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daanx 2024-12-21 15:48:49 -08:00
commit 1a6fbdf0b2
5 changed files with 431 additions and 87 deletions
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50
include/mimalloc/atomic.h
View file

@ -1,5 +1,5 @@
/* ----------------------------------------------------------------------------
Copyright (c) 2018-2023 Microsoft Research, Daan Leijen
Copyright (c) 2018-2024 Microsoft Research, Daan Leijen
This is free software; you can redistribute it and/or modify it under the
terms of the MIT license. A copy of the license can be found in the file
"LICENSE" at the root of this distribution.
@ -419,28 +419,7 @@ static inline void mi_atomic_yield(void) {
#if defined(_WIN32)
#if 0
#define mi_lock_t CRITICAL_SECTION
static inline bool mi_lock_try_acquire(mi_lock_t* lock) {
return TryEnterCriticalSection(lock);
}
static inline void mi_lock_acquire(mi_lock_t* lock) {
EnterCriticalSection(lock);
}
static inline void mi_lock_release(mi_lock_t* lock) {
LeaveCriticalSection(lock);
}
static inline void mi_lock_init(mi_lock_t* lock) {
InitializeCriticalSection(lock);
}
static inline void mi_lock_done(mi_lock_t* lock) {
DeleteCriticalSection(lock);
}
#else
#if 1
#define mi_lock_t SRWLOCK // slim reader-writer lock
static inline bool mi_lock_try_acquire(mi_lock_t* lock) {
@ -459,10 +438,31 @@ static inline void mi_lock_done(mi_lock_t* lock) {
(void)(lock);
}
#else
#define mi_lock_t CRITICAL_SECTION
static inline bool mi_lock_try_acquire(mi_lock_t* lock) {
return TryEnterCriticalSection(lock);
}
static inline void mi_lock_acquire(mi_lock_t* lock) {
EnterCriticalSection(lock);
}
static inline void mi_lock_release(mi_lock_t* lock) {
LeaveCriticalSection(lock);
}
static inline void mi_lock_init(mi_lock_t* lock) {
InitializeCriticalSection(lock);
}
static inline void mi_lock_done(mi_lock_t* lock) {
DeleteCriticalSection(lock);
}
#endif
#elif defined(MI_USE_PTHREADS)
void _mi_error_message(int err, const char* fmt, ...);
#define mi_lock_t pthread_mutex_t
static inline bool mi_lock_try_acquire(mi_lock_t* lock) {
@ -471,7 +471,7 @@ static inline bool mi_lock_try_acquire(mi_lock_t* lock) {
static inline void mi_lock_acquire(mi_lock_t* lock) {
const int err = pthread_mutex_lock(lock);
if (err != 0) {
mi_error_message(EFAULT, "internal error: lock cannot be acquired\n");
_mi_error_message(err, "internal error: lock cannot be acquired\n");
}
}
static inline void mi_lock_release(mi_lock_t* lock) {
@ -535,6 +535,4 @@ static inline void mi_lock_done(mi_lock_t* lock) {
#endif
#endif // MI_ATOMIC_H

1
include/mimalloc/types.h
View file

@ -545,6 +545,7 @@ typedef struct mi_subproc_s {
_Atomic(size_t) arena_count; // current count of arena's
_Atomic(mi_arena_t*) arenas[MI_MAX_ARENAS]; // arena's of this sub-process
mi_lock_t arena_reserve_lock; // lock to ensure arena's get reserved one at a time
_Atomic(int64_t) purge_expire; // expiration is set if any arenas can be purged
_Atomic(size_t) abandoned_count[MI_BIN_COUNT]; // total count of abandoned pages for this sub-process
mi_page_t* os_abandoned_pages; // list of pages that OS allocated and not in an arena (only used if `mi_option_visit_abandoned` is on)

346
src/arena-abandon.c Normal file
View file

@ -0,0 +1,346 @@
/* ----------------------------------------------------------------------------
Copyright (c) 2019-2024, Microsoft Research, Daan Leijen
This is free software; you can redistribute it and/or modify it under the
terms of the MIT license. A copy of the license can be found in the file
"LICENSE" at the root of this distribution.
-----------------------------------------------------------------------------*/
#if !defined(MI_IN_ARENA_C)
#error "this file should be included from 'arena.c' (so mi_arena_t is visible)"
// add includes help an IDE
#include "mimalloc.h"
#include "mimalloc/internal.h"
#include "bitmap.h"
#endif
// Minimal exports for arena-abandoned.
size_t mi_arena_id_index(mi_arena_id_t id);
mi_arena_t* mi_arena_from_index(size_t idx);
size_t mi_arena_get_count(void);
void* mi_arena_block_start(mi_arena_t* arena, mi_bitmap_index_t bindex);
bool mi_arena_memid_indices(mi_memid_t memid, size_t* arena_index, mi_bitmap_index_t* bitmap_index);
/* -----------------------------------------------------------
Abandoned blocks/segments:
_mi_arena_segment_clear_abandoned
_mi_arena_segment_mark_abandoned
This is used to atomically abandon/reclaim segments
(and crosses the arena API but it is convenient to have here).
Abandoned segments still have live blocks; they get reclaimed
when a thread frees a block in it, or when a thread needs a fresh
segment.
Abandoned segments are atomically marked in the `block_abandoned`
bitmap of arenas. Any segments allocated outside arenas are put
in the sub-process `abandoned_os_list`. This list is accessed
using locks but this should be uncommon and generally uncontended.
Reclaim and visiting either scan through the `block_abandoned`
bitmaps of the arena's, or visit the `abandoned_os_list`
A potentially nicer design is to use arena's for everything
and perhaps have virtual arena's to map OS allocated memory
but this would lack the "density" of our current arena's. TBC.
----------------------------------------------------------- */
// reclaim a specific OS abandoned segment; `true` on success.
// sets the thread_id.
static bool mi_arena_segment_os_clear_abandoned(mi_segment_t* segment, bool take_lock) {
mi_assert(segment->memid.memkind != MI_MEM_ARENA);
// not in an arena, remove from list of abandoned os segments
mi_subproc_t* const subproc = segment->subproc;
if (take_lock && !mi_lock_try_acquire(&subproc->abandoned_os_lock)) {
return false; // failed to acquire the lock, we just give up
}
// remove atomically from the abandoned os list (if possible!)
bool reclaimed = false;
mi_segment_t* const next = segment->abandoned_os_next;
mi_segment_t* const prev = segment->abandoned_os_prev;
if (next != NULL || prev != NULL || subproc->abandoned_os_list == segment) {
#if MI_DEBUG>3
// find ourselves in the abandoned list (and check the count)
bool found = false;
size_t count = 0;
for (mi_segment_t* current = subproc->abandoned_os_list; current != NULL; current = current->abandoned_os_next) {
if (current == segment) { found = true; }
count++;
}
mi_assert_internal(found);
mi_assert_internal(count == mi_atomic_load_relaxed(&subproc->abandoned_os_list_count));
#endif
// remove (atomically) from the list and reclaim
if (prev != NULL) { prev->abandoned_os_next = next; }
else { subproc->abandoned_os_list = next; }
if (next != NULL) { next->abandoned_os_prev = prev; }
else { subproc->abandoned_os_list_tail = prev; }
segment->abandoned_os_next = NULL;
segment->abandoned_os_prev = NULL;
mi_atomic_decrement_relaxed(&subproc->abandoned_count);
mi_atomic_decrement_relaxed(&subproc->abandoned_os_list_count);
if (take_lock) { // don't reset the thread_id when iterating
mi_atomic_store_release(&segment->thread_id, _mi_thread_id());
}
reclaimed = true;
}
if (take_lock) { mi_lock_release(&segment->subproc->abandoned_os_lock); }
return reclaimed;
}
// reclaim a specific abandoned segment; `true` on success.
// sets the thread_id.
bool _mi_arena_segment_clear_abandoned(mi_segment_t* segment) {
if mi_unlikely(segment->memid.memkind != MI_MEM_ARENA) {
return mi_arena_segment_os_clear_abandoned(segment, true /* take lock */);
}
// arena segment: use the blocks_abandoned bitmap.
size_t arena_idx;
size_t bitmap_idx;
mi_arena_memid_indices(segment->memid, &arena_idx, &bitmap_idx);
mi_arena_t* arena = mi_arena_from_index(arena_idx);
mi_assert_internal(arena != NULL);
// reclaim atomically
bool was_marked = _mi_bitmap_unclaim(arena->blocks_abandoned, arena->field_count, 1, bitmap_idx);
if (was_marked) {
mi_assert_internal(mi_atomic_load_acquire(&segment->thread_id) == 0);
mi_atomic_decrement_relaxed(&segment->subproc->abandoned_count);
mi_atomic_store_release(&segment->thread_id, _mi_thread_id());
}
// mi_assert_internal(was_marked);
mi_assert_internal(!was_marked || _mi_bitmap_is_claimed(arena->blocks_inuse, arena->field_count, 1, bitmap_idx));
//mi_assert_internal(arena->blocks_committed == NULL || _mi_bitmap_is_claimed(arena->blocks_committed, arena->field_count, 1, bitmap_idx));
return was_marked;
}
// mark a specific OS segment as abandoned
static void mi_arena_segment_os_mark_abandoned(mi_segment_t* segment) {
mi_assert(segment->memid.memkind != MI_MEM_ARENA);
// not in an arena; we use a list of abandoned segments
mi_subproc_t* const subproc = segment->subproc;
mi_lock(&subproc->abandoned_os_lock) {
// push on the tail of the list (important for the visitor)
mi_segment_t* prev = subproc->abandoned_os_list_tail;
mi_assert_internal(prev == NULL || prev->abandoned_os_next == NULL);
mi_assert_internal(segment->abandoned_os_prev == NULL);
mi_assert_internal(segment->abandoned_os_next == NULL);
if (prev != NULL) { prev->abandoned_os_next = segment; }
else { subproc->abandoned_os_list = segment; }
subproc->abandoned_os_list_tail = segment;
segment->abandoned_os_prev = prev;
segment->abandoned_os_next = NULL;
mi_atomic_increment_relaxed(&subproc->abandoned_os_list_count);
mi_atomic_increment_relaxed(&subproc->abandoned_count);
// and release the lock
}
return;
}
// mark a specific segment as abandoned
// clears the thread_id.
void _mi_arena_segment_mark_abandoned(mi_segment_t* segment)
{
mi_assert_internal(segment->used == segment->abandoned);
mi_atomic_store_release(&segment->thread_id, (uintptr_t)0); // mark as abandoned for multi-thread free's
if mi_unlikely(segment->memid.memkind != MI_MEM_ARENA) {
mi_arena_segment_os_mark_abandoned(segment);
return;
}
// segment is in an arena, mark it in the arena `blocks_abandoned` bitmap
size_t arena_idx;
size_t bitmap_idx;
mi_arena_memid_indices(segment->memid, &arena_idx, &bitmap_idx);
mi_arena_t* arena = mi_arena_from_index(arena_idx);
mi_assert_internal(arena != NULL);
// set abandonment atomically
mi_subproc_t* const subproc = segment->subproc; // don't access the segment after setting it abandoned
const bool was_unmarked = _mi_bitmap_claim(arena->blocks_abandoned, arena->field_count, 1, bitmap_idx, NULL);
if (was_unmarked) { mi_atomic_increment_relaxed(&subproc->abandoned_count); }
mi_assert_internal(was_unmarked);
mi_assert_internal(_mi_bitmap_is_claimed(arena->blocks_inuse, arena->field_count, 1, bitmap_idx));
}
/* -----------------------------------------------------------
Iterate through the abandoned blocks/segments using a cursor.
This is used for reclaiming and abandoned block visiting.
----------------------------------------------------------- */
// start a cursor at a randomized arena
void _mi_arena_field_cursor_init(mi_heap_t* heap, mi_subproc_t* subproc, bool visit_all, mi_arena_field_cursor_t* current) {
mi_assert_internal(heap == NULL || heap->tld->segments.subproc == subproc);
current->bitmap_idx = 0;
current->subproc = subproc;
current->visit_all = visit_all;
current->hold_visit_lock = false;
const size_t abandoned_count = mi_atomic_load_relaxed(&subproc->abandoned_count);
const size_t abandoned_list_count = mi_atomic_load_relaxed(&subproc->abandoned_os_list_count);
const size_t max_arena = mi_arena_get_count();
if (heap != NULL && heap->arena_id != _mi_arena_id_none()) {
// for a heap that is bound to one arena, only visit that arena
current->start = mi_arena_id_index(heap->arena_id);
current->end = current->start + 1;
current->os_list_count = 0;
}
else {
// otherwise visit all starting at a random location
if (abandoned_count > abandoned_list_count && max_arena > 0) {
current->start = (heap == NULL || max_arena == 0 ? 0 : (mi_arena_id_t)(_mi_heap_random_next(heap) % max_arena));
current->end = current->start + max_arena;
}
else {
current->start = 0;
current->end = 0;
}
current->os_list_count = abandoned_list_count; // max entries to visit in the os abandoned list
}
mi_assert_internal(current->start <= max_arena);
}
void _mi_arena_field_cursor_done(mi_arena_field_cursor_t* current) {
if (current->hold_visit_lock) {
mi_lock_release(&current->subproc->abandoned_os_visit_lock);
current->hold_visit_lock = false;
}
}
static mi_segment_t* mi_arena_segment_clear_abandoned_at(mi_arena_t* arena, mi_subproc_t* subproc, mi_bitmap_index_t bitmap_idx) {
// try to reclaim an abandoned segment in the arena atomically
if (!_mi_bitmap_unclaim(arena->blocks_abandoned, arena->field_count, 1, bitmap_idx)) return NULL;
mi_assert_internal(_mi_bitmap_is_claimed(arena->blocks_inuse, arena->field_count, 1, bitmap_idx));
mi_segment_t* segment = (mi_segment_t*)mi_arena_block_start(arena, bitmap_idx);
mi_assert_internal(mi_atomic_load_relaxed(&segment->thread_id) == 0);
// check that the segment belongs to our sub-process
// note: this is the reason we need the `abandoned_visit` lock in the case abandoned visiting is enabled.
// without the lock an abandoned visit may otherwise fail to visit all abandoned segments in the sub-process.
// for regular reclaim it is fine to miss one sometimes so without abandoned visiting we don't need the `abandoned_visit` lock.
if (segment->subproc != subproc) {
// it is from another sub-process, re-mark it and continue searching
const bool was_zero = _mi_bitmap_claim(arena->blocks_abandoned, arena->field_count, 1, bitmap_idx, NULL);
mi_assert_internal(was_zero); MI_UNUSED(was_zero);
return NULL;
}
else {
// success, we unabandoned a segment in our sub-process
mi_atomic_decrement_relaxed(&subproc->abandoned_count);
return segment;
}
}
static mi_segment_t* mi_arena_segment_clear_abandoned_next_field(mi_arena_field_cursor_t* previous) {
const size_t max_arena = mi_arena_get_count();
size_t field_idx = mi_bitmap_index_field(previous->bitmap_idx);
size_t bit_idx = mi_bitmap_index_bit_in_field(previous->bitmap_idx);
// visit arena's (from the previous cursor)
for (; previous->start < previous->end; previous->start++, field_idx = 0, bit_idx = 0) {
// index wraps around
size_t arena_idx = (previous->start >= max_arena ? previous->start % max_arena : previous->start);
mi_arena_t* arena = mi_arena_from_index(arena_idx);
if (arena != NULL) {
bool has_lock = false;
// visit the abandoned fields (starting at previous_idx)
for (; field_idx < arena->field_count; field_idx++, bit_idx = 0) {
size_t field = mi_atomic_load_relaxed(&arena->blocks_abandoned[field_idx]);
if mi_unlikely(field != 0) { // skip zero fields quickly
// we only take the arena lock if there are actually abandoned segments present
if (!has_lock && mi_option_is_enabled(mi_option_visit_abandoned)) {
has_lock = (previous->visit_all ? (mi_lock_acquire(&arena->abandoned_visit_lock),true) : mi_lock_try_acquire(&arena->abandoned_visit_lock));
if (!has_lock) {
if (previous->visit_all) {
_mi_error_message(EFAULT, "internal error: failed to visit all abandoned segments due to failure to acquire the visitor lock");
}
// skip to next arena
break;
}
}
mi_assert_internal(has_lock || !mi_option_is_enabled(mi_option_visit_abandoned));
// visit each set bit in the field (todo: maybe use `ctz` here?)
for (; bit_idx < MI_BITMAP_FIELD_BITS; bit_idx++) {
// pre-check if the bit is set
size_t mask = ((size_t)1 << bit_idx);
if mi_unlikely((field & mask) == mask) {
mi_bitmap_index_t bitmap_idx = mi_bitmap_index_create(field_idx, bit_idx);
mi_segment_t* const segment = mi_arena_segment_clear_abandoned_at(arena, previous->subproc, bitmap_idx);
if (segment != NULL) {
//mi_assert_internal(arena->blocks_committed == NULL || _mi_bitmap_is_claimed(arena->blocks_committed, arena->field_count, 1, bitmap_idx));
if (has_lock) { mi_lock_release(&arena->abandoned_visit_lock); }
previous->bitmap_idx = mi_bitmap_index_create_ex(field_idx, bit_idx + 1); // start at next one for the next iteration
return segment;
}
}
}
}
}
if (has_lock) { mi_lock_release(&arena->abandoned_visit_lock); }
}
}
return NULL;
}
static mi_segment_t* mi_arena_segment_clear_abandoned_next_list(mi_arena_field_cursor_t* previous) {
// go through the abandoned_os_list
// we only allow one thread per sub-process to do to visit guarded by the `abandoned_os_visit_lock`.
// The lock is released when the cursor is released.
if (!previous->hold_visit_lock) {
previous->hold_visit_lock = (previous->visit_all ? (mi_lock_acquire(&previous->subproc->abandoned_os_visit_lock),true)
: mi_lock_try_acquire(&previous->subproc->abandoned_os_visit_lock));
if (!previous->hold_visit_lock) {
if (previous->visit_all) {
_mi_error_message(EFAULT, "internal error: failed to visit all abandoned segments due to failure to acquire the OS visitor lock");
}
return NULL; // we cannot get the lock, give up
}
}
// One list entry at a time
while (previous->os_list_count > 0) {
previous->os_list_count--;
mi_lock_acquire(&previous->subproc->abandoned_os_lock); // this could contend with concurrent OS block abandonment and reclaim from `free`
mi_segment_t* segment = previous->subproc->abandoned_os_list;
// pop from head of the list, a subsequent mark will push at the end (and thus we iterate through os_list_count entries)
if (segment == NULL || mi_arena_segment_os_clear_abandoned(segment, false /* we already have the lock */)) {
mi_lock_release(&previous->subproc->abandoned_os_lock);
return segment;
}
// already abandoned, try again
mi_lock_release(&previous->subproc->abandoned_os_lock);
}
// done
mi_assert_internal(previous->os_list_count == 0);
return NULL;
}
// reclaim abandoned segments
// this does not set the thread id (so it appears as still abandoned)
mi_segment_t* _mi_arena_segment_clear_abandoned_next(mi_arena_field_cursor_t* previous) {
if (previous->start < previous->end) {
// walk the arena
mi_segment_t* segment = mi_arena_segment_clear_abandoned_next_field(previous);
if (segment != NULL) { return segment; }
}
// no entries in the arena's anymore, walk the abandoned OS list
mi_assert_internal(previous->start == previous->end);
return mi_arena_segment_clear_abandoned_next_list(previous);
}
bool mi_abandoned_visit_blocks(mi_subproc_id_t subproc_id, int heap_tag, bool visit_blocks, mi_block_visit_fun* visitor, void* arg) {
// (unfortunately) the visit_abandoned option must be enabled from the start.
// This is to avoid taking locks if abandoned list visiting is not required (as for most programs)
if (!mi_option_is_enabled(mi_option_visit_abandoned)) {
_mi_error_message(EFAULT, "internal error: can only visit abandoned blocks when MIMALLOC_VISIT_ABANDONED=ON");
return false;
}
mi_arena_field_cursor_t current;
_mi_arena_field_cursor_init(NULL, _mi_subproc_from_id(subproc_id), true /* visit all (blocking) */, &current);
mi_segment_t* segment;
bool ok = true;
while (ok && (segment = _mi_arena_segment_clear_abandoned_next(&current)) != NULL) {
ok = _mi_segment_visit_blocks(segment, heap_tag, visit_blocks, visitor, arg);
_mi_arena_segment_mark_abandoned(segment);
}
_mi_arena_field_cursor_done(&current);
return ok;
}

49
src/arena.c
View file

@ -43,7 +43,6 @@ typedef struct mi_arena_s {
bool is_exclusive; // only allow allocations if specifically for this arena
bool is_large; // memory area consists of large- or huge OS pages (always committed)
_Atomic(mi_msecs_t) purge_expire; // expiration time when slices can be purged from `slices_purge`.
_Atomic(mi_msecs_t) purge_expire_extend; // the purge expiration may be extended by a bit
mi_bitmap_t* slices_free; // is the slice free?
mi_bitmap_t* slices_committed; // is the slice committed? (i.e. accessible)
@ -56,14 +55,6 @@ typedef struct mi_arena_s {
// note: when adding bitmaps revise `mi_arena_info_slices_needed`
} mi_arena_t;
// Every "page" in `pages_purge` points to purge info
// (since we use it for any free'd range and not just for pages)
typedef struct mi_purge_info_s {
_Atomic(mi_msecs_t) expire;
_Atomic(size_t) slice_count;
} mi_purge_info_t;
/* -----------------------------------------------------------
Arena id's
@ -1140,7 +1131,6 @@ static bool mi_manage_os_memory_ex2(mi_subproc_t* subproc, void* start, size_t s
arena->numa_node = numa_node; // TODO: or get the current numa node if -1? (now it allows anyone to allocate on -1)
arena->is_large = is_large;
arena->purge_expire = 0;
arena->purge_expire_extend = 0;
// mi_lock_init(&arena->abandoned_visit_lock);
// init bitmaps
@ -1455,14 +1445,15 @@ static void mi_arena_schedule_purge(mi_arena_t* arena, size_t slice_index, size_
}
else {
// schedule purge
const mi_msecs_t expire = _mi_clock_now() + delay;
mi_msecs_t expire0 = 0;
if (mi_atomic_casi64_strong_acq_rel(&arena->purge_expire, &expire0, _mi_clock_now() + delay)) {
if (mi_atomic_casi64_strong_acq_rel(&arena->purge_expire, &expire0, expire)) {
// expiration was not yet set
mi_atomic_storei64_release(&arena->purge_expire_extend, 0);
// maybe set the global arenas expire as well (if it wasn't set already)
mi_atomic_casi64_strong_acq_rel(&arena->subproc->purge_expire, &expire0, expire);
}
else if (mi_atomic_loadi64_acquire(&arena->purge_expire_extend) < 10*delay) { // limit max extension time
else {
// already an expiration was set
mi_atomic_addi64_acq_rel(&arena->purge_expire_extend, (mi_msecs_t)(delay/10)); // add smallish extra delay
}
mi_bitmap_setN(arena->slices_purge, slice_index, slice_count, NULL);
}
@ -1515,18 +1506,13 @@ static bool mi_arena_try_purge(mi_arena_t* arena, mi_msecs_t now, bool force)
{
// check pre-conditions
if (arena->memid.is_pinned) return false;
mi_msecs_t expire_base = mi_atomic_loadi64_relaxed(&arena->purge_expire);
mi_msecs_t expire_extend = mi_atomic_loadi64_relaxed(&arena->purge_expire_extend);
const mi_msecs_t expire = expire_base + expire_extend;
if (expire == 0) return false;
// expired yet?
if (!force && expire > now) return false;
mi_msecs_t expire = mi_atomic_loadi64_relaxed(&arena->purge_expire);
if (!force && (expire == 0 || expire > now)) return false;
// reset expire (if not already set concurrently)
if (mi_atomic_casi64_strong_acq_rel(&arena->purge_expire, &expire_base, (mi_msecs_t)0)) {
mi_atomic_storei64_release(&arena->purge_expire_extend, (mi_msecs_t)0); // and also reset the extend
}
mi_atomic_casi64_strong_acq_rel(&arena->purge_expire, &expire, (mi_msecs_t)0);
mi_subproc_stat_counter_increase(arena->subproc, arena_purges, 1);
// go through all purge info's (with max MI_BFIELD_BITS ranges at a time)
@ -1543,8 +1529,13 @@ static void mi_arenas_try_purge(bool force, bool visit_all)
{
if (_mi_preloading() || mi_arena_purge_delay() <= 0) return; // nothing will be scheduled
// check if any arena needs purging?
mi_tld_t* tld = _mi_tld();
mi_subproc_t* subproc = tld->subproc;
const mi_msecs_t now = _mi_clock_now();
mi_msecs_t arenas_expire = mi_atomic_load_acquire(&subproc->purge_expire);
if (!force && (arenas_expire == 0 || arenas_expire < now)) return;
const size_t max_arena = mi_arenas_get_count(subproc);
if (max_arena == 0) return;
@ -1552,20 +1543,28 @@ static void mi_arenas_try_purge(bool force, bool visit_all)
static mi_atomic_guard_t purge_guard;
mi_atomic_guard(&purge_guard)
{
const mi_msecs_t now = _mi_clock_now();
// increase global expire: at most one purge per delay cycle
mi_atomic_store_release(&subproc->purge_expire, now + mi_arena_purge_delay());
const size_t arena_start = tld->thread_seq % max_arena;
size_t max_purge_count = (visit_all ? max_arena : 1);
size_t max_purge_count = (visit_all ? max_arena : 2);
bool all_visited = true;
for (size_t _i = 0; _i < max_arena; _i++) {
size_t i = _i + arena_start;
if (i >= max_arena) { i -= max_arena; }
mi_arena_t* arena = mi_arena_from_index(subproc,i);
if (arena != NULL) {
if (mi_arena_try_purge(arena, now, force)) {
if (max_purge_count <= 1) break;
if (max_purge_count <= 1) {
all_visited = false;
break;
}
max_purge_count--;
}
}
}
if (all_visited) {
mi_atomic_store_release(&subproc->purge_expire, (mi_msecs_t)0);
}
}
}