circuitpython/py/modgc.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013, 2014 Damien P. George
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "py/mpstate.h"
#include "py/obj.h"
#include "py/gc.h"
#if MICROPY_PY_GC && MICROPY_ENABLE_GC
// collect(): run a garbage collection
STATIC mp_obj_t py_gc_collect(void) {
gc_collect();
#if MICROPY_PY_GC_COLLECT_RETVAL
return MP_OBJ_NEW_SMALL_INT(MP_STATE_MEM(gc_collected));
#else
return mp_const_none;
#endif
}
MP_DEFINE_CONST_FUN_OBJ_0(gc_collect_obj, py_gc_collect);
// disable(): disable the garbage collector
STATIC mp_obj_t gc_disable(void) {
MP_STATE_MEM(gc_auto_collect_enabled) = 0;
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_0(gc_disable_obj, gc_disable);
// enable(): enable the garbage collector
STATIC mp_obj_t gc_enable(void) {
MP_STATE_MEM(gc_auto_collect_enabled) = 1;
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_0(gc_enable_obj, gc_enable);
STATIC mp_obj_t gc_isenabled(void) {
return mp_obj_new_bool(MP_STATE_MEM(gc_auto_collect_enabled));
}
MP_DEFINE_CONST_FUN_OBJ_0(gc_isenabled_obj, gc_isenabled);
// mem_free(): return the number of bytes of available heap RAM
STATIC mp_obj_t gc_mem_free(void) {
gc_info_t info;
gc_info(&info);
#if MICROPY_GC_SPLIT_HEAP_AUTO
// Include max_new_split value here as a more useful heuristic
return MP_OBJ_NEW_SMALL_INT(info.free + info.max_new_split);
#else
return MP_OBJ_NEW_SMALL_INT(info.free);
#endif
}
MP_DEFINE_CONST_FUN_OBJ_0(gc_mem_free_obj, gc_mem_free);
// mem_alloc(): return the number of bytes of heap RAM that are allocated
STATIC mp_obj_t gc_mem_alloc(void) {
gc_info_t info;
gc_info(&info);
return MP_OBJ_NEW_SMALL_INT(info.used);
}
MP_DEFINE_CONST_FUN_OBJ_0(gc_mem_alloc_obj, gc_mem_alloc);
py/gc: Implement GC running by allocation threshold. Currently, MicroPython runs GC when it could not allocate a block of memory, which happens when heap is exhausted. However, that policy can't work well with "inifinity" heaps, e.g. backed by a virtual memory - there will be a lot of swap thrashing long before VM will be exhausted. Instead, in such cases "allocation threshold" policy is used: a GC is run after some number of allocations have been made. Details vary, for example, number or total amount of allocations can be used, threshold may be self-adjusting based on GC outcome, etc. This change implements a simple variant of such policy for MicroPython. Amount of allocated memory so far is used for threshold, to make it useful to typical finite-size, and small, heaps as used with MicroPython ports. And such GC policy is indeed useful for such types of heaps too, as it allows to better control fragmentation. For example, if a threshold is set to half size of heap, then for an application which usually makes big number of small allocations, that will (try to) keep half of heap memory in a nice defragmented state for an occasional large allocation. For an application which doesn't exhibit such behavior, there won't be any visible effects, except for GC running more frequently, which however may affect performance. To address this, the GC threshold is configurable, and by default is off so far. It's configured with gc.threshold(amount_in_bytes) call (can be queries without an argument).
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#if MICROPY_GC_ALLOC_THRESHOLD
STATIC mp_obj_t gc_threshold(size_t n_args, const mp_obj_t *args) {
if (n_args == 0) {
if (MP_STATE_MEM(gc_alloc_threshold) == (size_t)-1) {
return MP_OBJ_NEW_SMALL_INT(-1);
}
return mp_obj_new_int(MP_STATE_MEM(gc_alloc_threshold) * MICROPY_BYTES_PER_GC_BLOCK);
}
mp_int_t val = mp_obj_get_int(args[0]);
if (val < 0) {
MP_STATE_MEM(gc_alloc_threshold) = (size_t)-1;
} else {
MP_STATE_MEM(gc_alloc_threshold) = val / MICROPY_BYTES_PER_GC_BLOCK;
}
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(gc_threshold_obj, 0, 1, gc_threshold);
#endif
STATIC const mp_rom_map_elem_t mp_module_gc_globals_table[] = {
{ MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_gc) },
{ MP_ROM_QSTR(MP_QSTR_collect), MP_ROM_PTR(&gc_collect_obj) },
{ MP_ROM_QSTR(MP_QSTR_disable), MP_ROM_PTR(&gc_disable_obj) },
{ MP_ROM_QSTR(MP_QSTR_enable), MP_ROM_PTR(&gc_enable_obj) },
{ MP_ROM_QSTR(MP_QSTR_isenabled), MP_ROM_PTR(&gc_isenabled_obj) },
{ MP_ROM_QSTR(MP_QSTR_mem_free), MP_ROM_PTR(&gc_mem_free_obj) },
{ MP_ROM_QSTR(MP_QSTR_mem_alloc), MP_ROM_PTR(&gc_mem_alloc_obj) },
py/gc: Implement GC running by allocation threshold. Currently, MicroPython runs GC when it could not allocate a block of memory, which happens when heap is exhausted. However, that policy can't work well with "inifinity" heaps, e.g. backed by a virtual memory - there will be a lot of swap thrashing long before VM will be exhausted. Instead, in such cases "allocation threshold" policy is used: a GC is run after some number of allocations have been made. Details vary, for example, number or total amount of allocations can be used, threshold may be self-adjusting based on GC outcome, etc. This change implements a simple variant of such policy for MicroPython. Amount of allocated memory so far is used for threshold, to make it useful to typical finite-size, and small, heaps as used with MicroPython ports. And such GC policy is indeed useful for such types of heaps too, as it allows to better control fragmentation. For example, if a threshold is set to half size of heap, then for an application which usually makes big number of small allocations, that will (try to) keep half of heap memory in a nice defragmented state for an occasional large allocation. For an application which doesn't exhibit such behavior, there won't be any visible effects, except for GC running more frequently, which however may affect performance. To address this, the GC threshold is configurable, and by default is off so far. It's configured with gc.threshold(amount_in_bytes) call (can be queries without an argument).
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#if MICROPY_GC_ALLOC_THRESHOLD
{ MP_ROM_QSTR(MP_QSTR_threshold), MP_ROM_PTR(&gc_threshold_obj) },
#endif
};
STATIC MP_DEFINE_CONST_DICT(mp_module_gc_globals, mp_module_gc_globals_table);
const mp_obj_module_t mp_module_gc = {
.base = { &mp_type_module },
.globals = (mp_obj_dict_t *)&mp_module_gc_globals,
};
MP_REGISTER_MODULE(MP_QSTR_gc, mp_module_gc);
#endif