From 7638093c7349065c52f2e607a15148876d81b4e3 Mon Sep 17 00:00:00 2001
From: Slobodan Predolac <spredolac@fb.com>
Date: Thu, 30 Apr 2026 13:27:40 -0700
Subject: [PATCH] Improve const correctness in the repo

---
 include/jemalloc/internal/arena_externs.h     | 14 ++---
 include/jemalloc/internal/arena_inlines_a.h   |  2 +-
 include/jemalloc/internal/bin_inlines.h       |  8 +--
 include/jemalloc/internal/bitmap.h            |  4 +-
 include/jemalloc/internal/div.h               |  2 +-
 include/jemalloc/internal/ecache.h            |  8 +--
 include/jemalloc/internal/edata.h             |  2 +-
 include/jemalloc/internal/ehooks.h            | 12 ++--
 include/jemalloc/internal/eset.h              |  6 +-
 include/jemalloc/internal/extent.h            |  2 +-
 include/jemalloc/internal/fb.h                | 56 ++++++++++---------
 include/jemalloc/internal/hpdata.h            |  8 +--
 .../internal/jemalloc_internal_inlines_b.h    |  2 +-
 include/jemalloc/internal/pa.h                | 10 ++--
 include/jemalloc/internal/pac.h               |  4 +-
 include/jemalloc/internal/psset.h             |  6 +-
 include/jemalloc/internal/tcache_inlines.h    |  4 +-
 src/arena.c                                   | 18 +++---
 src/base.c                                    |  6 +-
 src/eset.c                                    |  6 +-
 src/pa_extra.c                                |  8 +--
 21 files changed, 98 insertions(+), 90 deletions(-)

diff --git a/include/jemalloc/internal/arena_externs.h b/include/jemalloc/internal/arena_externs.h
index c5b6e6c7..6ee8a727 100644
--- a/include/jemalloc/internal/arena_externs.h
+++ b/include/jemalloc/internal/arena_externs.h
@@ -51,11 +51,11 @@ void arena_handle_deferred_work(tsdn_t *tsdn, arena_t *arena);
 edata_t *arena_extent_alloc_large(
     tsdn_t *tsdn, arena_t *arena, size_t usize, size_t alignment, bool zero);
 void arena_extent_dalloc_large_prep(
-    tsdn_t *tsdn, arena_t *arena, edata_t *edata);
+    tsdn_t *tsdn, arena_t *arena, const edata_t *edata);
 void arena_extent_ralloc_large_shrink(
-    tsdn_t *tsdn, arena_t *arena, edata_t *edata, size_t oldusize);
+    tsdn_t *tsdn, arena_t *arena, const edata_t *edata, size_t oldusize);
 void arena_extent_ralloc_large_expand(
-    tsdn_t *tsdn, arena_t *arena, edata_t *edata, size_t oldusize);
+    tsdn_t *tsdn, arena_t *arena, const edata_t *edata, size_t oldusize);
 bool arena_decay_ms_set(
     tsdn_t *tsdn, arena_t *arena, extent_state_t state, ssize_t decay_ms);
 ssize_t arena_decay_ms_get(arena_t *arena, extent_state_t state);
@@ -88,12 +88,12 @@ bool  arena_ralloc_no_move(tsdn_t *tsdn, void *ptr, size_t oldsize, size_t size,
 void *arena_ralloc(tsdn_t *tsdn, arena_t *arena, void *ptr, size_t oldsize,
     size_t size, size_t alignment, bool zero, bool slab, tcache_t *tcache,
     hook_ralloc_args_t *hook_args);
-dss_prec_t      arena_dss_prec_get(arena_t *arena);
-ehooks_t       *arena_get_ehooks(arena_t *arena);
+dss_prec_t      arena_dss_prec_get(const arena_t *arena);
+ehooks_t       *arena_get_ehooks(const arena_t *arena);
 extent_hooks_t *arena_set_extent_hooks(
     tsd_t *tsd, arena_t *arena, extent_hooks_t *extent_hooks);
 bool    arena_dss_prec_set(arena_t *arena, dss_prec_t dss_prec);
-void    arena_name_get(arena_t *arena, char *name);
+void    arena_name_get(const arena_t *arena, char *name);
 void    arena_name_set(arena_t *arena, const char *name);
 ssize_t arena_dirty_decay_ms_default_get(void);
 bool    arena_dirty_decay_ms_default_set(ssize_t decay_ms);
@@ -101,7 +101,7 @@ ssize_t arena_muzzy_decay_ms_default_get(void);
 bool    arena_muzzy_decay_ms_default_set(ssize_t decay_ms);
 bool    arena_retain_grow_limit_get_set(
        tsd_t *tsd, arena_t *arena, size_t *old_limit, size_t *new_limit);
-unsigned arena_nthreads_get(arena_t *arena, bool internal);
+unsigned arena_nthreads_get(const arena_t *arena, bool internal);
 void     arena_nthreads_inc(arena_t *arena, bool internal);
 void     arena_nthreads_dec(arena_t *arena, bool internal);
 arena_t *arena_new(tsdn_t *tsdn, unsigned ind, const arena_config_t *config);
diff --git a/include/jemalloc/internal/arena_inlines_a.h b/include/jemalloc/internal/arena_inlines_a.h
index 214ce80b..a899928c 100644
--- a/include/jemalloc/internal/arena_inlines_a.h
+++ b/include/jemalloc/internal/arena_inlines_a.h
@@ -20,7 +20,7 @@ arena_internal_sub(arena_t *arena, size_t size) {
 }
 
 static inline size_t
-arena_internal_get(arena_t *arena) {
+arena_internal_get(const arena_t *arena) {
 	return atomic_load_zu(&arena->stats.internal, ATOMIC_RELAXED);
 }
 
diff --git a/include/jemalloc/internal/bin_inlines.h b/include/jemalloc/internal/bin_inlines.h
index f4291169..31fe4818 100644
--- a/include/jemalloc/internal/bin_inlines.h
+++ b/include/jemalloc/internal/bin_inlines.h
@@ -24,8 +24,8 @@ struct bin_dalloc_locked_info_s {
 
 /* Find the region index of a pointer within a slab. */
 JEMALLOC_ALWAYS_INLINE size_t
-bin_slab_regind_impl(
-    div_info_t *div_info, szind_t binind, edata_t *slab, const void *ptr) {
+bin_slab_regind_impl(const div_info_t *div_info, szind_t binind,
+    const edata_t *slab, const void *ptr) {
 	size_t diff, regind;
 
 	/* Freeing a pointer outside the slab can cause assertion failure. */
@@ -45,8 +45,8 @@ bin_slab_regind_impl(
 }
 
 JEMALLOC_ALWAYS_INLINE size_t
-bin_slab_regind(bin_dalloc_locked_info_t *info, szind_t binind,
-    edata_t *slab, const void *ptr) {
+bin_slab_regind(const bin_dalloc_locked_info_t *info, szind_t binind,
+    const edata_t *slab, const void *ptr) {
 	size_t regind = bin_slab_regind_impl(
 	    &info->div_info, binind, slab, ptr);
 	return regind;
diff --git a/include/jemalloc/internal/bitmap.h b/include/jemalloc/internal/bitmap.h
index e0f596fb..18c96f41 100644
--- a/include/jemalloc/internal/bitmap.h
+++ b/include/jemalloc/internal/bitmap.h
@@ -181,7 +181,7 @@ void   bitmap_init(bitmap_t *bitmap, const bitmap_info_t *binfo, bool fill);
 size_t bitmap_size(const bitmap_info_t *binfo);
 
 static inline bool
-bitmap_full(bitmap_t *bitmap, const bitmap_info_t *binfo) {
+bitmap_full(const bitmap_t *bitmap, const bitmap_info_t *binfo) {
 #ifdef BITMAP_USE_TREE
 	size_t   rgoff = binfo->levels[binfo->nlevels].group_offset - 1;
 	bitmap_t rg = bitmap[rgoff];
@@ -200,7 +200,7 @@ bitmap_full(bitmap_t *bitmap, const bitmap_info_t *binfo) {
 }
 
 static inline bool
-bitmap_get(bitmap_t *bitmap, const bitmap_info_t *binfo, size_t bit) {
+bitmap_get(const bitmap_t *bitmap, const bitmap_info_t *binfo, size_t bit) {
 	size_t   goff;
 	bitmap_t g;
 
diff --git a/include/jemalloc/internal/div.h b/include/jemalloc/internal/div.h
index 56d5f463..472665fb 100644
--- a/include/jemalloc/internal/div.h
+++ b/include/jemalloc/internal/div.h
@@ -24,7 +24,7 @@ struct div_info_s {
 void div_init(div_info_t *div_info, size_t divisor);
 
 static inline size_t
-div_compute(div_info_t *div_info, size_t n) {
+div_compute(const div_info_t *div_info, size_t n) {
 	assert(n <= (uint32_t)-1);
 	/*
 	 * This generates, e.g. mov; imul; shr on x86-64. On a 32-bit machine,
diff --git a/include/jemalloc/internal/ecache.h b/include/jemalloc/internal/ecache.h
index 605733b5..affc0ff3 100644
--- a/include/jemalloc/internal/ecache.h
+++ b/include/jemalloc/internal/ecache.h
@@ -23,27 +23,27 @@ struct ecache_s {
 };
 
 static inline size_t
-ecache_npages_get(ecache_t *ecache) {
+ecache_npages_get(const ecache_t *ecache) {
 	return eset_npages_get(&ecache->eset)
 	    + eset_npages_get(&ecache->guarded_eset);
 }
 
 /* Get the number of extents in the given page size index. */
 static inline size_t
-ecache_nextents_get(ecache_t *ecache, pszind_t ind) {
+ecache_nextents_get(const ecache_t *ecache, pszind_t ind) {
 	return eset_nextents_get(&ecache->eset, ind)
 	    + eset_nextents_get(&ecache->guarded_eset, ind);
 }
 
 /* Get the sum total bytes of the extents in the given page size index. */
 static inline size_t
-ecache_nbytes_get(ecache_t *ecache, pszind_t ind) {
+ecache_nbytes_get(const ecache_t *ecache, pszind_t ind) {
 	return eset_nbytes_get(&ecache->eset, ind)
 	    + eset_nbytes_get(&ecache->guarded_eset, ind);
 }
 
 static inline unsigned
-ecache_ind_get(ecache_t *ecache) {
+ecache_ind_get(const ecache_t *ecache) {
 	return ecache->ind;
 }
 
diff --git a/include/jemalloc/internal/edata.h b/include/jemalloc/internal/edata.h
index 06b6c545..af3676ff 100644
--- a/include/jemalloc/internal/edata.h
+++ b/include/jemalloc/internal/edata.h
@@ -645,7 +645,7 @@ edata_prof_recent_alloc_set_dont_call_directly(
 }
 
 static inline bool
-edata_is_head_get(edata_t *edata) {
+edata_is_head_get(const edata_t *edata) {
 	return (bool)((edata->e_bits & EDATA_BITS_IS_HEAD_MASK)
 	    >> EDATA_BITS_IS_HEAD_SHIFT);
 }
diff --git a/include/jemalloc/internal/ehooks.h b/include/jemalloc/internal/ehooks.h
index c65e189a..a5880a4d 100644
--- a/include/jemalloc/internal/ehooks.h
+++ b/include/jemalloc/internal/ehooks.h
@@ -110,12 +110,12 @@ ehooks_set_extent_hooks_ptr(ehooks_t *ehooks, extent_hooks_t *extent_hooks) {
 }
 
 static inline extent_hooks_t *
-ehooks_get_extent_hooks_ptr(ehooks_t *ehooks) {
+ehooks_get_extent_hooks_ptr(const ehooks_t *ehooks) {
 	return (extent_hooks_t *)atomic_load_p(&ehooks->ptr, ATOMIC_ACQUIRE);
 }
 
 static inline bool
-ehooks_are_default(ehooks_t *ehooks) {
+ehooks_are_default(const ehooks_t *ehooks) {
 	return ehooks_get_extent_hooks_ptr(ehooks)
 	    == &ehooks_default_extent_hooks;
 }
@@ -126,7 +126,7 @@ ehooks_are_default(ehooks_t *ehooks) {
  * include some checks for such cases.
  */
 static inline bool
-ehooks_dalloc_will_fail(ehooks_t *ehooks) {
+ehooks_dalloc_will_fail(const ehooks_t *ehooks) {
 	if (ehooks_are_default(ehooks)) {
 		return opt_retain;
 	} else {
@@ -135,17 +135,17 @@ ehooks_dalloc_will_fail(ehooks_t *ehooks) {
 }
 
 static inline bool
-ehooks_split_will_fail(ehooks_t *ehooks) {
+ehooks_split_will_fail(const ehooks_t *ehooks) {
 	return ehooks_get_extent_hooks_ptr(ehooks)->split == NULL;
 }
 
 static inline bool
-ehooks_merge_will_fail(ehooks_t *ehooks) {
+ehooks_merge_will_fail(const ehooks_t *ehooks) {
 	return ehooks_get_extent_hooks_ptr(ehooks)->merge == NULL;
 }
 
 static inline bool
-ehooks_guard_will_fail(ehooks_t *ehooks) {
+ehooks_guard_will_fail(const ehooks_t *ehooks) {
 	/*
 	 * Before the guard hooks are officially introduced, limit the use to
 	 * the default hooks only.
diff --git a/include/jemalloc/internal/eset.h b/include/jemalloc/internal/eset.h
index 9b7c4a89..a4cae8c5 100644
--- a/include/jemalloc/internal/eset.h
+++ b/include/jemalloc/internal/eset.h
@@ -60,11 +60,11 @@ struct eset_s {
 
 void eset_init(eset_t *eset, extent_state_t state);
 
-size_t eset_npages_get(eset_t *eset);
+size_t eset_npages_get(const eset_t *eset);
 /* Get the number of extents in the given page size index. */
-size_t eset_nextents_get(eset_t *eset, pszind_t ind);
+size_t eset_nextents_get(const eset_t *eset, pszind_t ind);
 /* Get the sum total bytes of the extents in the given page size index. */
-size_t eset_nbytes_get(eset_t *eset, pszind_t ind);
+size_t eset_nbytes_get(const eset_t *eset, pszind_t ind);
 
 void eset_insert(eset_t *eset, edata_t *edata);
 void eset_remove(eset_t *eset, edata_t *edata);
diff --git a/include/jemalloc/internal/extent.h b/include/jemalloc/internal/extent.h
index a9f81cb7..28b8e2d4 100644
--- a/include/jemalloc/internal/extent.h
+++ b/include/jemalloc/internal/extent.h
@@ -91,7 +91,7 @@ extent_neighbor_head_state_mergeable(
 }
 
 JEMALLOC_ALWAYS_INLINE bool
-extent_can_acquire_neighbor(edata_t *edata, rtree_contents_t contents,
+extent_can_acquire_neighbor(const edata_t *edata, rtree_contents_t contents,
     extent_pai_t pai, extent_state_t expected_state, bool forward,
     bool expanding) {
 	edata_t *neighbor = contents.edata;
diff --git a/include/jemalloc/internal/fb.h b/include/jemalloc/internal/fb.h
index bf76f362..9ee25005 100644
--- a/include/jemalloc/internal/fb.h
+++ b/include/jemalloc/internal/fb.h
@@ -25,7 +25,7 @@ fb_init(fb_group_t *fb, size_t nbits) {
 }
 
 static inline bool
-fb_empty(fb_group_t *fb, size_t nbits) {
+fb_empty(const fb_group_t *fb, size_t nbits) {
 	size_t ngroups = FB_NGROUPS(nbits);
 	for (size_t i = 0; i < ngroups; i++) {
 		if (fb[i] != 0) {
@@ -36,7 +36,7 @@ fb_empty(fb_group_t *fb, size_t nbits) {
 }
 
 static inline bool
-fb_full(fb_group_t *fb, size_t nbits) {
+fb_full(const fb_group_t *fb, size_t nbits) {
 	size_t ngroups = FB_NGROUPS(nbits);
 	size_t trailing_bits = nbits % FB_GROUP_BITS;
 	size_t limit = (trailing_bits == 0 ? ngroups : ngroups - 1);
@@ -52,7 +52,7 @@ fb_full(fb_group_t *fb, size_t nbits) {
 }
 
 static inline bool
-fb_get(fb_group_t *fb, size_t nbits, size_t bit) {
+fb_get(const fb_group_t *fb, size_t nbits, size_t bit) {
 	assert(bit < nbits);
 	size_t group_ind = bit / FB_GROUP_BITS;
 	size_t bit_ind = bit % FB_GROUP_BITS;
@@ -156,15 +156,21 @@ fb_scount_visitor(void *ctx, fb_group_t *fb, fb_group_t mask) {
 
 /* Finds the number of set bit in the of length cnt starting at start. */
 JEMALLOC_ALWAYS_INLINE size_t
-fb_scount(fb_group_t *fb, size_t nbits, size_t start, size_t cnt) {
+fb_scount(const fb_group_t *fb, size_t nbits, size_t start, size_t cnt) {
 	size_t scount = 0;
-	fb_visit_impl(fb, nbits, &fb_scount_visitor, &scount, start, cnt);
+	/*
+	 * fb_visit_impl is shared with mutating visitors (e.g. fb_set_range),
+	 * so it takes a non-const fb.  fb_scount_visitor only reads, so the
+	 * cast is safe.
+	 */
+	fb_visit_impl((fb_group_t *)fb, nbits, &fb_scount_visitor, &scount,
+	    start, cnt);
 	return scount;
 }
 
 /* Finds the number of unset bit in the of length cnt starting at start. */
 JEMALLOC_ALWAYS_INLINE size_t
-fb_ucount(fb_group_t *fb, size_t nbits, size_t start, size_t cnt) {
+fb_ucount(const fb_group_t *fb, size_t nbits, size_t start, size_t cnt) {
 	size_t scount = fb_scount(fb, nbits, start, cnt);
 	return cnt - scount;
 }
@@ -176,8 +182,8 @@ fb_ucount(fb_group_t *fb, size_t nbits, size_t start, size_t cnt) {
  * Returns the number of bits in the bitmap if no such bit exists.
  */
 JEMALLOC_ALWAYS_INLINE ssize_t
-fb_find_impl(
-    fb_group_t *fb, size_t nbits, size_t start, bool val, bool forward) {
+fb_find_impl(const fb_group_t *fb, size_t nbits, size_t start, bool val,
+    bool forward) {
 	assert(start < nbits);
 	size_t  ngroups = FB_NGROUPS(nbits);
 	ssize_t group_ind = start / FB_GROUP_BITS;
@@ -226,14 +232,14 @@ fb_find_impl(
  * number of bits in the bitmap if no such bit exists.
  */
 static inline size_t
-fb_ffu(fb_group_t *fb, size_t nbits, size_t min_bit) {
+fb_ffu(const fb_group_t *fb, size_t nbits, size_t min_bit) {
 	return (size_t)fb_find_impl(fb, nbits, min_bit, /* val */ false,
 	    /* forward */ true);
 }
 
 /* The same, but looks for an unset bit. */
 static inline size_t
-fb_ffs(fb_group_t *fb, size_t nbits, size_t min_bit) {
+fb_ffs(const fb_group_t *fb, size_t nbits, size_t min_bit) {
 	return (size_t)fb_find_impl(fb, nbits, min_bit, /* val */ true,
 	    /* forward */ true);
 }
@@ -243,21 +249,21 @@ fb_ffs(fb_group_t *fb, size_t nbits, size_t min_bit) {
  * no such bit exists.
  */
 static inline ssize_t
-fb_flu(fb_group_t *fb, size_t nbits, size_t max_bit) {
+fb_flu(const fb_group_t *fb, size_t nbits, size_t max_bit) {
 	return fb_find_impl(fb, nbits, max_bit, /* val */ false,
 	    /* forward */ false);
 }
 
 static inline ssize_t
-fb_fls(fb_group_t *fb, size_t nbits, size_t max_bit) {
+fb_fls(const fb_group_t *fb, size_t nbits, size_t max_bit) {
 	return fb_find_impl(fb, nbits, max_bit, /* val */ true,
 	    /* forward */ false);
 }
 
 /* Returns whether or not we found a range. */
 JEMALLOC_ALWAYS_INLINE bool
-fb_iter_range_impl(fb_group_t *fb, size_t nbits, size_t start, size_t *r_begin,
-    size_t *r_len, bool val, bool forward) {
+fb_iter_range_impl(const fb_group_t *fb, size_t nbits, size_t start,
+    size_t *r_begin, size_t *r_len, bool val, bool forward) {
 	assert(start < nbits);
 	ssize_t next_range_begin = fb_find_impl(fb, nbits, start, val, forward);
 	if ((forward && next_range_begin == (ssize_t)nbits)
@@ -286,8 +292,8 @@ fb_iter_range_impl(fb_group_t *fb, size_t nbits, size_t start, size_t *r_begin,
  * touching *r_begin or *r_end).
  */
 static inline bool
-fb_srange_iter(fb_group_t *fb, size_t nbits, size_t start, size_t *r_begin,
-    size_t *r_len) {
+fb_srange_iter(const fb_group_t *fb, size_t nbits, size_t start,
+    size_t *r_begin, size_t *r_len) {
 	return fb_iter_range_impl(fb, nbits, start, r_begin, r_len,
 	    /* val */ true, /* forward */ true);
 }
@@ -297,30 +303,30 @@ fb_srange_iter(fb_group_t *fb, size_t nbits, size_t start, size_t *r_begin,
  * forwards.  (The position returned is still the earliest bit in the range).
  */
 static inline bool
-fb_srange_riter(fb_group_t *fb, size_t nbits, size_t start, size_t *r_begin,
-    size_t *r_len) {
+fb_srange_riter(const fb_group_t *fb, size_t nbits, size_t start,
+    size_t *r_begin, size_t *r_len) {
 	return fb_iter_range_impl(fb, nbits, start, r_begin, r_len,
 	    /* val */ true, /* forward */ false);
 }
 
 /* Similar to fb_srange_iter, but searches for unset bits. */
 static inline bool
-fb_urange_iter(fb_group_t *fb, size_t nbits, size_t start, size_t *r_begin,
-    size_t *r_len) {
+fb_urange_iter(const fb_group_t *fb, size_t nbits, size_t start,
+    size_t *r_begin, size_t *r_len) {
 	return fb_iter_range_impl(fb, nbits, start, r_begin, r_len,
 	    /* val */ false, /* forward */ true);
 }
 
 /* Similar to fb_srange_riter, but searches for unset bits. */
 static inline bool
-fb_urange_riter(fb_group_t *fb, size_t nbits, size_t start, size_t *r_begin,
-    size_t *r_len) {
+fb_urange_riter(const fb_group_t *fb, size_t nbits, size_t start,
+    size_t *r_begin, size_t *r_len) {
 	return fb_iter_range_impl(fb, nbits, start, r_begin, r_len,
 	    /* val */ false, /* forward */ false);
 }
 
 JEMALLOC_ALWAYS_INLINE size_t
-fb_range_longest_impl(fb_group_t *fb, size_t nbits, bool val) {
+fb_range_longest_impl(const fb_group_t *fb, size_t nbits, bool val) {
 	size_t begin = 0;
 	size_t longest_len = 0;
 	size_t len = 0;
@@ -336,12 +342,12 @@ fb_range_longest_impl(fb_group_t *fb, size_t nbits, bool val) {
 }
 
 static inline size_t
-fb_srange_longest(fb_group_t *fb, size_t nbits) {
+fb_srange_longest(const fb_group_t *fb, size_t nbits) {
 	return fb_range_longest_impl(fb, nbits, /* val */ true);
 }
 
 static inline size_t
-fb_urange_longest(fb_group_t *fb, size_t nbits) {
+fb_urange_longest(const fb_group_t *fb, size_t nbits) {
 	return fb_range_longest_impl(fb, nbits, /* val */ false);
 }
 
diff --git a/include/jemalloc/internal/hpdata.h b/include/jemalloc/internal/hpdata.h
index a9c507f0..48929311 100644
--- a/include/jemalloc/internal/hpdata.h
+++ b/include/jemalloc/internal/hpdata.h
@@ -209,7 +209,7 @@ hpdata_allow_hugify(hpdata_t *hpdata, nstime_t now) {
 }
 
 static inline nstime_t
-hpdata_time_hugify_allowed(hpdata_t *hpdata) {
+hpdata_time_hugify_allowed(const hpdata_t *hpdata) {
 	return hpdata->h_time_hugify_allowed;
 }
 
@@ -305,7 +305,7 @@ hpdata_ndirty_get(const hpdata_t *hpdata) {
 }
 
 static inline size_t
-hpdata_nretained_get(hpdata_t *hpdata) {
+hpdata_nretained_get(const hpdata_t *hpdata) {
 	return HUGEPAGE_PAGES - hpdata->h_ntouched;
 }
 
@@ -330,7 +330,7 @@ hpdata_purged_when_empty_and_huge_set(hpdata_t *hpdata, bool v) {
 }
 
 static inline void
-hpdata_assert_empty(hpdata_t *hpdata) {
+hpdata_assert_empty(const hpdata_t *hpdata) {
 	assert(fb_empty(hpdata->active_pages, HUGEPAGE_PAGES));
 	assert(hpdata->h_nactive == 0);
 }
@@ -341,7 +341,7 @@ hpdata_assert_empty(hpdata_t *hpdata) {
  * match computed ones).
  */
 static inline bool
-hpdata_consistent(hpdata_t *hpdata) {
+hpdata_consistent(const hpdata_t *hpdata) {
 	bool res = true;
 
 	const size_t active_urange_longest = fb_urange_longest(
diff --git a/include/jemalloc/internal/jemalloc_internal_inlines_b.h b/include/jemalloc/internal/jemalloc_internal_inlines_b.h
index 1cfb5fda..bf98ee88 100644
--- a/include/jemalloc/internal/jemalloc_internal_inlines_b.h
+++ b/include/jemalloc/internal/jemalloc_internal_inlines_b.h
@@ -98,7 +98,7 @@ arena_ichoose(tsd_t *tsd, arena_t *arena) {
 }
 
 static inline bool
-arena_is_auto(arena_t *arena) {
+arena_is_auto(const arena_t *arena) {
 	assert(narenas_auto > 0);
 
 	return (arena_ind_get(arena) < manual_arena_base);
diff --git a/include/jemalloc/internal/pa.h b/include/jemalloc/internal/pa.h
index f3910ad8..2c1e6369 100644
--- a/include/jemalloc/internal/pa.h
+++ b/include/jemalloc/internal/pa.h
@@ -120,7 +120,7 @@ pa_shard_dont_decay_muzzy(pa_shard_t *shard) {
 }
 
 static inline ehooks_t *
-pa_shard_ehooks_get(pa_shard_t *shard) {
+pa_shard_ehooks_get(const pa_shard_t *shard) {
 	return base_ehooks_get(shard->base);
 }
 
@@ -221,12 +221,12 @@ void pa_shard_prefork5(tsdn_t *tsdn, pa_shard_t *shard);
 void pa_shard_postfork_parent(tsdn_t *tsdn, pa_shard_t *shard);
 void pa_shard_postfork_child(tsdn_t *tsdn, pa_shard_t *shard);
 
-size_t pa_shard_nactive(pa_shard_t *shard);
-size_t pa_shard_ndirty(pa_shard_t *shard);
-size_t pa_shard_nmuzzy(pa_shard_t *shard);
+size_t pa_shard_nactive(const pa_shard_t *shard);
+size_t pa_shard_ndirty(const pa_shard_t *shard);
+size_t pa_shard_nmuzzy(const pa_shard_t *shard);
 
 void pa_shard_basic_stats_merge(
-    pa_shard_t *shard, size_t *nactive, size_t *ndirty, size_t *nmuzzy);
+    const pa_shard_t *shard, size_t *nactive, size_t *ndirty, size_t *nmuzzy);
 
 void pa_shard_stats_merge(tsdn_t *tsdn, pa_shard_t *shard,
     pa_shard_stats_t *pa_shard_stats_out, pac_estats_t *estats_out,
diff --git a/include/jemalloc/internal/pac.h b/include/jemalloc/internal/pac.h
index a19c8b35..286be2b9 100644
--- a/include/jemalloc/internal/pac.h
+++ b/include/jemalloc/internal/pac.h
@@ -156,12 +156,12 @@ bool pac_init(tsdn_t *tsdn, pac_t *pac, base_t *base, emap_t *emap,
     malloc_mutex_t *stats_mtx);
 
 static inline size_t
-pac_mapped(pac_t *pac) {
+pac_mapped(const pac_t *pac) {
 	return atomic_load_zu(&pac->stats->pac_mapped, ATOMIC_RELAXED);
 }
 
 static inline ehooks_t *
-pac_ehooks_get(pac_t *pac) {
+pac_ehooks_get(const pac_t *pac) {
 	return base_ehooks_get(pac->base);
 }
 
diff --git a/include/jemalloc/internal/psset.h b/include/jemalloc/internal/psset.h
index f096e414..fad2981e 100644
--- a/include/jemalloc/internal/psset.h
+++ b/include/jemalloc/internal/psset.h
@@ -134,17 +134,17 @@ void psset_insert(psset_t *psset, hpdata_t *ps);
 void psset_remove(psset_t *psset, hpdata_t *ps);
 
 static inline size_t
-psset_npageslabs(psset_t *psset) {
+psset_npageslabs(const psset_t *psset) {
 	return psset->stats.merged.npageslabs;
 }
 
 static inline size_t
-psset_nactive(psset_t *psset) {
+psset_nactive(const psset_t *psset) {
 	return psset->stats.merged.nactive;
 }
 
 static inline size_t
-psset_ndirty(psset_t *psset) {
+psset_ndirty(const psset_t *psset) {
 	return psset->stats.merged.ndirty;
 }
 
diff --git a/include/jemalloc/internal/tcache_inlines.h b/include/jemalloc/internal/tcache_inlines.h
index 5f8ed317..a9dba26a 100644
--- a/include/jemalloc/internal/tcache_inlines.h
+++ b/include/jemalloc/internal/tcache_inlines.h
@@ -19,7 +19,7 @@ tcache_enabled_get(tsd_t *tsd) {
 }
 
 static inline unsigned
-tcache_nbins_get(tcache_slow_t *tcache_slow) {
+tcache_nbins_get(const tcache_slow_t *tcache_slow) {
 	assert(tcache_slow != NULL);
 	unsigned nbins = tcache_slow->tcache_nbins;
 	assert(nbins <= TCACHE_NBINS_MAX);
@@ -27,7 +27,7 @@ tcache_nbins_get(tcache_slow_t *tcache_slow) {
 }
 
 static inline size_t
-tcache_max_get(tcache_slow_t *tcache_slow) {
+tcache_max_get(const tcache_slow_t *tcache_slow) {
 	assert(tcache_slow != NULL);
 	size_t tcache_max = sz_index2size(tcache_nbins_get(tcache_slow) - 1);
 	assert(tcache_max <= TCACHE_MAXCLASS_LIMIT);
diff --git a/src/arena.c b/src/arena.c
index 559ec47a..7d9bf1df 100644
--- a/src/arena.c
+++ b/src/arena.c
@@ -343,7 +343,8 @@ arena_extent_alloc_large(
 }
 
 void
-arena_extent_dalloc_large_prep(tsdn_t *tsdn, arena_t *arena, edata_t *edata) {
+arena_extent_dalloc_large_prep(tsdn_t *tsdn, arena_t *arena,
+    const edata_t *edata) {
 	if (config_stats) {
 		arena_large_dalloc_stats_update(
 		    tsdn, arena, edata_usize_get(edata));
@@ -352,7 +353,7 @@ arena_extent_dalloc_large_prep(tsdn_t *tsdn, arena_t *arena, edata_t *edata) {
 
 void
 arena_extent_ralloc_large_shrink(
-    tsdn_t *tsdn, arena_t *arena, edata_t *edata, size_t oldusize) {
+    tsdn_t *tsdn, arena_t *arena, const edata_t *edata, size_t oldusize) {
 	size_t usize = edata_usize_get(edata);
 
 	if (config_stats) {
@@ -362,7 +363,7 @@ arena_extent_ralloc_large_shrink(
 
 void
 arena_extent_ralloc_large_expand(
-    tsdn_t *tsdn, arena_t *arena, edata_t *edata, size_t oldusize) {
+    tsdn_t *tsdn, arena_t *arena, const edata_t *edata, size_t oldusize) {
 	size_t usize = edata_usize_get(edata);
 
 	if (config_stats) {
@@ -1662,7 +1663,7 @@ arena_ralloc(tsdn_t *tsdn, arena_t *arena, void *ptr, size_t oldsize,
 }
 
 ehooks_t *
-arena_get_ehooks(arena_t *arena) {
+arena_get_ehooks(const arena_t *arena) {
 	return base_ehooks_get(arena->base);
 }
 
@@ -1685,7 +1686,7 @@ arena_set_extent_hooks(
 }
 
 dss_prec_t
-arena_dss_prec_get(arena_t *arena) {
+arena_dss_prec_get(const arena_t *arena) {
 	return (dss_prec_t)atomic_load_u(&arena->dss_prec, ATOMIC_ACQUIRE);
 }
 
@@ -1699,8 +1700,9 @@ arena_dss_prec_set(arena_t *arena, dss_prec_t dss_prec) {
 }
 
 void
-arena_name_get(arena_t *arena, char *name) {
-	char *end = (char *)memchr((void *)arena->name, '\0', ARENA_NAME_LEN);
+arena_name_get(const arena_t *arena, char *name) {
+	const char *end = (const char *)memchr(
+	    arena->name, '\0', ARENA_NAME_LEN);
 	assert(end != NULL);
 	size_t len = (uintptr_t)end - (uintptr_t)arena->name + 1;
 	assert(len > 0 && len <= ARENA_NAME_LEN);
@@ -1751,7 +1753,7 @@ arena_retain_grow_limit_get_set(
 }
 
 unsigned
-arena_nthreads_get(arena_t *arena, bool internal) {
+arena_nthreads_get(const arena_t *arena, bool internal) {
 	return atomic_load_u(&arena->nthreads[internal], ATOMIC_RELAXED);
 }
 
diff --git a/src/base.c b/src/base.c
index ef7f0dd4..a47b6a37 100644
--- a/src/base.c
+++ b/src/base.c
@@ -112,7 +112,7 @@ label_done:
 }
 
 static inline bool
-base_edata_is_reused(edata_t *edata) {
+base_edata_is_reused(const edata_t *edata) {
 	/*
 	 * Borrow the guarded bit to indicate if the extent is a recycled one,
 	 * i.e. the ones returned to base for reuse; currently only tcache bin
@@ -133,8 +133,8 @@ base_edata_init(
 }
 
 static size_t
-base_get_num_blocks(base_t *base, bool with_new_block) {
-	base_block_t *b = base->blocks;
+base_get_num_blocks(const base_t *base, bool with_new_block) {
+	const base_block_t *b = base->blocks;
 	assert(b != NULL);
 
 	size_t n_blocks = with_new_block ? 2 : 1;
diff --git a/src/eset.c b/src/eset.c
index 4a427d78..7db57ee9 100644
--- a/src/eset.c
+++ b/src/eset.c
@@ -32,17 +32,17 @@ eset_init(eset_t *eset, extent_state_t state) {
 }
 
 size_t
-eset_npages_get(eset_t *eset) {
+eset_npages_get(const eset_t *eset) {
 	return atomic_load_zu(&eset->npages, ATOMIC_RELAXED);
 }
 
 size_t
-eset_nextents_get(eset_t *eset, pszind_t pind) {
+eset_nextents_get(const eset_t *eset, pszind_t pind) {
 	return atomic_load_zu(&eset->bin_stats[pind].nextents, ATOMIC_RELAXED);
 }
 
 size_t
-eset_nbytes_get(eset_t *eset, pszind_t pind) {
+eset_nbytes_get(const eset_t *eset, pszind_t pind) {
 	return atomic_load_zu(&eset->bin_stats[pind].nbytes, ATOMIC_RELAXED);
 }
 
diff --git a/src/pa_extra.c b/src/pa_extra.c
index ff45674f..8d4c3562 100644
--- a/src/pa_extra.c
+++ b/src/pa_extra.c
@@ -73,12 +73,12 @@ pa_shard_postfork_child(tsdn_t *tsdn, pa_shard_t *shard) {
 }
 
 size_t
-pa_shard_nactive(pa_shard_t *shard) {
+pa_shard_nactive(const pa_shard_t *shard) {
 	return atomic_load_zu(&shard->nactive, ATOMIC_RELAXED);
 }
 
 size_t
-pa_shard_ndirty(pa_shard_t *shard) {
+pa_shard_ndirty(const pa_shard_t *shard) {
 	size_t ndirty = ecache_npages_get(&shard->pac.ecache_dirty);
 	if (shard->ever_used_hpa) {
 		ndirty += psset_ndirty(&shard->hpa_shard.psset);
@@ -87,13 +87,13 @@ pa_shard_ndirty(pa_shard_t *shard) {
 }
 
 size_t
-pa_shard_nmuzzy(pa_shard_t *shard) {
+pa_shard_nmuzzy(const pa_shard_t *shard) {
 	return ecache_npages_get(&shard->pac.ecache_muzzy);
 }
 
 void
 pa_shard_basic_stats_merge(
-    pa_shard_t *shard, size_t *nactive, size_t *ndirty, size_t *nmuzzy) {
+    const pa_shard_t *shard, size_t *nactive, size_t *ndirty, size_t *nmuzzy) {
 	*nactive += pa_shard_nactive(shard);
 	*ndirty += pa_shard_ndirty(shard);
 	*nmuzzy += pa_shard_nmuzzy(shard);