https://github.com/JuliaLang/julia
Tip revision: ad290e93e4d10831c1be42cc706babaaeb49c19c authored by Tony Kelman on 07 June 2017, 11:53:30 UTC
Tag v0.6.0-rc3
Tag v0.6.0-rc3
Tip revision: ad290e9
gc.h
// This file is a part of Julia. License is MIT: https://julialang.org/license
/*
allocation and garbage collection
. non-moving, precise mark and sweep collector
. pool-allocates small objects, keeps big objects on a simple list
*/
#ifndef JULIA_GC_H
#define JULIA_GC_H
#include <stdlib.h>
#include <string.h>
#ifndef _MSC_VER
#include <strings.h>
#endif
#include <assert.h>
#include <inttypes.h>
#include "julia.h"
#include "julia_internal.h"
#include "threading.h"
#ifndef _OS_WINDOWS_
#include <sys/mman.h>
#if defined(_OS_DARWIN_) && !defined(MAP_ANONYMOUS)
#define MAP_ANONYMOUS MAP_ANON
#endif
#endif
#ifdef __cplusplus
extern "C" {
#endif
#define GC_PAGE_LG2 14 // log2(size of a page)
#define GC_PAGE_SZ (1 << GC_PAGE_LG2) // 16k
#define GC_PAGE_OFFSET (JL_HEAP_ALIGNMENT - (sizeof(jl_taggedvalue_t) % JL_HEAP_ALIGNMENT))
#define jl_malloc_tag ((void*)0xdeadaa01)
#define jl_singleton_tag ((void*)0xdeadaa02)
// Used by GC_DEBUG_ENV
typedef struct {
uint64_t num;
uint64_t next;
uint64_t min;
uint64_t interv;
uint64_t max;
unsigned short random[3];
} jl_alloc_num_t;
typedef struct {
int always_full;
int wait_for_debugger;
jl_alloc_num_t pool;
jl_alloc_num_t other;
jl_alloc_num_t print;
} jl_gc_debug_env_t;
// This struct must be kept in sync with the Julia type of the same name in base/util.jl
typedef struct {
int64_t allocd;
int64_t deferred_alloc;
int64_t freed;
uint64_t malloc;
uint64_t realloc;
uint64_t poolalloc;
uint64_t bigalloc;
uint64_t freecall;
uint64_t total_time;
uint64_t total_allocd;
uint64_t since_sweep;
size_t interval;
int pause;
int full_sweep;
} jl_gc_num_t;
// layout for big (>2k) objects
typedef struct _bigval_t {
struct _bigval_t *next;
struct _bigval_t **prev; // pointer to the next field of the prev entry
union {
size_t sz;
uintptr_t age : 2;
};
#ifdef _P64 // Add padding so that the value is 64-byte aligned
// (8 pointers of 8 bytes each) - (4 other pointers in struct)
void *_padding[8 - 4];
#else
// (16 pointers of 4 bytes each) - (4 other pointers in struct)
void *_padding[16 - 4];
#endif
//struct jl_taggedvalue_t <>;
union {
uintptr_t header;
struct {
uintptr_t gc:2;
} bits;
};
// must be 64-byte aligned here, in 32 & 64 bit modes
} bigval_t;
// data structure for tracking malloc'd arrays.
typedef struct _mallocarray_t {
jl_array_t *a;
struct _mallocarray_t *next;
} mallocarray_t;
// pool page metadata
typedef struct {
// index of pool that owns this page
uint8_t pool_n;
// Whether any cell in the page is marked
// This bit is set before sweeping iff there are live cells in the page.
// Note that before marking or after sweeping there can be live
// (and young) cells in the page for `!has_marked`.
uint8_t has_marked;
// Whether any cell was live and young **before sweeping**.
// For a normal sweep (quick sweep that is NOT preceded by a
// full sweep) this bit is set iff there are young or newly dead
// objects in the page and the page needs to be swept.
//
// For a full sweep, this bit should be ignored.
//
// For a quick sweep preceded by a full sweep. If this bit is set,
// the page needs to be swept. If this bit is not set, there could
// still be old dead objects in the page and `nold` and `prev_nold`
// should be used to determine if the page needs to be swept.
uint8_t has_young;
// number of old objects in this page
uint16_t nold;
// number of old objects in this page during the previous full sweep
uint16_t prev_nold;
// number of free objects in this page.
// invalid if pool that owns this page is allocating objects from this page.
uint16_t nfree;
uint16_t osize; // size of each object in this page
uint16_t fl_begin_offset; // offset of first free object in this page
uint16_t fl_end_offset; // offset of last free object in this page
uint16_t thread_n; // thread id of the heap that owns this page
char *data;
uint8_t *ages;
} jl_gc_pagemeta_t;
// Page layout:
// Newpage freelist: sizeof(void*)
// Padding: GC_PAGE_OFFSET - sizeof(void*)
// Blocks: osize * n
// Tag: sizeof(jl_taggedvalue_t)
// Data: <= osize - sizeof(jl_taggedvalue_t)
// Memory map:
// The complete address space is divided up into a multi-level page table.
// The three levels have similar but slightly different structures:
// - pagetable0_t: the bottom/leaf level (covers the contiguous addresses)
// - pagetable1_t: the middle level
// - pagetable2_t: the top/leaf level (covers the entire virtual address space)
// Corresponding to these similar structures is a large amount of repetitive
// code that is nearly the same but not identical. It could be made less
// repetitive with C macros, but only at the cost of debuggability. The specialized
// structure of this representation allows us to partially unroll and optimize
// various conditions at each level.
// The following constants define the branching factors at each level.
// The constants and GC_PAGE_LG2 must therefore sum to sizeof(void*).
// They should all be multiples of 32 (sizeof(uint32_t)) except that REGION2_PG_COUNT may also be 1.
#ifdef _P64
#define REGION0_PG_COUNT (1 << 16)
#define REGION1_PG_COUNT (1 << 16)
#define REGION2_PG_COUNT (1 << 18)
#define REGION0_INDEX(p) (((uintptr_t)(p) >> 14) & 0xFFFF) // shift by GC_PAGE_LG2
#define REGION1_INDEX(p) (((uintptr_t)(p) >> 30) & 0xFFFF)
#define REGION_INDEX(p) (((uintptr_t)(p) >> 46) & 0x3FFFF)
#else
#define REGION0_PG_COUNT (1 << 8)
#define REGION1_PG_COUNT (1 << 10)
#define REGION2_PG_COUNT (1 << 0)
#define REGION0_INDEX(p) (((uintptr_t)(p) >> 14) & 0xFF) // shift by GC_PAGE_LG2
#define REGION1_INDEX(p) (((uintptr_t)(p) >> 22) & 0x3FF)
#define REGION_INDEX(p) (0)
#endif
// define the representation of the levels of the page-table (0 to 2)
typedef struct {
jl_gc_pagemeta_t *meta[REGION0_PG_COUNT];
uint32_t allocmap[REGION0_PG_COUNT / 32];
uint32_t freemap[REGION0_PG_COUNT / 32];
// store a lower bound of the first free page in each region
int lb;
// an upper bound of the last non-free page
int ub;
} pagetable0_t;
typedef struct {
pagetable0_t *meta0[REGION1_PG_COUNT];
uint32_t allocmap0[REGION1_PG_COUNT / 32];
uint32_t freemap0[REGION1_PG_COUNT / 32];
// store a lower bound of the first free page in each region
int lb;
// an upper bound of the last non-free page
int ub;
} pagetable1_t;
typedef struct {
pagetable1_t *meta1[REGION2_PG_COUNT];
uint32_t allocmap1[(REGION2_PG_COUNT + 31) / 32];
uint32_t freemap1[(REGION2_PG_COUNT + 31) / 32];
// store a lower bound of the first free page in each region
int lb;
// an upper bound of the last non-free page
int ub;
} pagetable_t;
STATIC_INLINE unsigned ffs_u32(uint32_t bitvec)
{
#if defined(_COMPILER_MINGW_)
return __builtin_ffs(bitvec) - 1;
#elif defined(_COMPILER_MICROSOFT_)
unsigned long j;
_BitScanForward(&j, bitvec);
return j;
#else
return ffs(bitvec) - 1;
#endif
}
extern jl_gc_num_t gc_num;
extern pagetable_t memory_map;
extern bigval_t *big_objects_marked;
extern arraylist_t finalizer_list_marked;
extern arraylist_t to_finalize;
extern int64_t lazy_freed_pages;
STATIC_INLINE bigval_t *bigval_header(jl_taggedvalue_t *o)
{
return container_of(o, bigval_t, header);
}
// round an address inside a gcpage's data to its beginning
STATIC_INLINE char *gc_page_data(void *x)
{
return (char*)(((uintptr_t)x >> GC_PAGE_LG2) << GC_PAGE_LG2);
}
STATIC_INLINE jl_taggedvalue_t *page_pfl_beg(jl_gc_pagemeta_t *p)
{
return (jl_taggedvalue_t*)(p->data + p->fl_begin_offset);
}
STATIC_INLINE jl_taggedvalue_t *page_pfl_end(jl_gc_pagemeta_t *p)
{
return (jl_taggedvalue_t*)(p->data + p->fl_end_offset);
}
STATIC_INLINE int gc_marked(uintptr_t bits)
{
return (bits & GC_MARKED) != 0;
}
STATIC_INLINE int gc_old(uintptr_t bits)
{
return (bits & GC_OLD) != 0;
}
STATIC_INLINE uintptr_t gc_set_bits(uintptr_t tag, int bits)
{
return (tag & ~(uintptr_t)3) | bits;
}
STATIC_INLINE uintptr_t gc_ptr_tag(void *v, uintptr_t mask)
{
return ((uintptr_t)v) & mask;
}
STATIC_INLINE void *gc_ptr_clear_tag(void *v, uintptr_t mask)
{
return (void*)(((uintptr_t)v) & ~mask);
}
NOINLINE uintptr_t gc_get_stack_ptr(void);
STATIC_INLINE jl_gc_pagemeta_t *page_metadata(void *_data)
{
uintptr_t data = ((uintptr_t)_data);
unsigned i;
i = REGION_INDEX(data);
pagetable1_t *r1 = memory_map.meta1[i];
if (!r1)
return NULL;
i = REGION1_INDEX(data);
pagetable0_t *r0 = r1->meta0[i];
if (!r0)
return NULL;
i = REGION0_INDEX(data);
return r0->meta[i];
}
struct jl_gc_metadata_ext {
pagetable1_t *pagetable1;
pagetable0_t *pagetable0;
jl_gc_pagemeta_t *meta;
unsigned pagetable_i32, pagetable_i;
unsigned pagetable1_i32, pagetable1_i;
unsigned pagetable0_i32, pagetable0_i;
};
STATIC_INLINE struct jl_gc_metadata_ext page_metadata_ext(void *_data)
{
uintptr_t data = (uintptr_t)_data;
struct jl_gc_metadata_ext info;
unsigned i;
i = REGION_INDEX(data);
info.pagetable_i = i % 32;
info.pagetable_i32 = i / 32;
info.pagetable1 = memory_map.meta1[i];
i = REGION1_INDEX(data);
info.pagetable1_i = i % 32;
info.pagetable1_i32 = i / 32;
info.pagetable0 = info.pagetable1->meta0[i];
i = REGION0_INDEX(data);
info.pagetable0_i = i % 32;
info.pagetable0_i32 = i / 32;
info.meta = info.pagetable0->meta[i];
assert(info.meta);
return info;
}
STATIC_INLINE void gc_big_object_unlink(const bigval_t *hdr)
{
*hdr->prev = hdr->next;
if (hdr->next) {
hdr->next->prev = hdr->prev;
}
}
STATIC_INLINE void gc_big_object_link(bigval_t *hdr, bigval_t **list)
{
hdr->next = *list;
hdr->prev = list;
if (*list)
(*list)->prev = &hdr->next;
*list = hdr;
}
void mark_all_roots(jl_ptls_t ptls);
void gc_mark_object_list(jl_ptls_t ptls, arraylist_t *list, size_t start);
void visit_mark_stack(jl_ptls_t ptls);
void gc_debug_init(void);
void jl_mark_box_caches(jl_ptls_t ptls);
// GC pages
void jl_gc_init_page(void);
NOINLINE jl_gc_pagemeta_t *jl_gc_alloc_page(void);
void jl_gc_free_page(void *p);
// GC debug
#if defined(GC_TIME) || defined(GC_FINAL_STATS)
void gc_settime_premark_end(void);
void gc_settime_postmark_end(void);
#else
#define gc_settime_premark_end()
#define gc_settime_postmark_end()
#endif
#ifdef GC_FINAL_STATS
void gc_final_count_page(size_t pg_cnt);
void gc_final_pause_end(int64_t t0, int64_t tend);
#else
#define gc_final_count_page(pg_cnt)
#define gc_final_pause_end(t0, tend)
#endif
#ifdef GC_TIME
void gc_time_pool_start(void);
void gc_time_count_page(int freedall, int pg_skpd);
void gc_time_pool_end(int sweep_full);
void gc_time_big_start(void);
void gc_time_count_big(int old_bits, int bits);
void gc_time_big_end(void);
void gc_time_mallocd_array_start(void);
void gc_time_count_mallocd_array(int bits);
void gc_time_mallocd_array_end(void);
void gc_time_mark_pause(int64_t t0, int64_t scanned_bytes,
int64_t perm_scanned_bytes);
void gc_time_sweep_pause(uint64_t gc_end_t, int64_t actual_allocd,
int64_t live_bytes, int64_t estimate_freed,
int sweep_full);
#else
#define gc_time_pool_start()
STATIC_INLINE void gc_time_count_page(int freedall, int pg_skpd)
{
(void)freedall;
(void)pg_skpd;
}
#define gc_time_pool_end(sweep_full)
#define gc_time_big_start()
STATIC_INLINE void gc_time_count_big(int old_bits, int bits)
{
(void)old_bits;
(void)bits;
}
#define gc_time_big_end()
#define gc_time_mallocd_array_start()
STATIC_INLINE void gc_time_count_mallocd_array(int bits)
{
(void)bits;
}
#define gc_time_mallocd_array_end()
#define gc_time_mark_pause(t0, scanned_bytes, perm_scanned_bytes)
#define gc_time_sweep_pause(gc_end_t, actual_allocd, live_bytes, \
estimate_freed, sweep_full)
#endif
#ifdef MEMFENCE
void gc_verify_tags(void);
#else
static inline void gc_verify_tags(void)
{
}
#endif
#ifdef GC_VERIFY
extern jl_value_t *lostval;
void gc_verify(jl_ptls_t ptls);
void add_lostval_parent(jl_value_t *parent);
#define verify_val(v) do { \
if (lostval == (jl_value_t*)(v) && (v) != 0) { \
jl_printf(JL_STDOUT, \
"Found lostval %p at %s:%d oftype: ", \
(void*)(lostval), __FILE__, __LINE__); \
jl_static_show(JL_STDOUT, jl_typeof(v)); \
jl_printf(JL_STDOUT, "\n"); \
} \
} while(0);
#define verify_parent(ty, obj, slot, args...) do { \
if (gc_ptr_clear_tag(*(void**)(slot), 3) == (void*)lostval && \
(jl_value_t*)(obj) != lostval) { \
jl_printf(JL_STDOUT, "Found parent %p %p at %s:%d\n", \
(void*)(ty), (void*)(obj), __FILE__, __LINE__); \
jl_printf(JL_STDOUT, "\tloc %p : ", (void*)(slot)); \
jl_printf(JL_STDOUT, args); \
jl_printf(JL_STDOUT, "\n"); \
jl_printf(JL_STDOUT, "\ttype: "); \
jl_static_show(JL_STDOUT, jl_typeof(obj)); \
jl_printf(JL_STDOUT, "\n"); \
add_lostval_parent((jl_value_t*)(obj)); \
} \
} while(0);
#define verify_parent1(ty,obj,slot,arg1) verify_parent(ty,obj,slot,arg1)
#define verify_parent2(ty,obj,slot,arg1,arg2) verify_parent(ty,obj,slot,arg1,arg2)
extern int gc_verifying;
#else
#define gc_verify(ptls)
#define verify_val(v)
#define verify_parent1(ty,obj,slot,arg1)
#define verify_parent2(ty,obj,slot,arg1,arg2)
#define gc_verifying (0)
#endif
#ifdef GC_DEBUG_ENV
JL_DLLEXPORT extern jl_gc_debug_env_t jl_gc_debug_env;
#define gc_sweep_always_full jl_gc_debug_env.always_full
int gc_debug_check_other(void);
int gc_debug_check_pool(void);
void gc_debug_print(void);
void gc_scrub_record_task(jl_task_t *ta);
void gc_scrub(void);
#else
#define gc_sweep_always_full 0
static inline int gc_debug_check_other(void)
{
return 0;
}
static inline int gc_debug_check_pool(void)
{
return 0;
}
static inline void gc_debug_print(void)
{
}
static inline void gc_scrub_record_task(jl_task_t *ta)
{
(void)ta;
}
static inline void gc_scrub(void)
{
}
#endif
#ifdef OBJPROFILE
void objprofile_count(void *ty, int old, int sz);
void objprofile_printall(void);
void objprofile_reset(void);
#else
static inline void objprofile_count(void *ty, int old, int sz)
{
}
static inline void objprofile_printall(void)
{
}
static inline void objprofile_reset(void)
{
}
#endif
#ifdef MEMPROFILE
void gc_stats_all_pool(void);
void gc_stats_big_obj(void);
#else
#define gc_stats_all_pool()
#define gc_stats_big_obj()
#endif
// For debugging
void gc_count_pool(void);
#ifdef __cplusplus
}
#endif
#endif