_mode_t opt_thp;
-extern thp_mode_t init_system_thp_mode; /* Initial system wide state. */
-extern const char *thp_mode_names[];
-
 void *pages_map(void *addr, size_t size, size_t alignment, bool *commit);
 void pages_unmap(void *addr, size_t size);
 bool pages_commit(void *addr, size_t size);
@@ -83,6 +69,5 @@ bool pages_nohuge(void *addr, size_t size);
 bool pages_dontdump(void *addr, size_t size);
 bool pages_dodump(void *addr, size_t size);
 bool pages_boot(void);
-void pages_set_thp_state (void *ptr, size_t size);
 
 #endif /* JEMALLOC_INTERNAL_PAGES_EXTERNS_H */
diff --git a/include/jemalloc/internal/private_namespace.h b/include/jemalloc/internal/private_namespace.h
index 8744f167..17d1475f 100644
--- a/include/jemalloc/internal/private_namespace.h
+++ b/include/jemalloc/internal/private_namespace.h
@@ -116,8 +116,6 @@
 #define base_postfork_parent JEMALLOC_N(base_postfork_parent)
 #define base_prefork JEMALLOC_N(base_prefork)
 #define base_stats_get JEMALLOC_N(base_stats_get)
-#define metadata_thp_mode_names JEMALLOC_N(metadata_thp_mode_names)
-#define opt_metadata_thp JEMALLOC_N(opt_metadata_thp)
 #define bin_infos JEMALLOC_N(bin_infos)
 #define bin_init JEMALLOC_N(bin_init)
 #define bin_postfork_child JEMALLOC_N(bin_postfork_child)
@@ -251,8 +249,6 @@
 #define nstime_sec JEMALLOC_N(nstime_sec)
 #define nstime_subtract JEMALLOC_N(nstime_subtract)
 #define nstime_update JEMALLOC_N(nstime_update)
-#define init_system_thp_mode JEMALLOC_N(init_system_thp_mode)
-#define opt_thp JEMALLOC_N(opt_thp)
 #define pages_boot JEMALLOC_N(pages_boot)
 #define pages_commit JEMALLOC_N(pages_commit)
 #define pages_decommit JEMALLOC_N(pages_decommit)
@@ -263,9 +259,7 @@
 #define pages_nohuge JEMALLOC_N(pages_nohuge)
 #define pages_purge_forced JEMALLOC_N(pages_purge_forced)
 #define pages_purge_lazy JEMALLOC_N(pages_purge_lazy)
-#define pages_set_thp_state JEMALLOC_N(pages_set_thp_state)
 #define pages_unmap JEMALLOC_N(pages_unmap)
-#define thp_mode_names JEMALLOC_N(thp_mode_names)
 #define bt2gctx_mtx JEMALLOC_N(bt2gctx_mtx)
 #define bt_init JEMALLOC_N(bt_init)
 #define lg_prof_sample JEMALLOC_N(lg_prof_sample)
diff --git a/include/jemalloc/internal/private_namespace_jet.h b/include/jemalloc/internal/private_namespace_jet.h
index c745f6ea..fce9a813 100644
--- a/include/jemalloc/internal/private_namespace_jet.h
+++ b/include/jemalloc/internal/private_namespace_jet.h
@@ -117,8 +117,6 @@
 #define base_postfork_parent JEMALLOC_N(base_postfork_parent)
 #define base_prefork JEMALLOC_N(base_prefork)
 #define base_stats_get JEMALLOC_N(base_stats_get)
-#define metadata_thp_mode_names JEMALLOC_N(metadata_thp_mode_names)
-#define opt_metadata_thp JEMALLOC_N(opt_metadata_thp)
 #define bin_infos JEMALLOC_N(bin_infos)
 #define bin_init JEMALLOC_N(bin_init)
 #define bin_postfork_child JEMALLOC_N(bin_postfork_child)
@@ -254,8 +252,6 @@
 #define nstime_sec JEMALLOC_N(nstime_sec)
 #define nstime_subtract JEMALLOC_N(nstime_subtract)
 #define nstime_update JEMALLOC_N(nstime_update)
-#define init_system_thp_mode JEMALLOC_N(init_system_thp_mode)
-#define opt_thp JEMALLOC_N(opt_thp)
 #define pages_boot JEMALLOC_N(pages_boot)
 #define pages_commit JEMALLOC_N(pages_commit)
 #define pages_decommit JEMALLOC_N(pages_decommit)
@@ -266,9 +262,7 @@
 #define pages_nohuge JEMALLOC_N(pages_nohuge)
 #define pages_purge_forced JEMALLOC_N(pages_purge_forced)
 #define pages_purge_lazy JEMALLOC_N(pages_purge_lazy)
-#define pages_set_thp_state JEMALLOC_N(pages_set_thp_state)
 #define pages_unmap JEMALLOC_N(pages_unmap)
-#define thp_mode_names JEMALLOC_N(thp_mode_names)
 #define bt2gctx_mtx JEMALLOC_N(bt2gctx_mtx)
 #define bt_init JEMALLOC_N(bt_init)
 #define lg_prof_sample JEMALLOC_N(lg_prof_sample)
diff --git a/src/arena.c b/src/arena.c
index 54842421..8b138c29 100644
--- a/src/arena.c
+++ b/src/arena.c
@@ -90,9 +90,9 @@ arena_stats_merge(tsdn_t *tsdn, arena_t *arena, unsigned *nthreads,
 	arena_basic_stats_merge(tsdn, arena, nthreads, dss, dirty_decay_ms,
 	    muzzy_decay_ms, nactive, ndirty, nmuzzy);
 
-	size_t base_allocated, base_resident, base_mapped, metadata_thp;
+	size_t base_allocated, base_resident, base_mapped;
 	base_stats_get(tsdn, arena->base, &base_allocated, &base_resident,
-	    &base_mapped, &metadata_thp);
+	    &base_mapped);
 
 	arena_stats_lock(tsdn, &arena->stats);
 
@@ -127,7 +127,6 @@ arena_stats_merge(tsdn_t *tsdn, arena_t *arena, unsigned *nthreads,
 
 	arena_stats_accum_zu(&astats->base, base_allocated);
 	arena_stats_accum_zu(&astats->internal, arena_internal_get(arena));
-	arena_stats_accum_zu(&astats->metadata_thp, metadata_thp);
 	arena_stats_accum_zu(&astats->resident, base_resident +
 	    (((atomic_load_zu(&arena->nactive, ATOMIC_RELAXED) +
 	    extents_npages_get(&arena->extents_dirty) +
diff --git a/src/base.c b/src/base.c
index f3c61661..421f295a 100644
--- a/src/base.c
+++ b/src/base.c
@@ -12,22 +12,8 @@
 
 static base_t *b0;
 
-metadata_thp_mode_t opt_metadata_thp = METADATA_THP_DEFAULT;
-
-const char *metadata_thp_mode_names[] = {
-	"disabled",
-	"auto",
-	"always"
-};
-
 /******************************************************************************/
 
-static inline bool
-metadata_thp_madvise(void) {
-	return (metadata_thp_enabled() &&
-	    (init_system_thp_mode == thp_mode_default));
-}
-
 static void *
 base_map(tsdn_t *tsdn, extent_hooks_t *extent_hooks, unsigned ind, size_t size) {
 	void *addr;
@@ -107,12 +93,7 @@ base_unmap(tsdn_t *tsdn, extent_hooks_t *extent_hooks, unsigned ind, void *addr,
 		post_reentrancy(tsd);
 	}
 label_done:
-	if (metadata_thp_madvise()) {
-		/* Set NOHUGEPAGE after unmap to avoid kernel defrag. */
-		assert(((uintptr_t)addr & HUGEPAGE_MASK) == 0 &&
-		    (size & HUGEPAGE_MASK) == 0);
-		pages_nohuge(addr, size);
-	}
+	return;
 }
 
 static void
@@ -140,42 +121,6 @@ base_get_num_blocks(base_t *base, bool with_new_block) {
 	return n_blocks;
 }
 
-static void
-base_auto_thp_switch(tsdn_t *tsdn, base_t *base) {
-	assert(opt_metadata_thp == metadata_thp_auto);
-	malloc_mutex_assert_owner(tsdn, &base->mtx);
-	if (base->auto_thp_switched) {
-		return;
-	}
-	/* Called when adding a new block. */
-	bool should_switch;
-	if (base_ind_get(base) != 0) {
-		should_switch = (base_get_num_blocks(base, true) ==
-		    BASE_AUTO_THP_THRESHOLD);
-	} else {
-		should_switch = (base_get_num_blocks(base, true) ==
-		    BASE_AUTO_THP_THRESHOLD_A0);
-	}
-	if (!should_switch) {
-		return;
-	}
-
-	base->auto_thp_switched = true;
-	assert(!config_stats || base->n_thp == 0);
-	/* Make the initial blocks THP lazily. */
-	base_block_t *block = base->blocks;
-	while (block != NULL) {
-		assert((block->size & HUGEPAGE_MASK) == 0);
-		pages_huge(block, block->size);
-		if (config_stats) {
-			base->n_thp += HUGEPAGE_CEILING(block->size -
-			    extent_bsize_get(&block->extent)) >> LG_HUGEPAGE;
-		}
-		block = block->next;
-		assert(block == NULL || (base_ind_get(base) == 0));
-	}
-}
-
 static void *
 base_extent_bump_alloc_helper(extent_t *extent, size_t *gap_size, size_t size,
     size_t alignment) {
@@ -218,13 +163,6 @@ base_extent_bump_alloc_post(base_t *base, extent_t *extent, size_t gap_size,
 		    PAGE_CEILING((uintptr_t)addr - gap_size);
 		assert(base->allocated <= base->resident);
 		assert(base->resident <= base->mapped);
-		if (metadata_thp_madvise() && (opt_metadata_thp ==
-		    metadata_thp_always || base->auto_thp_switched)) {
-			base->n_thp += (HUGEPAGE_CEILING((uintptr_t)addr + size)
-			    - HUGEPAGE_CEILING((uintptr_t)addr - gap_size)) >>
-			    LG_HUGEPAGE;
-			assert(base->mapped >= base->n_thp << LG_HUGEPAGE);
-		}
 	}
 }
 
@@ -273,24 +211,6 @@ base_block_alloc(tsdn_t *tsdn, base_t *base, extent_hooks_t *extent_hooks,
 		return NULL;
 	}
 
-	if (metadata_thp_madvise()) {
-		void *addr = (void *)block;
-		assert(((uintptr_t)addr & HUGEPAGE_MASK) == 0 &&
-		    (block_size & HUGEPAGE_MASK) == 0);
-		if (opt_metadata_thp == metadata_thp_always) {
-			pages_huge(addr, block_size);
-		} else if (opt_metadata_thp == metadata_thp_auto &&
-		    base != NULL) {
-			/* base != NULL indicates this is not a new base. */
-			malloc_mutex_lock(tsdn, &base->mtx);
-			base_auto_thp_switch(tsdn, base);
-			if (base->auto_thp_switched) {
-				pages_huge(addr, block_size);
-			}
-			malloc_mutex_unlock(tsdn, &base->mtx);
-		}
-	}
-
 	*pind_last = sz_psz2ind(block_size);
 	block->size = block_size;
 	block->next = NULL;
@@ -327,16 +247,8 @@ base_extent_alloc(tsdn_t *tsdn, base_t *base, size_t size, size_t alignment) {
 		base->allocated += sizeof(base_block_t);
 		base->resident += PAGE_CEILING(sizeof(base_block_t));
 		base->mapped += block->size;
-		if (metadata_thp_madvise() &&
-		    !(opt_metadata_thp == metadata_thp_auto
-		      && !base->auto_thp_switched)) {
-			assert(base->n_thp > 0);
-			base->n_thp += HUGEPAGE_CEILING(sizeof(base_block_t)) >>
-			    LG_HUGEPAGE;
-		}
 		assert(base->allocated <= base->resident);
 		assert(base->resident <= base->mapped);
-		assert(base->n_thp << LG_HUGEPAGE <= base->mapped);
 	}
 	return &block->extent;
 }
@@ -371,7 +283,6 @@ base_new(tsdn_t *tsdn, unsigned ind, extent_hooks_t *extent_hooks) {
 	base->pind_last = pind_last;
 	base->extent_sn_next = extent_sn_next;
 	base->blocks = block;
-	base->auto_thp_switched = false;
 	for (szind_t i = 0; i < SC_NSIZES; i++) {
 		extent_heap_new(&base->avail[i]);
 	}
@@ -379,12 +290,8 @@ base_new(tsdn_t *tsdn, unsigned ind, extent_hooks_t *extent_hooks) {
 		base->allocated = sizeof(base_block_t);
 		base->resident = PAGE_CEILING(sizeof(base_block_t));
 		base->mapped = block->size;
-		base->n_thp = (opt_metadata_thp == metadata_thp_always) &&
-		    metadata_thp_madvise() ? HUGEPAGE_CEILING(sizeof(base_block_t))
-		    >> LG_HUGEPAGE : 0;
 		assert(base->allocated <= base->resident);
 		assert(base->resident <= base->mapped);
-		assert(base->n_thp << LG_HUGEPAGE <= base->mapped);
 	}
 	base_extent_bump_alloc_post(base, &block->extent, gap_size, base,
 	    base_size);
@@ -479,7 +386,7 @@ base_alloc_extent(tsdn_t *tsdn, base_t *base) {
 
 void
 base_stats_get(tsdn_t *tsdn, base_t *base, size_t *allocated, size_t *resident,
-    size_t *mapped, size_t *n_thp) {
+    size_t *mapped) {
 	cassert(config_stats);
 
 	malloc_mutex_lock(tsdn, &base->mtx);
@@ -488,7 +395,6 @@ base_stats_get(tsdn_t *tsdn, base_t *base, size_t *allocated, size_t *resident,
 	*allocated = base->allocated;
 	*resident = base->resident;
 	*mapped = base->mapped;
-	*n_thp = base->n_thp;
 	malloc_mutex_unlock(tsdn, &base->mtx);
 }
 
diff --git a/src/ctl.c b/src/ctl.c
index 48afaa61..05ed617c 100644
--- a/src/ctl.c
+++ b/src/ctl.c
@@ -82,7 +82,6 @@ CTL_PROTO(config_xmalloc)
 CTL_PROTO(opt_abort)
 CTL_PROTO(opt_abort_conf)
 CTL_PROTO(opt_confirm_conf)
-CTL_PROTO(opt_metadata_thp)
 CTL_PROTO(opt_retain)
 CTL_PROTO(opt_dss)
 CTL_PROTO(opt_narenas)
@@ -99,7 +98,6 @@ CTL_PROTO(opt_zero)
 CTL_PROTO(opt_utrace)
 CTL_PROTO(opt_xmalloc)
 CTL_PROTO(opt_tcache)
-CTL_PROTO(opt_thp)
 CTL_PROTO(opt_lg_extent_max_active_fit)
 CTL_PROTO(opt_lg_tcache_max)
 CTL_PROTO(opt_prof)
@@ -207,7 +205,6 @@ CTL_PROTO(stats_arenas_i_muzzy_nmadvise)
 CTL_PROTO(stats_arenas_i_muzzy_purged)
 CTL_PROTO(stats_arenas_i_base)
 CTL_PROTO(stats_arenas_i_internal)
-CTL_PROTO(stats_arenas_i_metadata_thp)
 CTL_PROTO(stats_arenas_i_tcache_bytes)
 CTL_PROTO(stats_arenas_i_resident)
 CTL_PROTO(stats_arenas_i_abandoned_vm)
@@ -218,7 +215,6 @@ CTL_PROTO(stats_background_thread_num_threads)
 CTL_PROTO(stats_background_thread_num_runs)
 CTL_PROTO(stats_background_thread_run_interval)
 CTL_PROTO(stats_metadata)
-CTL_PROTO(stats_metadata_thp)
 CTL_PROTO(stats_resident)
 CTL_PROTO(stats_mapped)
 CTL_PROTO(stats_retained)
@@ -309,7 +305,6 @@ static const ctl_named_node_t opt_node[] = {
 	{NAME("abort"),		CTL(opt_abort)},
 	{NAME("abort_conf"),	CTL(opt_abort_conf)},
 	{NAME("confirm_conf"),	CTL(opt_confirm_conf)},
-	{NAME("metadata_thp"),	CTL(opt_metadata_thp)},
 	{NAME("retain"),	CTL(opt_retain)},
 	{NAME("dss"),		CTL(opt_dss)},
 	{NAME("narenas"),	CTL(opt_narenas)},
@@ -326,7 +321,6 @@ static const ctl_named_node_t opt_node[] = {
 	{NAME("utrace"),	CTL(opt_utrace)},
 	{NAME("xmalloc"),	CTL(opt_xmalloc)},
 	{NAME("tcache"),	CTL(opt_tcache)},
-	{NAME("thp"),		CTL(opt_thp)},
 	{NAME("lg_extent_max_active_fit"), CTL(opt_lg_extent_max_active_fit)},
 	{NAME("lg_tcache_max"),	CTL(opt_lg_tcache_max)},
 	{NAME("prof"),		CTL(opt_prof)},
@@ -541,7 +535,6 @@ static const ctl_named_node_t stats_arenas_i_node[] = {
 	{NAME("muzzy_purged"),	CTL(stats_arenas_i_muzzy_purged)},
 	{NAME("base"),		CTL(stats_arenas_i_base)},
 	{NAME("internal"),	CTL(stats_arenas_i_internal)},
-	{NAME("metadata_thp"),	CTL(stats_arenas_i_metadata_thp)},
 	{NAME("tcache_bytes"),	CTL(stats_arenas_i_tcache_bytes)},
 	{NAME("resident"),	CTL(stats_arenas_i_resident)},
 	{NAME("abandoned_vm"),	CTL(stats_arenas_i_abandoned_vm)},
@@ -582,7 +575,6 @@ static const ctl_named_node_t stats_node[] = {
 	{NAME("allocated"),	CTL(stats_allocated)},
 	{NAME("active"),	CTL(stats_active)},
 	{NAME("metadata"),	CTL(stats_metadata)},
-	{NAME("metadata_thp"),	CTL(stats_metadata_thp)},
 	{NAME("resident"),	CTL(stats_resident)},
 	{NAME("mapped"),	CTL(stats_mapped)},
 	{NAME("retained"),	CTL(stats_retained)},
@@ -884,8 +876,6 @@ MUTEX_PROF_ARENA_MUTEXES
 			    &astats->astats.internal);
 			accum_atomic_zu(&sdstats->astats.resident,
 			    &astats->astats.resident);
-			accum_atomic_zu(&sdstats->astats.metadata_thp,
-			    &astats->astats.metadata_thp);
 		} else {
 			assert(atomic_load_zu(
 			    &astats->astats.internal, ATOMIC_RELAXED) == 0);
@@ -1076,8 +1066,6 @@ ctl_refresh(tsdn_t *tsdn) {
 		    &ctl_sarena->astats->astats.base, ATOMIC_RELAXED) +
 		    atomic_load_zu(&ctl_sarena->astats->astats.internal,
 			ATOMIC_RELAXED);
-		ctl_stats->metadata_thp = atomic_load_zu(
-		    &ctl_sarena->astats->astats.metadata_thp, ATOMIC_RELAXED);
 		ctl_stats->resident = atomic_load_zu(
 		    &ctl_sarena->astats->astats.resident, ATOMIC_RELAXED);
 		ctl_stats->mapped = atomic_load_zu(
@@ -1762,8 +1750,6 @@ CTL_RO_CONFIG_GEN(config_xmalloc, bool)
 CTL_RO_NL_GEN(opt_abort, opt_abort, bool)
 CTL_RO_NL_GEN(opt_abort_conf, opt_abort_conf, bool)
 CTL_RO_NL_GEN(opt_confirm_conf, opt_confirm_conf, bool)
-CTL_RO_NL_GEN(opt_metadata_thp, metadata_thp_mode_names[opt_metadata_thp],
-    const char *)
 CTL_RO_NL_GEN(opt_retain, opt_retain, bool)
 CTL_RO_NL_GEN(opt_dss, opt_dss, const char *)
 CTL_RO_NL_GEN(opt_narenas, opt_narenas, unsigned)
@@ -1781,7 +1767,6 @@ CTL_RO_NL_CGEN(config_fill, opt_zero, opt_zero, bool)
 CTL_RO_NL_CGEN(config_utrace, opt_utrace, opt_utrace, bool)
 CTL_RO_NL_CGEN(config_xmalloc, opt_xmalloc, opt_xmalloc, bool)
 CTL_RO_NL_GEN(opt_tcache, opt_tcache, bool)
-CTL_RO_NL_GEN(opt_thp, thp_mode_names[opt_thp], const char *)
 CTL_RO_NL_GEN(opt_lg_extent_max_active_fit, opt_lg_extent_max_active_fit,
     size_t)
 CTL_RO_NL_GEN(opt_lg_tcache_max, opt_lg_tcache_max, ssize_t)
@@ -2806,7 +2791,6 @@ prof_log_stop_ctl(tsd_t *tsd, const size_t *mib, size_t miblen, void *oldp,
 CTL_RO_CGEN(config_stats, stats_allocated, ctl_stats->allocated, size_t)
 CTL_RO_CGEN(config_stats, stats_active, ctl_stats->active, size_t)
 CTL_RO_CGEN(config_stats, stats_metadata, ctl_stats->metadata, size_t)
-CTL_RO_CGEN(config_stats, stats_metadata_thp, ctl_stats->metadata_thp, size_t)
 CTL_RO_CGEN(config_stats, stats_resident, ctl_stats->resident, size_t)
 CTL_RO_CGEN(config_stats, stats_mapped, ctl_stats->mapped, size_t)
 CTL_RO_CGEN(config_stats, stats_retained, ctl_stats->retained, size_t)
@@ -2866,9 +2850,6 @@ CTL_RO_CGEN(config_stats, stats_arenas_i_base,
 CTL_RO_CGEN(config_stats, stats_arenas_i_internal,
     atomic_load_zu(&arenas_i(mib[2])->astats->astats.internal, ATOMIC_RELAXED),
     size_t)
-CTL_RO_CGEN(config_stats, stats_arenas_i_metadata_thp,
-    atomic_load_zu(&arenas_i(mib[2])->astats->astats.metadata_thp,
-    ATOMIC_RELAXED), size_t)
 CTL_RO_CGEN(config_stats, stats_arenas_i_tcache_bytes,
     atomic_load_zu(&arenas_i(mib[2])->astats->astats.tcache_bytes,
     ATOMIC_RELAXED), size_t)
diff --git a/src/extent.c b/src/extent.c
index 9237f903..9cbeb400 100644
--- a/src/extent.c
+++ b/src/extent.c
@@ -1116,8 +1116,7 @@ extent_need_manual_zero(arena_t *arena) {
 	 * default extent hooks installed (in which case the purge semantics may
 	 * change); or 2) transparent huge pages enabled.
 	 */
-	return (!arena_has_default_hooks(arena) ||
-		(opt_thp == thp_mode_always));
+	return !arena_has_default_hooks(arena);
 }
 
 /*
@@ -1241,9 +1240,6 @@ extent_alloc_default_impl(tsdn_t *tsdn, arena_t *arena, void *new_addr,
 	void *ret = extent_alloc_core(tsdn, arena, new_addr, size, alignment, zero,
 	    commit, (dss_prec_t)atomic_load_u(&arena->dss_prec,
 	    ATOMIC_RELAXED));
-	if (have_madvise_huge && ret) {
-		pages_set_thp_state(ret, size);
-	}
 	return ret;
 }
 
diff --git a/src/jemalloc.c b/src/jemalloc.c
index cc916497..4c94568d 100644
--- a/src/jemalloc.c
+++ b/src/jemalloc.c
@@ -1172,23 +1172,6 @@ malloc_conf_init_helper(sc_data_t *sc_data, unsigned bin_shard_sizes[SC_NBINS],
 
 			CONF_HANDLE_BOOL(opt_abort, "abort")
 			CONF_HANDLE_BOOL(opt_abort_conf, "abort_conf")
-			if (strncmp("metadata_thp", k, klen) == 0) {
-				int i;
-				bool match = false;
-				for (i = 0; i < metadata_thp_mode_limit; i++) {
-					if (strncmp(metadata_thp_mode_names[i],
-					    v, vlen) == 0) {
-						opt_metadata_thp = i;
-						match = true;
-						break;
-					}
-				}
-				if (!match) {
-					CONF_ERROR("Invalid conf value",
-					    k, klen, v, vlen);
-				}
-				CONF_CONTINUE;
-			}
 			CONF_HANDLE_BOOL(opt_retain, "retain")
 			if (strncmp("dss", k, klen) == 0) {
 				int i;
@@ -1388,27 +1371,6 @@ malloc_conf_init_helper(sc_data_t *sc_data, unsigned bin_shard_sizes[SC_NBINS],
 					CONF_CONTINUE;
 				}
 			}
-			if (CONF_MATCH("thp")) {
-				bool match = false;
-				for (int i = 0; i < thp_mode_names_limit; i++) {
-					if (strncmp(thp_mode_names[i],v, vlen)
-					    == 0) {
-						if (!have_madvise_huge) {
-							CONF_ERROR(
-							    "No THP support",
-							    k, klen, v, vlen);
-						}
-						opt_thp = i;
-						match = true;
-						break;
-					}
-				}
-				if (!match) {
-					CONF_ERROR("Invalid conf value",
-					    k, klen, v, vlen);
-				}
-				CONF_CONTINUE;
-			}
 			CONF_ERROR("Invalid conf pair", k, klen, v, vlen);
 #undef CONF_ERROR
 #undef CONF_CONTINUE
diff --git a/src/pages.c b/src/pages.c
index 2125d17f..555c359c 100644
--- a/src/pages.c
+++ b/src/pages.c
@@ -35,15 +35,6 @@ static int	mmap_flags;
 #endif
 static bool	os_overcommits;
 
-const char *thp_mode_names[] = {
-	"default",
-	"always",
-	"never",
-	"not supported"
-};
-thp_mode_t opt_thp = THP_MODE_DEFAULT;
-thp_mode_t init_system_thp_mode;
-
 /* Runtime support for lazy purge. Irrelevant when !pages_can_purge_lazy. */
 static bool pages_can_purge_lazy_runtime = true;
 
@@ -540,75 +531,6 @@ os_overcommits_proc(void) {
 }
 #endif
 
-void
-pages_set_thp_state (void *ptr, size_t size) {
-	if (opt_thp == thp_mode_default || opt_thp == init_system_thp_mode) {
-		return;
-	}
-	assert(opt_thp != thp_mode_not_supported &&
-	    init_system_thp_mode != thp_mode_not_supported);
-
-	if (opt_thp == thp_mode_always
-	    && init_system_thp_mode != thp_mode_never) {
-		assert(init_system_thp_mode == thp_mode_default);
-		pages_huge_unaligned(ptr, size);
-	} else if (opt_thp == thp_mode_never) {
-		assert(init_system_thp_mode == thp_mode_default ||
-		    init_system_thp_mode == thp_mode_always);
-		pages_nohuge_unaligned(ptr, size);
-	}
-}
-
-static void
-init_thp_state(void) {
-	if (!have_madvise_huge) {
-		if (metadata_thp_enabled() && opt_abort) {
-			malloc_write("<jemalloc>: no MADV_HUGEPAGE support\n");
-			abort();
-		}
-		goto label_error;
-	}
-
-	static const char sys_state_madvise[] = "always [madvise] never\n";
-	static const char sys_state_always[] = "[always] madvise never\n";
-	static const char sys_state_never[] = "always madvise [never]\n";
-	char buf[sizeof(sys_state_madvise)];
-
-#if defined(JEMALLOC_USE_SYSCALL) && defined(SYS_open)
-	int fd = (int)syscall(SYS_open,
-	    "/sys/kernel/mm/transparent_hugepage/enabled", O_RDONLY);
-#else
-	int fd = open("/sys/kernel/mm/transparent_hugepage/enabled", O_RDONLY);
-#endif
-	if (fd == -1) {
-		goto label_error;
-	}
-
-	ssize_t nread = malloc_read_fd(fd, &buf, sizeof(buf));
-#if defined(JEMALLOC_USE_SYSCALL) && defined(SYS_close)
-	syscall(SYS_close, fd);
-#else
-	close(fd);
-#endif
-
-        if (nread < 0) {
-		goto label_error; 
-        }
-
-	if (strncmp(buf, sys_state_madvise, (size_t)nread) == 0) {
-		init_system_thp_mode = thp_mode_default;
-	} else if (strncmp(buf, sys_state_always, (size_t)nread) == 0) {
-		init_system_thp_mode = thp_mode_always;
-	} else if (strncmp(buf, sys_state_never, (size_t)nread) == 0) {
-		init_system_thp_mode = thp_mode_never;
-	} else {
-		goto label_error;
-	}
-	return;
-label_error:
-	opt_thp = init_system_thp_mode = thp_mode_not_supported;
-}
-
 bool
 pages_boot(void) {
 	os_page = os_page_detect();
@@ -644,8 +566,6 @@ pages_boot(void) {
 
 #endif  /* __ANDROID__ */
 
-	init_thp_state();
-
 #ifdef __FreeBSD__
 	/*
 	 * FreeBSD doesn't need the check; madvise(2) is known to work.
diff --git a/src/stats.c b/src/stats.c
index 118e05d2..bfe02a49 100644
--- a/src/stats.c
+++ b/src/stats.c
@@ -664,7 +664,7 @@ stats_arena_print(emitter_t *emitter, unsigned i, bool bins, bool large,
 	const char *dss;
 	ssize_t dirty_decay_ms, muzzy_decay_ms;
 	size_t page, pactive, pdirty, pmuzzy, mapped, retained;
-	size_t base, internal, resident, metadata_thp, extent_avail;
+	size_t base, internal, resident, extent_avail;
 	uint64_t dirty_npurge, dirty_nmadvise, dirty_purged;
 	uint64_t muzzy_npurge, muzzy_nmadvise, muzzy_purged;
 	size_t small_allocated;
@@ -960,7 +960,6 @@ stats_arena_print(emitter_t *emitter, unsigned i, bool bins, bool large,
 	GET_AND_EMIT_MEM_STAT(retained)
 	GET_AND_EMIT_MEM_STAT(base)
 	GET_AND_EMIT_MEM_STAT(internal)
-	GET_AND_EMIT_MEM_STAT(metadata_thp)
 	GET_AND_EMIT_MEM_STAT(tcache_bytes)
 	GET_AND_EMIT_MEM_STAT(resident)
 	GET_AND_EMIT_MEM_STAT(abandoned_vm)
@@ -1072,7 +1071,6 @@ stats_general_print(emitter_t *emitter) {
 	OPT_WRITE_UNSIGNED("narenas")
 	OPT_WRITE_CHAR_P("percpu_arena")
 	OPT_WRITE_SIZE_T("oversize_threshold")
-	OPT_WRITE_CHAR_P("metadata_thp")
 	OPT_WRITE_BOOL_MUTABLE("background_thread", "background_thread")
 	OPT_WRITE_SSIZE_T_MUTABLE("dirty_decay_ms", "arenas.dirty_decay_ms")
 	OPT_WRITE_SSIZE_T_MUTABLE("muzzy_decay_ms", "arenas.muzzy_decay_ms")
@@ -1083,7 +1081,6 @@ stats_general_print(emitter_t *emitter) {
 	OPT_WRITE_BOOL("xmalloc")
 	OPT_WRITE_BOOL("tcache")
 	OPT_WRITE_SSIZE_T("lg_tcache_max")
-	OPT_WRITE_CHAR_P("thp")
 	OPT_WRITE_BOOL("prof")
 	OPT_WRITE_CHAR_P("prof_prefix")
 	OPT_WRITE_BOOL_MUTABLE("prof_active", "prof.active")
@@ -1236,7 +1233,7 @@ stats_print_helper(emitter_t *emitter, bool merged, bool destroyed,
 	 * These should be deleted.  We keep them around for a while, to aid in
 	 * the transition to the emitter code.
 	 */
-	size_t allocated, active, metadata, metadata_thp, resident, mapped,
+	size_t allocated, active, metadata, resident, mapped,
 	    retained;
 	size_t num_background_threads;
 	uint64_t background_thread_num_runs, background_thread_run_interval;
@@ -1244,7 +1241,6 @@ stats_print_helper(emitter_t *emitter, bool merged, bool destroyed,
 	CTL_GET("stats.allocated", &allocated, size_t);
 	CTL_GET("stats.active", &active, size_t);
 	CTL_GET("stats.metadata", &metadata, size_t);
-	CTL_GET("stats.metadata_thp", &metadata_thp, size_t);
 	CTL_GET("stats.resident", &resident, size_t);
 	CTL_GET("stats.mapped", &mapped, size_t);
 	CTL_GET("stats.retained", &retained, size_t);
@@ -1267,15 +1263,13 @@ stats_print_helper(emitter_t *emitter, bool merged, bool destroyed,
 	emitter_json_kv(emitter, "allocated", emitter_type_size, &allocated);
 	emitter_json_kv(emitter, "active", emitter_type_size, &active);
 	emitter_json_kv(emitter, "metadata", emitter_type_size, &metadata);
-	emitter_json_kv(emitter, "metadata_thp", emitter_type_size,
-	    &metadata_thp);
 	emitter_json_kv(emitter, "resident", emitter_type_size, &resident);
 	emitter_json_kv(emitter, "mapped", emitter_type_size, &mapped);
 	emitter_json_kv(emitter, "retained", emitter_type_size, &retained);
 
 	emitter_table_printf(emitter, "Allocated: %zu, active: %zu, "
-	    "metadata: %zu (n_thp %zu), resident: %zu, mapped: %zu, "
-	    "retained: %zu\n", allocated, active, metadata, metadata_thp,
+	    "metadata: %zu, resident: %zu, mapped: %zu, "
+	    "retained: %zu\n", allocated, active, metadata,
 	    resident, mapped, retained);
 
 	/* Background thread stats. */
diff --git a/test/unit/base.c b/test/unit/base.c
index 6b792cf2..7fa24ac0 100644
--- a/test/unit/base.c
+++ b/test/unit/base.c
@@ -28,28 +28,22 @@ static extent_hooks_t hooks_not_null = {
 
 TEST_BEGIN(test_base_hooks_default) {
 	base_t *base;
-	size_t allocated0, allocated1, resident, mapped, n_thp;
+	size_t allocated0, allocated1, resident, mapped;
 
 	tsdn_t *tsdn = tsd_tsdn(tsd_fetch());
 	base = base_new(tsdn, 0, (extent_hooks_t *)&extent_hooks_default);
 
 	if (config_stats) {
-		base_stats_get(tsdn, base, &allocated0, &resident, &mapped,
-		    &n_thp);
+		base_stats_get(tsdn, base, &allocated0, &resident, &mapped);
 		assert_zu_ge(allocated0, sizeof(base_t),
 		    "Base header should count as allocated");
-		if (opt_metadata_thp == metadata_thp_always) {
-			assert_zu_gt(n_thp, 0,
-			    "Base should have 1 THP at least.");
-		}
 	}
 
 	assert_ptr_not_null(base_alloc(tsdn, base, 42, 1),
 	    "Unexpected base_alloc() failure");
 
 	if (config_stats) {
-		base_stats_get(tsdn, base, &allocated1, &resident, &mapped,
-		    &n_thp);
+		base_stats_get(tsdn, base, &allocated1, &resident, &mapped);
 		assert_zu_ge(allocated1 - allocated0, 42,
 		    "At least 42 bytes were allocated by base_alloc()");
 	}
@@ -61,7 +55,7 @@ TEST_END
 TEST_BEGIN(test_base_hooks_null) {
 	extent_hooks_t hooks_orig;
 	base_t *base;
-	size_t allocated0, allocated1, resident, mapped, n_thp;
+	size_t allocated0, allocated1, resident, mapped;
 
 	extent_hooks_prep();
 	try_dalloc = false;
@@ -77,22 +71,16 @@ TEST_BEGIN(test_base_hooks_null) {
 	assert_ptr_not_null(base, "Unexpected base_new() failure");
 
 	if (config_stats) {
-		base_stats_get(tsdn, base, &allocated0, &resident, &mapped,
-		    &n_thp);
+		base_stats_get(tsdn, base, &allocated0, &resident, &mapped);
 		assert_zu_ge(allocated0, sizeof(base_t),
 		    "Base header should count as allocated");
-		if (opt_metadata_thp == metadata_thp_always) {
-			assert_zu_gt(n_thp, 0,
-			    "Base should have 1 THP at least.");
-		}
 	}
 
 	assert_ptr_not_null(base_alloc(tsdn, base, 42, 1),
 	    "Unexpected base_alloc() failure");
 
 	if (config_stats) {
-		base_stats_get(tsdn, base, &allocated1, &resident, &mapped,
-		    &n_thp);
+		base_stats_get(tsdn, base, &allocated1, &resident, &mapped);
 		assert_zu_ge(allocated1 - allocated0, 42,
 		    "At least 42 bytes were allocated by base_alloc()");
 	}
diff --git a/test/unit/mallctl.c b/test/unit/mallctl.c
index 3a75ac04..64572cc9 100644
--- a/test/unit/mallctl.c
+++ b/test/unit/mallctl.c
@@ -160,7 +160,6 @@ TEST_BEGIN(test_mallctl_opt) {
 	TEST_MALLCTL_OPT(bool, abort, always);
 	TEST_MALLCTL_OPT(bool, abort_conf, always);
 	TEST_MALLCTL_OPT(bool, confirm_conf, always);
-	TEST_MALLCTL_OPT(const char *, metadata_thp, always);
 	TEST_MALLCTL_OPT(bool, retain, always);
 	TEST_MALLCTL_OPT(const char *, dss, always);
 	TEST_MALLCTL_OPT(unsigned, narenas, always);
@@ -177,7 +176,6 @@ TEST_BEGIN(test_mallctl_opt) {
 	TEST_MALLCTL_OPT(bool, tcache, always);
 	TEST_MALLCTL_OPT(size_t, lg_extent_max_active_fit, always);
 	TEST_MALLCTL_OPT(size_t, lg_tcache_max, always);
-	TEST_MALLCTL_OPT(const char *, thp, always);
 	TEST_MALLCTL_OPT(bool, prof, prof);
 	TEST_MALLCTL_OPT(const char *, prof_prefix, prof);
 	TEST_MALLCTL_OPT(bool, prof_active, prof);
diff --git a/test/unit/pages.c b/test/unit/pages.c
deleted file mode 100644
index ee729eec..00000000
--- a/test/unit/pages.c
+++ /dev/null
@@ -1,29 +0,0 @@
-#include "test/jemalloc_test.h"
-
-TEST_BEGIN(test_pages_huge) {
-	size_t alloc_size;
-	bool commit;
-	void *pages, *hugepage;
-
-	alloc_size = HUGEPAGE * 2 - PAGE;
-	commit = true;
-	pages = pages_map(NULL, alloc_size, PAGE, &commit);
-	assert_ptr_not_null(pages, "Unexpected pages_map() error");
-
-	if (init_system_thp_mode == thp_mode_default) {
-	    hugepage = (void *)(ALIGNMENT_CEILING((uintptr_t)pages, HUGEPAGE));
-	    assert_b_ne(pages_huge(hugepage, HUGEPAGE), have_madvise_huge,
-	        "Unexpected pages_huge() result");
-	    assert_false(pages_nohuge(hugepage, HUGEPAGE),
-	        "Unexpected pages_nohuge() result");
-	}
-
-	pages_unmap(pages, alloc_size);
-}
-TEST_END
-
-int
-main(void) {
-	return test(
-	    test_pages_huge);
-}