This backports https://github.com/jemalloc/jemalloc/pull/2312, which
I opened after discussion with upstream in
https://github.com/jemalloc/jemalloc/issues/2305, where they explicitly
clarify that the HPA feature is not tested, not supported, and not
intended for use on non-x86 platforms.

From: matoro <matoro@users.noreply.github.com>
Date: Wed, 27 Jul 2022 11:13:35 -0400
Subject: [PATCH] Support HPA only on x86

This can be overridden with -DHPA_SUPPORTED.

Unfortunately has to be implemented using preprocessor macros, can't use
test_skip_if because the test name string is already corrupted by that
time.  See https://github.com/jemalloc/jemalloc/issues/2305
---
 include/jemalloc/internal/hpa.h | 27 +++++++++++++++++++++++++++
 src/hpa.c                       |  7 +------
 test/include/test/test.h        |  9 +++++++++
 test/unit/psset.c               | 14 ++++++++++++++
 4 files changed, 51 insertions(+), 6 deletions(-)

diff --git a/include/jemalloc/internal/hpa.h b/include/jemalloc/internal/hpa.h
index f3562853e..3d389a644 100644
--- a/include/jemalloc/internal/hpa.h
+++ b/include/jemalloc/internal/hpa.h
@@ -7,6 +7,33 @@
 #include "jemalloc/internal/pai.h"
 #include "jemalloc/internal/psset.h"
 
+/*
+ * The HPA_SUPPORTED macro is not a technical indicator of whether HPA
+ * theoretically functions on the platform, but rather whether the platform is
+ * tested/supported for using HPA on by the jemalloc developers.
+ */
+#ifdef HPA_SUPPORTED
+#warning "Force-enabling HPA support. Do NOT report issues to jemalloc developers."
+#else
+#define HPA_SUPPORTED 1
+
+/*
+ * At least until the API and implementation is somewhat settled, we
+ * don't want to try to debug the VM subsystem on the hardest-to-test
+ * platform.
+ */
+#ifdef _WIN32
+#undef HPA_SUPPORTED
+#endif
+
+/*
+ * https://github.com/jemalloc/jemalloc/issues/2305#issuecomment-1195917164
+ */
+#if !defined(__x86_64__) && !defined(__i386__)
+#undef HPA_SUPPORTED
+#endif
+#endif
+
 typedef struct hpa_central_s hpa_central_t;
 struct hpa_central_s {
 	/*
diff --git a/src/hpa.c b/src/hpa.c
index 7e2aeba0c..0a9946b9e 100644
--- a/src/hpa.c
+++ b/src/hpa.c
@@ -25,12 +25,7 @@ static uint64_t hpa_time_until_deferred_work(tsdn_t *tsdn, pai_t *self);
 
 bool
 hpa_supported() {
-#ifdef _WIN32
-	/*
-	 * At least until the API and implementation is somewhat settled, we
-	 * don't want to try to debug the VM subsystem on the hardest-to-test
-	 * platform.
-	 */
+#ifndef HPA_SUPPORTED
 	return false;
 #endif
 	if (!pages_can_hugify) {
diff --git a/test/include/test/test.h b/test/include/test/test.h
index d4b65912d..7fa56f7be 100644
--- a/test/include/test/test.h
+++ b/test/include/test/test.h
@@ -546,6 +546,15 @@ static void								\
 f(void) {								\
 	p_test_init(#f);
 
+#define TEST_SKIP(f)							\
+static void									\
+f(void) {									\
+	p_test_init(#f);						\
+	test_skip("%s:%s:%d: Test skipped: ",	\
+		__func__, __FILE__, __LINE__);		\
+	p_test_fini();							\
+}
+
 #define TEST_END							\
 	goto label_test_end;						\
 label_test_end:								\
diff --git a/test/unit/psset.c b/test/unit/psset.c
index 6ff720129..af764d3a3 100644
--- a/test/unit/psset.c
+++ b/test/unit/psset.c
@@ -276,6 +276,7 @@ TEST_BEGIN(test_evict) {
 }
 TEST_END
 
+#ifdef HPA_SUPPORTED
 TEST_BEGIN(test_multi_pageslab) {
 	bool err;
 	hpdata_t *ps;
@@ -338,6 +339,9 @@ TEST_BEGIN(test_multi_pageslab) {
 	expect_false(err, "Allocation should have succeeded");
 }
 TEST_END
+#else
+TEST_SKIP(test_multi_pageslab)
+#endif
 
 static void
 stats_expect_empty(psset_bin_stats_t *stats) {
@@ -427,6 +431,7 @@ TEST_END
  * (There's nothing magic about these numbers; it's just useful to share the
  * setup between the oldest fit and the insert/remove test).
  */
+#ifdef HPA_SUPPORTED
 static void
 init_test_pageslabs(psset_t *psset, hpdata_t *pageslab,
     hpdata_t *worse_pageslab, edata_t *alloc, edata_t *worse_alloc) {
@@ -472,7 +477,9 @@ init_test_pageslabs(psset_t *psset, hpdata_t *pageslab,
 	    &alloc[HUGEPAGE_PAGES - 1]);
 	expect_ptr_null(evicted, "Unexpected eviction");
 }
+#endif
 
+#ifdef HPA_SUPPORTED
 TEST_BEGIN(test_oldest_fit) {
 	bool err;
 	edata_t alloc[HUGEPAGE_PAGES];
@@ -495,7 +502,11 @@ TEST_BEGIN(test_oldest_fit) {
 	    "Allocated from the wrong pageslab");
 }
 TEST_END
+#else
+TEST_SKIP(test_oldest_fit)
+#endif
 
+#ifdef HPA_SUPPORTED
 TEST_BEGIN(test_insert_remove) {
 	bool err;
 	hpdata_t *ps;
@@ -541,6 +552,9 @@ TEST_BEGIN(test_insert_remove) {
 	expect_true(err, "psset should be empty, but an alloc succeeded");
 }
 TEST_END
+#else
+TEST_SKIP(test_insert_remove)
+#endif
 
 TEST_BEGIN(test_purge_prefers_nonhuge) {
 	/*