PostgreSQL Source Code  git master
dsa.c File Reference
#include "postgres.h"
#include "port/atomics.h"
#include "port/pg_bitutils.h"
#include "storage/dsm.h"
#include "storage/lwlock.h"
#include "utils/dsa.h"
#include "utils/freepage.h"
#include "utils/memutils.h"
#include "utils/resowner.h"
Include dependency graph for dsa.c:

Go to the source code of this file.

Data Structures

struct  dsa_segment_header
 
struct  dsa_area_span
 
struct  dsa_area_pool
 
struct  dsa_area_control
 
struct  dsa_segment_map
 
struct  dsa_area
 

Macros

#define DSA_INITIAL_SEGMENT_SIZE   ((size_t) (1 * 1024 * 1024))
 
#define DSA_NUM_SEGMENTS_AT_EACH_SIZE   2
 
#define DSA_OFFSET_WIDTH   40 /* 1024 segments of size up to 1TB */
 
#define DSA_MAX_SEGMENTS    Min(1024, (1 << ((SIZEOF_DSA_POINTER * 8) - DSA_OFFSET_WIDTH)))
 
#define DSA_OFFSET_BITMASK   (((dsa_pointer) 1 << DSA_OFFSET_WIDTH) - 1)
 
#define DSA_MAX_SEGMENT_SIZE   ((size_t) 1 << DSA_OFFSET_WIDTH)
 
#define DSA_PAGES_PER_SUPERBLOCK   16
 
#define DSA_SEGMENT_HEADER_MAGIC   0x0ce26608
 
#define DSA_MAKE_POINTER(segment_number, offset)    (((dsa_pointer) (segment_number) << DSA_OFFSET_WIDTH) | (offset))
 
#define DSA_EXTRACT_SEGMENT_NUMBER(dp)   ((dp) >> DSA_OFFSET_WIDTH)
 
#define DSA_EXTRACT_OFFSET(dp)   ((dp) & DSA_OFFSET_BITMASK)
 
#define DSA_SEGMENT_INDEX_NONE   (~(dsa_segment_index)0)
 
#define DSA_NUM_SEGMENT_BINS   16
 
#define DSA_AREA_LOCK(area)   (&area->control->lock)
 
#define DSA_SCLASS_LOCK(area, sclass)   (&area->control->pools[sclass].lock)
 
#define NextFreeObjectIndex(object)   (* (uint16 *) (object))
 
#define DSA_NUM_SIZE_CLASSES   lengthof(dsa_size_classes)
 
#define DSA_SCLASS_BLOCK_OF_SPANS   0
 
#define DSA_SCLASS_SPAN_LARGE   1
 
#define DSA_SIZE_CLASS_MAP_QUANTUM   8
 
#define DSA_FULLNESS_CLASSES   4
 
#define DsaAreaPoolToDsaPointer(area, p)    DSA_MAKE_POINTER(0, (char *) p - (char *) area->control)
 
#define DSA_SPAN_NOTHING_FREE   ((uint16) -1)
 
#define DSA_SUPERBLOCK_SIZE   (DSA_PAGES_PER_SUPERBLOCK * FPM_PAGE_SIZE)
 
#define get_segment_index(area, segment_map_ptr)    (segment_map_ptr - &area->segment_maps[0])
 

Typedefs

typedef size_t dsa_segment_index
 

Functions

static size_t contiguous_pages_to_segment_bin (size_t n)
 
static void init_span (dsa_area *area, dsa_pointer span_pointer, dsa_area_pool *pool, dsa_pointer start, size_t npages, uint16 size_class)
 
static bool transfer_first_span (dsa_area *area, dsa_area_pool *pool, int fromclass, int toclass)
 
static dsa_pointer alloc_object (dsa_area *area, int size_class)
 
static bool ensure_active_superblock (dsa_area *area, dsa_area_pool *pool, int size_class)
 
static dsa_segment_mapget_segment_by_index (dsa_area *area, dsa_segment_index index)
 
static void destroy_superblock (dsa_area *area, dsa_pointer span_pointer)
 
static void unlink_span (dsa_area *area, dsa_area_span *span)
 
static void add_span_to_fullness_class (dsa_area *area, dsa_area_span *span, dsa_pointer span_pointer, int fclass)
 
static void unlink_segment (dsa_area *area, dsa_segment_map *segment_map)
 
static dsa_segment_mapget_best_segment (dsa_area *area, size_t npages)
 
static dsa_segment_mapmake_new_segment (dsa_area *area, size_t requested_pages)
 
static dsa_areacreate_internal (void *place, size_t size, int tranche_id, dsm_handle control_handle, dsm_segment *control_segment)
 
static dsa_areaattach_internal (void *place, dsm_segment *segment, dsa_handle handle)
 
static void check_for_freed_segments (dsa_area *area)
 
static void check_for_freed_segments_locked (dsa_area *area)
 
static void rebin_segment (dsa_area *area, dsa_segment_map *segment_map)
 
dsa_areadsa_create (int tranche_id)
 
dsa_areadsa_create_in_place (void *place, size_t size, int tranche_id, dsm_segment *segment)
 
dsa_handle dsa_get_handle (dsa_area *area)
 
dsa_areadsa_attach (dsa_handle handle)
 
dsa_areadsa_attach_in_place (void *place, dsm_segment *segment)
 
void dsa_on_dsm_detach_release_in_place (dsm_segment *segment, Datum place)
 
void dsa_on_shmem_exit_release_in_place (int code, Datum place)
 
void dsa_release_in_place (void *place)
 
void dsa_pin_mapping (dsa_area *area)
 
dsa_pointer dsa_allocate_extended (dsa_area *area, size_t size, int flags)
 
void dsa_free (dsa_area *area, dsa_pointer dp)
 
void * dsa_get_address (dsa_area *area, dsa_pointer dp)
 
void dsa_pin (dsa_area *area)
 
void dsa_unpin (dsa_area *area)
 
void dsa_set_size_limit (dsa_area *area, size_t limit)
 
size_t dsa_get_total_size (dsa_area *area)
 
void dsa_trim (dsa_area *area)
 
void dsa_dump (dsa_area *area)
 
size_t dsa_minimum_size (void)
 
void dsa_detach (dsa_area *area)
 

Variables

static const uint16 dsa_size_classes []
 
static const uint8 dsa_size_class_map []
 

Macro Definition Documentation

◆ DSA_AREA_LOCK

#define DSA_AREA_LOCK (   area)    (&area->control->lock)

Definition at line 154 of file dsa.c.

◆ DSA_EXTRACT_OFFSET

#define DSA_EXTRACT_OFFSET (   dp)    ((dp) & DSA_OFFSET_BITMASK)

Definition at line 121 of file dsa.c.

◆ DSA_EXTRACT_SEGMENT_NUMBER

#define DSA_EXTRACT_SEGMENT_NUMBER (   dp)    ((dp) >> DSA_OFFSET_WIDTH)

Definition at line 118 of file dsa.c.

◆ DSA_FULLNESS_CLASSES

#define DSA_FULLNESS_CLASSES   4

Definition at line 288 of file dsa.c.

◆ DSA_INITIAL_SEGMENT_SIZE

#define DSA_INITIAL_SEGMENT_SIZE   ((size_t) (1 * 1024 * 1024))

Definition at line 68 of file dsa.c.

◆ DSA_MAKE_POINTER

#define DSA_MAKE_POINTER (   segment_number,
  offset 
)     (((dsa_pointer) (segment_number) << DSA_OFFSET_WIDTH) | (offset))

Definition at line 114 of file dsa.c.

◆ DSA_MAX_SEGMENT_SIZE

#define DSA_MAX_SEGMENT_SIZE   ((size_t) 1 << DSA_OFFSET_WIDTH)

Definition at line 101 of file dsa.c.

◆ DSA_MAX_SEGMENTS

#define DSA_MAX_SEGMENTS    Min(1024, (1 << ((SIZEOF_DSA_POINTER * 8) - DSA_OFFSET_WIDTH)))

Definition at line 94 of file dsa.c.

◆ DSA_NUM_SEGMENT_BINS

#define DSA_NUM_SEGMENT_BINS   16

Definition at line 133 of file dsa.c.

◆ DSA_NUM_SEGMENTS_AT_EACH_SIZE

#define DSA_NUM_SEGMENTS_AT_EACH_SIZE   2

Definition at line 77 of file dsa.c.

◆ DSA_NUM_SIZE_CLASSES

#define DSA_NUM_SIZE_CLASSES   lengthof(dsa_size_classes)

Definition at line 258 of file dsa.c.

◆ DSA_OFFSET_BITMASK

#define DSA_OFFSET_BITMASK   (((dsa_pointer) 1 << DSA_OFFSET_WIDTH) - 1)

Definition at line 98 of file dsa.c.

◆ DSA_OFFSET_WIDTH

#define DSA_OFFSET_WIDTH   40 /* 1024 segments of size up to 1TB */

Definition at line 87 of file dsa.c.

◆ DSA_PAGES_PER_SUPERBLOCK

#define DSA_PAGES_PER_SUPERBLOCK   16

Definition at line 104 of file dsa.c.

◆ DSA_SCLASS_BLOCK_OF_SPANS

#define DSA_SCLASS_BLOCK_OF_SPANS   0

Definition at line 261 of file dsa.c.

◆ DSA_SCLASS_LOCK

#define DSA_SCLASS_LOCK (   area,
  sclass 
)    (&area->control->pools[sclass].lock)

Definition at line 155 of file dsa.c.

◆ DSA_SCLASS_SPAN_LARGE

#define DSA_SCLASS_SPAN_LARGE   1

Definition at line 262 of file dsa.c.

◆ DSA_SEGMENT_HEADER_MAGIC

#define DSA_SEGMENT_HEADER_MAGIC   0x0ce26608

Definition at line 111 of file dsa.c.

◆ DSA_SEGMENT_INDEX_NONE

#define DSA_SEGMENT_INDEX_NONE   (~(dsa_segment_index)0)

Definition at line 127 of file dsa.c.

◆ DSA_SIZE_CLASS_MAP_QUANTUM

#define DSA_SIZE_CLASS_MAP_QUANTUM   8

Definition at line 280 of file dsa.c.

◆ DSA_SPAN_NOTHING_FREE

#define DSA_SPAN_NOTHING_FREE   ((uint16) -1)

Definition at line 393 of file dsa.c.

◆ DSA_SUPERBLOCK_SIZE

#define DSA_SUPERBLOCK_SIZE   (DSA_PAGES_PER_SUPERBLOCK * FPM_PAGE_SIZE)

Definition at line 394 of file dsa.c.

◆ DsaAreaPoolToDsaPointer

#define DsaAreaPoolToDsaPointer (   area,
 
)     DSA_MAKE_POINTER(0, (char *) p - (char *) area->control)

Definition at line 340 of file dsa.c.

◆ get_segment_index

#define get_segment_index (   area,
  segment_map_ptr 
)     (segment_map_ptr - &area->segment_maps[0])

Definition at line 397 of file dsa.c.

◆ NextFreeObjectIndex

#define NextFreeObjectIndex (   object)    (* (uint16 *) (object))

Definition at line 224 of file dsa.c.

Typedef Documentation

◆ dsa_segment_index

typedef size_t dsa_segment_index

Definition at line 124 of file dsa.c.

Function Documentation

◆ add_span_to_fullness_class()

static void add_span_to_fullness_class ( dsa_area area,
dsa_area_span span,
dsa_pointer  span_pointer,
int  fclass 
)
static

Definition at line 1934 of file dsa.c.

1937 {
1938  dsa_area_pool *pool = dsa_get_address(area, span->pool);
1939 
1940  if (DsaPointerIsValid(pool->spans[fclass]))
1941  {
1942  dsa_area_span *head = dsa_get_address(area,
1943  pool->spans[fclass]);
1944 
1945  head->prevspan = span_pointer;
1946  }
1947  span->prevspan = InvalidDsaPointer;
1948  span->nextspan = pool->spans[fclass];
1949  pool->spans[fclass] = span_pointer;
1950  span->fclass = fclass;
1951 }
void * dsa_get_address(dsa_area *area, dsa_pointer dp)
Definition: dsa.c:955
#define InvalidDsaPointer
Definition: dsa.h:78
#define DsaPointerIsValid(x)
Definition: dsa.h:81
dsa_pointer spans[DSA_FULLNESS_CLASSES]
Definition: dsa.c:301
dsa_pointer nextspan
Definition: dsa.c:209
uint16 fclass
Definition: dsa.c:217
dsa_pointer prevspan
Definition: dsa.c:208
dsa_pointer pool
Definition: dsa.c:207

References dsa_get_address(), DsaPointerIsValid, dsa_area_span::fclass, InvalidDsaPointer, dsa_area_span::nextspan, dsa_area_span::pool, dsa_area_span::prevspan, and dsa_area_pool::spans.

Referenced by dsa_free().

◆ alloc_object()

static dsa_pointer alloc_object ( dsa_area area,
int  size_class 
)
inlinestatic

Definition at line 1477 of file dsa.c.

1478 {
1479  dsa_area_pool *pool = &area->control->pools[size_class];
1480  dsa_area_span *span;
1481  dsa_pointer block;
1482  dsa_pointer result;
1483  char *object;
1484  size_t size;
1485 
1486  /*
1487  * Even though ensure_active_superblock can in turn call alloc_object if
1488  * it needs to allocate a new span, that's always from a different pool,
1489  * and the order of lock acquisition is always the same, so it's OK that
1490  * we hold this lock for the duration of this function.
1491  */
1492  Assert(!LWLockHeldByMe(DSA_SCLASS_LOCK(area, size_class)));
1493  LWLockAcquire(DSA_SCLASS_LOCK(area, size_class), LW_EXCLUSIVE);
1494 
1495  /*
1496  * If there's no active superblock, we must successfully obtain one or
1497  * fail the request.
1498  */
1499  if (!DsaPointerIsValid(pool->spans[1]) &&
1500  !ensure_active_superblock(area, pool, size_class))
1501  {
1502  result = InvalidDsaPointer;
1503  }
1504  else
1505  {
1506  /*
1507  * There should be a block in fullness class 1 at this point, and it
1508  * should never be completely full. Thus we can either pop an object
1509  * from the free list or, failing that, initialize a new object.
1510  */
1511  Assert(DsaPointerIsValid(pool->spans[1]));
1512  span = (dsa_area_span *)
1513  dsa_get_address(area, pool->spans[1]);
1514  Assert(span->nallocatable > 0);
1515  block = span->start;
1516  Assert(size_class < DSA_NUM_SIZE_CLASSES);
1517  size = dsa_size_classes[size_class];
1518  if (span->firstfree != DSA_SPAN_NOTHING_FREE)
1519  {
1520  result = block + span->firstfree * size;
1521  object = dsa_get_address(area, result);
1522  span->firstfree = NextFreeObjectIndex(object);
1523  }
1524  else
1525  {
1526  result = block + span->ninitialized * size;
1527  ++span->ninitialized;
1528  }
1529  --span->nallocatable;
1530 
1531  /* If it's now full, move it to the highest-numbered fullness class. */
1532  if (span->nallocatable == 0)
1533  transfer_first_span(area, pool, 1, DSA_FULLNESS_CLASSES - 1);
1534  }
1535 
1536  Assert(LWLockHeldByMe(DSA_SCLASS_LOCK(area, size_class)));
1537  LWLockRelease(DSA_SCLASS_LOCK(area, size_class));
1538 
1539  return result;
1540 }
static const uint16 dsa_size_classes[]
Definition: dsa.c:247
static bool ensure_active_superblock(dsa_area *area, dsa_area_pool *pool, int size_class)
Definition: dsa.c:1565
#define DSA_SPAN_NOTHING_FREE
Definition: dsa.c:393
#define DSA_SCLASS_LOCK(area, sclass)
Definition: dsa.c:155
static bool transfer_first_span(dsa_area *area, dsa_area_pool *pool, int fromclass, int toclass)
Definition: dsa.c:1437
#define DSA_NUM_SIZE_CLASSES
Definition: dsa.c:258
#define NextFreeObjectIndex(object)
Definition: dsa.c:224
#define DSA_FULLNESS_CLASSES
Definition: dsa.c:288
uint64 dsa_pointer
Definition: dsa.h:62
Assert(fmt[strlen(fmt) - 1] !='\n')
bool LWLockHeldByMe(LWLock *lock)
Definition: lwlock.c:1897
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1172
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1785
@ LW_EXCLUSIVE
Definition: lwlock.h:116
static pg_noinline void Size size
Definition: slab.c:607
dsa_area_pool pools[DSA_NUM_SIZE_CLASSES]
Definition: dsa.c:320
dsa_pointer start
Definition: dsa.c:210
uint16 nallocatable
Definition: dsa.c:214
uint16 ninitialized
Definition: dsa.c:213
uint16 firstfree
Definition: dsa.c:215
dsa_area_control * control
Definition: dsa.c:368

References Assert(), dsa_area::control, DSA_FULLNESS_CLASSES, dsa_get_address(), DSA_NUM_SIZE_CLASSES, DSA_SCLASS_LOCK, dsa_size_classes, DSA_SPAN_NOTHING_FREE, DsaPointerIsValid, ensure_active_superblock(), dsa_area_span::firstfree, InvalidDsaPointer, LW_EXCLUSIVE, LWLockAcquire(), LWLockHeldByMe(), LWLockRelease(), dsa_area_span::nallocatable, NextFreeObjectIndex, dsa_area_span::ninitialized, dsa_area_control::pools, size, dsa_area_pool::spans, dsa_area_span::start, and transfer_first_span().

Referenced by dsa_allocate_extended(), and ensure_active_superblock().

◆ attach_internal()

static dsa_area * attach_internal ( void *  place,
dsm_segment segment,
dsa_handle  handle 
)
static

Definition at line 1331 of file dsa.c.

1332 {
1333  dsa_area_control *control;
1334  dsa_area *area;
1335  dsa_segment_map *segment_map;
1336 
1337  control = (dsa_area_control *) place;
1338  Assert(control->handle == handle);
1339  Assert(control->segment_handles[0] == handle);
1340  Assert(control->segment_header.magic ==
1341  (DSA_SEGMENT_HEADER_MAGIC ^ handle ^ 0));
1342 
1343  /* Build the backend-local area object. */
1344  area = palloc(sizeof(dsa_area));
1345  area->control = control;
1347  memset(&area->segment_maps[0], 0,
1348  sizeof(dsa_segment_map) * DSA_MAX_SEGMENTS);
1349  area->high_segment_index = 0;
1350 
1351  /* Set up the segment map for this process's mapping. */
1352  segment_map = &area->segment_maps[0];
1353  segment_map->segment = segment; /* NULL for in-place */
1354  segment_map->mapped_address = place;
1355  segment_map->header = (dsa_segment_header *) segment_map->mapped_address;
1356  segment_map->fpm = (FreePageManager *)
1357  (segment_map->mapped_address + MAXALIGN(sizeof(dsa_area_control)));
1358  segment_map->pagemap = (dsa_pointer *)
1359  (segment_map->mapped_address + MAXALIGN(sizeof(dsa_area_control)) +
1360  MAXALIGN(sizeof(FreePageManager)));
1361 
1362  /* Bump the reference count. */
1364  if (control->refcnt == 0)
1365  {
1366  /* We can't attach to a DSA area that has already been destroyed. */
1367  ereport(ERROR,
1368  (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
1369  errmsg("could not attach to dynamic shared area")));
1370  }
1371  ++control->refcnt;
1374 
1375  return area;
1376 }
#define MAXALIGN(LEN)
Definition: c.h:798
#define DSA_AREA_LOCK(area)
Definition: dsa.c:154
#define DSA_SEGMENT_HEADER_MAGIC
Definition: dsa.c:111
#define DSA_MAX_SEGMENTS
Definition: dsa.c:94
int errcode(int sqlerrcode)
Definition: elog.c:859
int errmsg(const char *fmt,...)
Definition: elog.c:1072
#define ERROR
Definition: elog.h:39
#define ereport(elevel,...)
Definition: elog.h:149
void * palloc(Size size)
Definition: mcxt.c:1304
ResourceOwner CurrentResourceOwner
Definition: resowner.c:165
dsa_segment_header segment_header
Definition: dsa.c:312
size_t freed_segment_counter
Definition: dsa.c:332
int refcnt
Definition: dsa.c:328
dsa_handle handle
Definition: dsa.c:314
dsm_handle segment_handles[DSA_MAX_SEGMENTS]
Definition: dsa.c:316
Definition: dsa.c:366
dsa_segment_map segment_maps[DSA_MAX_SEGMENTS]
Definition: dsa.c:384
dsa_segment_index high_segment_index
Definition: dsa.c:387
size_t freed_segment_counter
Definition: dsa.c:390
ResourceOwner resowner
Definition: dsa.c:376
uint32 magic
Definition: dsa.c:165
dsa_segment_header * header
Definition: dsa.c:354
FreePageManager * fpm
Definition: dsa.c:355
dsm_segment * segment
Definition: dsa.c:352
dsa_pointer * pagemap
Definition: dsa.c:356
char * mapped_address
Definition: dsa.c:353

References Assert(), dsa_area::control, CurrentResourceOwner, DSA_AREA_LOCK, DSA_MAX_SEGMENTS, DSA_SEGMENT_HEADER_MAGIC, ereport, errcode(), errmsg(), ERROR, dsa_segment_map::fpm, dsa_area_control::freed_segment_counter, dsa_area::freed_segment_counter, dsa_area_control::handle, dsa_segment_map::header, dsa_area::high_segment_index, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), dsa_segment_header::magic, dsa_segment_map::mapped_address, MAXALIGN, dsa_segment_map::pagemap, palloc(), dsa_area_control::refcnt, dsa_area::resowner, dsa_segment_map::segment, dsa_area_control::segment_handles, dsa_area_control::segment_header, and dsa_area::segment_maps.

Referenced by dsa_attach(), and dsa_attach_in_place().

◆ check_for_freed_segments()

static void check_for_freed_segments ( dsa_area area)
static

Definition at line 2257 of file dsa.c.

2258 {
2259  size_t freed_segment_counter;
2260 
2261  /*
2262  * Any other process that has freed a segment has incremented
2263  * freed_segment_counter while holding an LWLock, and that must precede
2264  * any backend creating a new segment in the same slot while holding an
2265  * LWLock, and that must precede the creation of any dsa_pointer pointing
2266  * into the new segment which might reach us here, and the caller must
2267  * have sent the dsa_pointer to this process using appropriate memory
2268  * synchronization (some kind of locking or atomic primitive or system
2269  * call). So all we need to do on the reading side is ask for the load of
2270  * freed_segment_counter to follow the caller's load of the dsa_pointer it
2271  * has, and we can be sure to detect any segments that had been freed as
2272  * of the time that the dsa_pointer reached this process.
2273  */
2274  pg_read_barrier();
2275  freed_segment_counter = area->control->freed_segment_counter;
2276  if (unlikely(area->freed_segment_counter != freed_segment_counter))
2277  {
2278  /* Check all currently mapped segments to find what's been freed. */
2282  }
2283 }
#define pg_read_barrier()
Definition: atomics.h:151
#define unlikely(x)
Definition: c.h:298
static void check_for_freed_segments_locked(dsa_area *area)
Definition: dsa.c:2293

References check_for_freed_segments_locked(), dsa_area::control, DSA_AREA_LOCK, dsa_area_control::freed_segment_counter, dsa_area::freed_segment_counter, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), pg_read_barrier, and unlikely.

Referenced by dsa_free(), and dsa_get_address().

◆ check_for_freed_segments_locked()

static void check_for_freed_segments_locked ( dsa_area area)
static

Definition at line 2293 of file dsa.c.

2294 {
2295  size_t freed_segment_counter;
2296  int i;
2297 
2299  freed_segment_counter = area->control->freed_segment_counter;
2300  if (unlikely(area->freed_segment_counter != freed_segment_counter))
2301  {
2302  for (i = 0; i <= area->high_segment_index; ++i)
2303  {
2304  if (area->segment_maps[i].header != NULL &&
2305  area->segment_maps[i].header->freed)
2306  {
2307  dsm_detach(area->segment_maps[i].segment);
2308  area->segment_maps[i].segment = NULL;
2309  area->segment_maps[i].header = NULL;
2310  area->segment_maps[i].mapped_address = NULL;
2311  }
2312  }
2313  area->freed_segment_counter = freed_segment_counter;
2314  }
2315 }
void dsm_detach(dsm_segment *seg)
Definition: dsm.c:803
int i
Definition: isn.c:73

References Assert(), dsa_area::control, DSA_AREA_LOCK, dsm_detach(), dsa_segment_header::freed, dsa_area_control::freed_segment_counter, dsa_area::freed_segment_counter, dsa_segment_map::header, dsa_area::high_segment_index, i, LWLockHeldByMe(), dsa_segment_map::mapped_address, dsa_segment_map::segment, dsa_area::segment_maps, and unlikely.

Referenced by check_for_freed_segments(), destroy_superblock(), dsa_dump(), and get_best_segment().

◆ contiguous_pages_to_segment_bin()

static size_t contiguous_pages_to_segment_bin ( size_t  n)
inlinestatic

Definition at line 141 of file dsa.c.

142 {
143  size_t bin;
144 
145  if (n == 0)
146  bin = 0;
147  else
148  bin = pg_leftmost_one_pos_size_t(n) + 1;
149 
150  return Min(bin, DSA_NUM_SEGMENT_BINS - 1);
151 }
#define Min(x, y)
Definition: c.h:991
#define DSA_NUM_SEGMENT_BINS
Definition: dsa.c:133
#define pg_leftmost_one_pos_size_t
Definition: pg_bitutils.h:338

References DSA_NUM_SEGMENT_BINS, Min, and pg_leftmost_one_pos_size_t.

Referenced by create_internal(), get_best_segment(), make_new_segment(), and rebin_segment().

◆ create_internal()

static dsa_area * create_internal ( void *  place,
size_t  size,
int  tranche_id,
dsm_handle  control_handle,
dsm_segment control_segment 
)
static

Definition at line 1231 of file dsa.c.

1235 {
1236  dsa_area_control *control;
1237  dsa_area *area;
1238  dsa_segment_map *segment_map;
1239  size_t usable_pages;
1240  size_t total_pages;
1241  size_t metadata_bytes;
1242  int i;
1243 
1244  /* Sanity check on the space we have to work in. */
1245  if (size < dsa_minimum_size())
1246  elog(ERROR, "dsa_area space must be at least %zu, but %zu provided",
1247  dsa_minimum_size(), size);
1248 
1249  /* Now figure out how much space is usable */
1250  total_pages = size / FPM_PAGE_SIZE;
1251  metadata_bytes =
1252  MAXALIGN(sizeof(dsa_area_control)) +
1253  MAXALIGN(sizeof(FreePageManager)) +
1254  total_pages * sizeof(dsa_pointer);
1255  /* Add padding up to next page boundary. */
1256  if (metadata_bytes % FPM_PAGE_SIZE != 0)
1257  metadata_bytes += FPM_PAGE_SIZE - (metadata_bytes % FPM_PAGE_SIZE);
1258  Assert(metadata_bytes <= size);
1259  usable_pages = (size - metadata_bytes) / FPM_PAGE_SIZE;
1260 
1261  /*
1262  * Initialize the dsa_area_control object located at the start of the
1263  * space.
1264  */
1265  control = (dsa_area_control *) place;
1266  memset(place, 0, sizeof(*control));
1267  control->segment_header.magic =
1268  DSA_SEGMENT_HEADER_MAGIC ^ control_handle ^ 0;
1271  control->segment_header.usable_pages = usable_pages;
1272  control->segment_header.freed = false;
1274  control->handle = control_handle;
1275  control->max_total_segment_size = (size_t) -1;
1276  control->total_segment_size = size;
1277  control->segment_handles[0] = control_handle;
1278  for (i = 0; i < DSA_NUM_SEGMENT_BINS; ++i)
1280  control->refcnt = 1;
1281  control->lwlock_tranche_id = tranche_id;
1282 
1283  /*
1284  * Create the dsa_area object that this backend will use to access the
1285  * area. Other backends will need to obtain their own dsa_area object by
1286  * attaching.
1287  */
1288  area = palloc(sizeof(dsa_area));
1289  area->control = control;
1291  memset(area->segment_maps, 0, sizeof(dsa_segment_map) * DSA_MAX_SEGMENTS);
1292  area->high_segment_index = 0;
1293  area->freed_segment_counter = 0;
1294  LWLockInitialize(&control->lock, control->lwlock_tranche_id);
1295  for (i = 0; i < DSA_NUM_SIZE_CLASSES; ++i)
1297  control->lwlock_tranche_id);
1298 
1299  /* Set up the segment map for this process's mapping. */
1300  segment_map = &area->segment_maps[0];
1301  segment_map->segment = control_segment;
1302  segment_map->mapped_address = place;
1303  segment_map->header = (dsa_segment_header *) place;
1304  segment_map->fpm = (FreePageManager *)
1305  (segment_map->mapped_address +
1306  MAXALIGN(sizeof(dsa_area_control)));
1307  segment_map->pagemap = (dsa_pointer *)
1308  (segment_map->mapped_address +
1309  MAXALIGN(sizeof(dsa_area_control)) +
1310  MAXALIGN(sizeof(FreePageManager)));
1311 
1312  /* Set up the free page map. */
1313  FreePageManagerInitialize(segment_map->fpm, segment_map->mapped_address);
1314  /* There can be 0 usable pages if size is dsa_minimum_size(). */
1315 
1316  if (usable_pages > 0)
1317  FreePageManagerPut(segment_map->fpm, metadata_bytes / FPM_PAGE_SIZE,
1318  usable_pages);
1319 
1320  /* Put this segment into the appropriate bin. */
1321  control->segment_bins[contiguous_pages_to_segment_bin(usable_pages)] = 0;
1322  segment_map->header->bin = contiguous_pages_to_segment_bin(usable_pages);
1323 
1324  return area;
1325 }
#define DSA_SEGMENT_INDEX_NONE
Definition: dsa.c:127
#define DSA_INITIAL_SEGMENT_SIZE
Definition: dsa.c:68
static size_t contiguous_pages_to_segment_bin(size_t n)
Definition: dsa.c:141
size_t dsa_minimum_size(void)
Definition: dsa.c:1209
#define elog(elevel,...)
Definition: elog.h:224
void FreePageManagerPut(FreePageManager *fpm, Size first_page, Size npages)
Definition: freepage.c:379
void FreePageManagerInitialize(FreePageManager *fpm, char *base)
Definition: freepage.c:183
#define FPM_PAGE_SIZE
Definition: freepage.h:30
void LWLockInitialize(LWLock *lock, int tranche_id)
Definition: lwlock.c:707
size_t total_segment_size
Definition: dsa.c:322
int lwlock_tranche_id
Definition: dsa.c:334
size_t max_total_segment_size
Definition: dsa.c:324
dsa_segment_index segment_bins[DSA_NUM_SEGMENT_BINS]
Definition: dsa.c:318
LWLock lock
Definition: dsa.c:336
size_t size
Definition: dsa.c:169
dsa_segment_index next
Definition: dsa.c:181
dsa_segment_index prev
Definition: dsa.c:175
size_t usable_pages
Definition: dsa.c:167
size_t bin
Definition: dsa.c:183

References Assert(), dsa_segment_header::bin, contiguous_pages_to_segment_bin(), dsa_area::control, CurrentResourceOwner, DSA_INITIAL_SEGMENT_SIZE, DSA_MAX_SEGMENTS, dsa_minimum_size(), DSA_NUM_SEGMENT_BINS, DSA_NUM_SIZE_CLASSES, DSA_SCLASS_LOCK, DSA_SEGMENT_HEADER_MAGIC, DSA_SEGMENT_INDEX_NONE, elog, ERROR, dsa_segment_map::fpm, FPM_PAGE_SIZE, dsa_segment_header::freed, dsa_area::freed_segment_counter, FreePageManagerInitialize(), FreePageManagerPut(), dsa_area_control::handle, dsa_segment_map::header, dsa_area::high_segment_index, i, dsa_area_control::lock, dsa_area_control::lwlock_tranche_id, LWLockInitialize(), dsa_segment_header::magic, dsa_segment_map::mapped_address, dsa_area_control::max_total_segment_size, MAXALIGN, dsa_segment_header::next, dsa_segment_map::pagemap, palloc(), dsa_segment_header::prev, dsa_area_control::refcnt, dsa_area::resowner, dsa_segment_map::segment, dsa_area_control::segment_bins, dsa_area_control::segment_handles, dsa_area_control::segment_header, dsa_area::segment_maps, dsa_segment_header::size, size, dsa_area_control::total_segment_size, and dsa_segment_header::usable_pages.

Referenced by dsa_create(), and dsa_create_in_place().

◆ destroy_superblock()

static void destroy_superblock ( dsa_area area,
dsa_pointer  span_pointer 
)
static

Definition at line 1842 of file dsa.c.

1843 {
1844  dsa_area_span *span = dsa_get_address(area, span_pointer);
1845  int size_class = span->size_class;
1846  dsa_segment_map *segment_map;
1847 
1848 
1849  /* Remove it from its fullness class list. */
1850  unlink_span(area, span);
1851 
1852  /*
1853  * Note: Here we acquire the area lock while we already hold a per-pool
1854  * lock. We never hold the area lock and then take a pool lock, or we
1855  * could deadlock.
1856  */
1859  segment_map =
1861  FreePageManagerPut(segment_map->fpm,
1863  span->npages);
1864  /* Check if the segment is now entirely free. */
1865  if (fpm_largest(segment_map->fpm) == segment_map->header->usable_pages)
1866  {
1867  dsa_segment_index index = get_segment_index(area, segment_map);
1868 
1869  /* If it's not the segment with extra control data, free it. */
1870  if (index != 0)
1871  {
1872  /*
1873  * Give it back to the OS, and allow other backends to detect that
1874  * they need to detach.
1875  */
1876  unlink_segment(area, segment_map);
1877  segment_map->header->freed = true;
1879  segment_map->header->size);
1880  area->control->total_segment_size -=
1881  segment_map->header->size;
1883  dsm_detach(segment_map->segment);
1885  ++area->control->freed_segment_counter;
1886  segment_map->segment = NULL;
1887  segment_map->header = NULL;
1888  segment_map->mapped_address = NULL;
1889  }
1890  }
1891 
1892  /* Move segment to appropriate bin if necessary. */
1893  if (segment_map->header != NULL)
1894  rebin_segment(area, segment_map);
1895 
1897 
1898  /*
1899  * Span-of-spans blocks store the span which describes them within the
1900  * block itself, so freeing the storage implicitly frees the descriptor
1901  * also. If this is a block of any other type, we need to separately free
1902  * the span object also. This recursive call to dsa_free will acquire the
1903  * span pool's lock. We can't deadlock because the acquisition order is
1904  * always some other pool and then the span pool.
1905  */
1906  if (size_class != DSA_SCLASS_BLOCK_OF_SPANS)
1907  dsa_free(area, span_pointer);
1908 }
static void unlink_segment(dsa_area *area, dsa_segment_map *segment_map)
Definition: dsa.c:1983
#define DSA_EXTRACT_SEGMENT_NUMBER(dp)
Definition: dsa.c:118
#define get_segment_index(area, segment_map_ptr)
Definition: dsa.c:397
#define DSA_EXTRACT_OFFSET(dp)
Definition: dsa.c:121
size_t dsa_segment_index
Definition: dsa.c:124
static void rebin_segment(dsa_area *area, dsa_segment_map *segment_map)
Definition: dsa.c:2321
static dsa_segment_map * get_segment_by_index(dsa_area *area, dsa_segment_index index)
Definition: dsa.c:1762
#define DSA_SCLASS_BLOCK_OF_SPANS
Definition: dsa.c:261
static void unlink_span(dsa_area *area, dsa_area_span *span)
Definition: dsa.c:1911
void dsa_free(dsa_area *area, dsa_pointer dp)
Definition: dsa.c:839
dsm_handle dsm_segment_handle(dsm_segment *seg)
Definition: dsm.c:1123
void dsm_unpin_segment(dsm_handle handle)
Definition: dsm.c:988
#define DSM_HANDLE_INVALID
Definition: dsm_impl.h:58
#define fpm_largest(fpm)
Definition: freepage.h:88
uint16 size_class
Definition: dsa.c:212
size_t npages
Definition: dsa.c:211
Definition: type.h:95

References Assert(), check_for_freed_segments_locked(), dsa_area::control, DSA_AREA_LOCK, DSA_EXTRACT_OFFSET, DSA_EXTRACT_SEGMENT_NUMBER, dsa_free(), dsa_get_address(), DSA_SCLASS_BLOCK_OF_SPANS, dsm_detach(), DSM_HANDLE_INVALID, dsm_segment_handle(), dsm_unpin_segment(), dsa_segment_map::fpm, fpm_largest, FPM_PAGE_SIZE, dsa_segment_header::freed, dsa_area_control::freed_segment_counter, FreePageManagerPut(), get_segment_by_index(), get_segment_index, dsa_segment_map::header, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), dsa_segment_map::mapped_address, dsa_area_span::npages, rebin_segment(), dsa_segment_map::segment, dsa_area_control::segment_handles, dsa_segment_header::size, dsa_area_span::size_class, dsa_area_span::start, dsa_area_control::total_segment_size, unlink_segment(), unlink_span(), and dsa_segment_header::usable_pages.

Referenced by dsa_free(), and dsa_trim().

◆ dsa_allocate_extended()

dsa_pointer dsa_allocate_extended ( dsa_area area,
size_t  size,
int  flags 
)

Definition at line 684 of file dsa.c.

685 {
686  uint16 size_class;
687  dsa_pointer start_pointer;
688  dsa_segment_map *segment_map;
689  dsa_pointer result;
690 
691  Assert(size > 0);
692 
693  /* Sanity check on huge individual allocation size. */
694  if (((flags & DSA_ALLOC_HUGE) != 0 && !AllocHugeSizeIsValid(size)) ||
695  ((flags & DSA_ALLOC_HUGE) == 0 && !AllocSizeIsValid(size)))
696  elog(ERROR, "invalid DSA memory alloc request size %zu", size);
697 
698  /*
699  * If bigger than the largest size class, just grab a run of pages from
700  * the free page manager, instead of allocating an object from a pool.
701  * There will still be a span, but it's a special class of span that
702  * manages this whole allocation and simply gives all pages back to the
703  * free page manager when dsa_free is called.
704  */
706  {
707  size_t npages = fpm_size_to_pages(size);
708  size_t first_page;
709  dsa_pointer span_pointer;
711 
712  /* Obtain a span object. */
713  span_pointer = alloc_object(area, DSA_SCLASS_BLOCK_OF_SPANS);
714  if (!DsaPointerIsValid(span_pointer))
715  {
716  /* Raise error unless asked not to. */
717  if ((flags & DSA_ALLOC_NO_OOM) == 0)
718  ereport(ERROR,
719  (errcode(ERRCODE_OUT_OF_MEMORY),
720  errmsg("out of memory"),
721  errdetail("Failed on DSA request of size %zu.",
722  size)));
723  return InvalidDsaPointer;
724  }
725 
727 
728  /* Find a segment from which to allocate. */
729  segment_map = get_best_segment(area, npages);
730  if (segment_map == NULL)
731  segment_map = make_new_segment(area, npages);
732  if (segment_map == NULL)
733  {
734  /* Can't make any more segments: game over. */
736  dsa_free(area, span_pointer);
737 
738  /* Raise error unless asked not to. */
739  if ((flags & DSA_ALLOC_NO_OOM) == 0)
740  ereport(ERROR,
741  (errcode(ERRCODE_OUT_OF_MEMORY),
742  errmsg("out of memory"),
743  errdetail("Failed on DSA request of size %zu.",
744  size)));
745  return InvalidDsaPointer;
746  }
747 
748  /*
749  * Ask the free page manager for a run of pages. This should always
750  * succeed, since both get_best_segment and make_new_segment should
751  * only return a non-NULL pointer if it actually contains enough
752  * contiguous freespace. If it does fail, something in our backend
753  * private state is out of whack, so use FATAL to kill the process.
754  */
755  if (!FreePageManagerGet(segment_map->fpm, npages, &first_page))
756  elog(FATAL,
757  "dsa_allocate could not find %zu free pages", npages);
759 
760  start_pointer = DSA_MAKE_POINTER(get_segment_index(area, segment_map),
761  first_page * FPM_PAGE_SIZE);
762 
763  /* Initialize span and pagemap. */
765  LW_EXCLUSIVE);
766  init_span(area, span_pointer, pool, start_pointer, npages,
768  segment_map->pagemap[first_page] = span_pointer;
770 
771  /* Zero-initialize the memory if requested. */
772  if ((flags & DSA_ALLOC_ZERO) != 0)
773  memset(dsa_get_address(area, start_pointer), 0, size);
774 
775  return start_pointer;
776  }
777 
778  /* Map allocation to a size class. */
780  {
781  int mapidx;
782 
783  /* For smaller sizes we have a lookup table... */
784  mapidx = ((size + DSA_SIZE_CLASS_MAP_QUANTUM - 1) /
786  size_class = dsa_size_class_map[mapidx];
787  }
788  else
789  {
790  uint16 min;
791  uint16 max;
792 
793  /* ... and for the rest we search by binary chop. */
795  max = lengthof(dsa_size_classes) - 1;
796 
797  while (min < max)
798  {
799  uint16 mid = (min + max) / 2;
800  uint16 class_size = dsa_size_classes[mid];
801 
802  if (class_size < size)
803  min = mid + 1;
804  else
805  max = mid;
806  }
807 
808  size_class = min;
809  }
810  Assert(size <= dsa_size_classes[size_class]);
811  Assert(size_class == 0 || size > dsa_size_classes[size_class - 1]);
812 
813  /* Attempt to allocate an object from the appropriate pool. */
814  result = alloc_object(area, size_class);
815 
816  /* Check for failure to allocate. */
817  if (!DsaPointerIsValid(result))
818  {
819  /* Raise error unless asked not to. */
820  if ((flags & DSA_ALLOC_NO_OOM) == 0)
821  ereport(ERROR,
822  (errcode(ERRCODE_OUT_OF_MEMORY),
823  errmsg("out of memory"),
824  errdetail("Failed on DSA request of size %zu.", size)));
825  return InvalidDsaPointer;
826  }
827 
828  /* Zero-initialize the memory if requested. */
829  if ((flags & DSA_ALLOC_ZERO) != 0)
830  memset(dsa_get_address(area, result), 0, size);
831 
832  return result;
833 }
unsigned short uint16
Definition: c.h:492
#define lengthof(array)
Definition: c.h:775
#define DSA_MAKE_POINTER(segment_number, offset)
Definition: dsa.c:114
static dsa_pointer alloc_object(dsa_area *area, int size_class)
Definition: dsa.c:1477
#define DSA_SIZE_CLASS_MAP_QUANTUM
Definition: dsa.c:280
static const uint8 dsa_size_class_map[]
Definition: dsa.c:270
static dsa_segment_map * make_new_segment(dsa_area *area, size_t requested_pages)
Definition: dsa.c:2086
#define DSA_SCLASS_SPAN_LARGE
Definition: dsa.c:262
static void init_span(dsa_area *area, dsa_pointer span_pointer, dsa_area_pool *pool, dsa_pointer start, size_t npages, uint16 size_class)
Definition: dsa.c:1382
static dsa_segment_map * get_best_segment(dsa_area *area, size_t npages)
Definition: dsa.c:2015
#define DSA_ALLOC_NO_OOM
Definition: dsa.h:74
#define DSA_ALLOC_HUGE
Definition: dsa.h:73
#define DSA_ALLOC_ZERO
Definition: dsa.h:75
int errdetail(const char *fmt,...)
Definition: elog.c:1205
#define FATAL
Definition: elog.h:41
bool FreePageManagerGet(FreePageManager *fpm, Size npages, Size *first_page)
Definition: freepage.c:210
#define fpm_size_to_pages(sz)
Definition: freepage.h:74
#define AllocHugeSizeIsValid(size)
Definition: memutils.h:49
#define AllocSizeIsValid(size)
Definition: memutils.h:42

References alloc_object(), AllocHugeSizeIsValid, AllocSizeIsValid, Assert(), dsa_area::control, DSA_ALLOC_HUGE, DSA_ALLOC_NO_OOM, DSA_ALLOC_ZERO, DSA_AREA_LOCK, dsa_free(), dsa_get_address(), DSA_MAKE_POINTER, DSA_SCLASS_BLOCK_OF_SPANS, DSA_SCLASS_LOCK, DSA_SCLASS_SPAN_LARGE, dsa_size_class_map, DSA_SIZE_CLASS_MAP_QUANTUM, dsa_size_classes, DsaPointerIsValid, elog, ereport, errcode(), errdetail(), errmsg(), ERROR, FATAL, dsa_segment_map::fpm, FPM_PAGE_SIZE, fpm_size_to_pages, FreePageManagerGet(), get_best_segment(), get_segment_index, init_span(), InvalidDsaPointer, lengthof, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), make_new_segment(), dsa_segment_map::pagemap, dsa_area_control::pools, and size.

Referenced by dshash_create(), and pagetable_allocate().

◆ dsa_attach()

dsa_area* dsa_attach ( dsa_handle  handle)

Definition at line 523 of file dsa.c.

524 {
525  dsm_segment *segment;
526  dsa_area *area;
527 
528  /*
529  * An area handle is really a DSM segment handle for the first segment, so
530  * we go ahead and attach to that.
531  */
532  segment = dsm_attach(handle);
533  if (segment == NULL)
534  ereport(ERROR,
535  (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
536  errmsg("could not attach to dynamic shared area")));
537 
538  area = attach_internal(dsm_segment_address(segment), segment, handle);
539 
540  /* Clean up when the control segment detaches. */
543 
544  return area;
545 }
void dsa_on_dsm_detach_release_in_place(dsm_segment *segment, Datum place)
Definition: dsa.c:589
static dsa_area * attach_internal(void *place, dsm_segment *segment, dsa_handle handle)
Definition: dsa.c:1331
void * dsm_segment_address(dsm_segment *seg)
Definition: dsm.c:1095
void on_dsm_detach(dsm_segment *seg, on_dsm_detach_callback function, Datum arg)
Definition: dsm.c:1132
dsm_segment * dsm_attach(dsm_handle h)
Definition: dsm.c:665
static Datum PointerGetDatum(const void *X)
Definition: postgres.h:322

References attach_internal(), dsa_on_dsm_detach_release_in_place(), dsm_attach(), dsm_segment_address(), ereport, errcode(), errmsg(), ERROR, on_dsm_detach(), and PointerGetDatum().

Referenced by init_dsm_registry(), and logicalrep_launcher_attach_dshmem().

◆ dsa_attach_in_place()

dsa_area* dsa_attach_in_place ( void *  place,
dsm_segment segment 
)

Definition at line 558 of file dsa.c.

559 {
560  dsa_area *area;
561 
562  area = attach_internal(place, NULL, DSA_HANDLE_INVALID);
563 
564  /*
565  * Clean up when the control segment detaches, if a containing DSM segment
566  * was provided.
567  */
568  if (segment != NULL)
570  PointerGetDatum(place));
571 
572  return area;
573 }
#define DSA_HANDLE_INVALID
Definition: dsa.h:103

References attach_internal(), DSA_HANDLE_INVALID, dsa_on_dsm_detach_release_in_place(), on_dsm_detach(), and PointerGetDatum().

Referenced by AttachSession(), ParallelQueryMain(), and pgstat_attach_shmem().

◆ dsa_create()

dsa_area* dsa_create ( int  tranche_id)

Definition at line 437 of file dsa.c.

438 {
439  dsm_segment *segment;
440  dsa_area *area;
441 
442  /*
443  * Create the DSM segment that will hold the shared control object and the
444  * first segment of usable space.
445  */
446  segment = dsm_create(DSA_INITIAL_SEGMENT_SIZE, 0);
447 
448  /*
449  * All segments backing this area are pinned, so that DSA can explicitly
450  * control their lifetime (otherwise a newly created segment belonging to
451  * this area might be freed when the only backend that happens to have it
452  * mapped in ends, corrupting the area).
453  */
454  dsm_pin_segment(segment);
455 
456  /* Create a new DSA area with the control object in this segment. */
457  area = create_internal(dsm_segment_address(segment),
459  tranche_id,
460  dsm_segment_handle(segment), segment);
461 
462  /* Clean up when the control segment detaches. */
465 
466  return area;
467 }
static dsa_area * create_internal(void *place, size_t size, int tranche_id, dsm_handle control_handle, dsm_segment *control_segment)
Definition: dsa.c:1231
dsm_segment * dsm_create(Size size, int flags)
Definition: dsm.c:516
void dsm_pin_segment(dsm_segment *seg)
Definition: dsm.c:955

References create_internal(), DSA_INITIAL_SEGMENT_SIZE, dsa_on_dsm_detach_release_in_place(), dsm_create(), dsm_pin_segment(), dsm_segment_address(), dsm_segment_handle(), on_dsm_detach(), and PointerGetDatum().

Referenced by init_dsm_registry(), logicalrep_launcher_attach_dshmem(), test_basic(), test_dsa_basic(), test_dsa_resowners(), test_empty(), and test_random().

◆ dsa_create_in_place()

dsa_area* dsa_create_in_place ( void *  place,
size_t  size,
int  tranche_id,
dsm_segment segment 
)

Definition at line 486 of file dsa.c.

488 {
489  dsa_area *area;
490 
491  area = create_internal(place, size, tranche_id,
492  DSM_HANDLE_INVALID, NULL);
493 
494  /*
495  * Clean up when the control segment detaches, if a containing DSM segment
496  * was provided.
497  */
498  if (segment != NULL)
500  PointerGetDatum(place));
501 
502  return area;
503 }

References create_internal(), dsa_on_dsm_detach_release_in_place(), DSM_HANDLE_INVALID, on_dsm_detach(), PointerGetDatum(), and size.

Referenced by ExecInitParallelPlan(), GetSessionDsmHandle(), and StatsShmemInit().

◆ dsa_detach()

void dsa_detach ( dsa_area area)

Definition at line 1957 of file dsa.c.

1958 {
1959  int i;
1960 
1961  /* Detach from all segments. */
1962  for (i = 0; i <= area->high_segment_index; ++i)
1963  if (area->segment_maps[i].segment != NULL)
1964  dsm_detach(area->segment_maps[i].segment);
1965 
1966  /*
1967  * Note that 'detaching' (= detaching from DSM segments) doesn't include
1968  * 'releasing' (= adjusting the reference count). It would be nice to
1969  * combine these operations, but client code might never get around to
1970  * calling dsa_detach because of an error path, and a detach hook on any
1971  * particular segment is too late to detach other segments in the area
1972  * without risking a 'leak' warning in the non-error path.
1973  */
1974 
1975  /* Free the backend-local area object. */
1976  pfree(area);
1977 }
void pfree(void *pointer)
Definition: mcxt.c:1508

References dsm_detach(), dsa_area::high_segment_index, i, pfree(), dsa_segment_map::segment, and dsa_area::segment_maps.

Referenced by DetachSession(), ExecParallelCleanup(), ParallelQueryMain(), pgstat_detach_shmem(), StatsShmemInit(), test_basic(), test_dsa_basic(), test_dsa_resowners(), test_empty(), and test_random().

◆ dsa_dump()

void dsa_dump ( dsa_area area)

Definition at line 1101 of file dsa.c.

1102 {
1103  size_t i,
1104  j;
1105 
1106  /*
1107  * Note: This gives an inconsistent snapshot as it acquires and releases
1108  * individual locks as it goes...
1109  */
1110 
1113  fprintf(stderr, "dsa_area handle %x:\n", area->control->handle);
1114  fprintf(stderr, " max_total_segment_size: %zu\n",
1116  fprintf(stderr, " total_segment_size: %zu\n",
1117  area->control->total_segment_size);
1118  fprintf(stderr, " refcnt: %d\n", area->control->refcnt);
1119  fprintf(stderr, " pinned: %c\n", area->control->pinned ? 't' : 'f');
1120  fprintf(stderr, " segment bins:\n");
1121  for (i = 0; i < DSA_NUM_SEGMENT_BINS; ++i)
1122  {
1124  {
1125  dsa_segment_index segment_index;
1126 
1127  if (i == 0)
1128  fprintf(stderr,
1129  " segment bin %zu (no contiguous free pages):\n", i);
1130  else
1131  fprintf(stderr,
1132  " segment bin %zu (at least %d contiguous pages free):\n",
1133  i, 1 << (i - 1));
1134  segment_index = area->control->segment_bins[i];
1135  while (segment_index != DSA_SEGMENT_INDEX_NONE)
1136  {
1137  dsa_segment_map *segment_map;
1138 
1139  segment_map =
1140  get_segment_by_index(area, segment_index);
1141 
1142  fprintf(stderr,
1143  " segment index %zu, usable_pages = %zu, "
1144  "contiguous_pages = %zu, mapped at %p\n",
1145  segment_index,
1146  segment_map->header->usable_pages,
1147  fpm_largest(segment_map->fpm),
1148  segment_map->mapped_address);
1149  segment_index = segment_map->header->next;
1150  }
1151  }
1152  }
1154 
1155  fprintf(stderr, " pools:\n");
1156  for (i = 0; i < DSA_NUM_SIZE_CLASSES; ++i)
1157  {
1158  bool found = false;
1159 
1161  for (j = 0; j < DSA_FULLNESS_CLASSES; ++j)
1162  if (DsaPointerIsValid(area->control->pools[i].spans[j]))
1163  found = true;
1164  if (found)
1165  {
1167  fprintf(stderr, " pool for blocks of span objects:\n");
1168  else if (i == DSA_SCLASS_SPAN_LARGE)
1169  fprintf(stderr, " pool for large object spans:\n");
1170  else
1171  fprintf(stderr,
1172  " pool for size class %zu (object size %hu bytes):\n",
1173  i, dsa_size_classes[i]);
1174  for (j = 0; j < DSA_FULLNESS_CLASSES; ++j)
1175  {
1176  if (!DsaPointerIsValid(area->control->pools[i].spans[j]))
1177  fprintf(stderr, " fullness class %zu is empty\n", j);
1178  else
1179  {
1180  dsa_pointer span_pointer = area->control->pools[i].spans[j];
1181 
1182  fprintf(stderr, " fullness class %zu:\n", j);
1183  while (DsaPointerIsValid(span_pointer))
1184  {
1185  dsa_area_span *span;
1186 
1187  span = dsa_get_address(area, span_pointer);
1188  fprintf(stderr,
1189  " span descriptor at "
1190  DSA_POINTER_FORMAT ", superblock at "
1192  ", pages = %zu, objects free = %hu/%hu\n",
1193  span_pointer, span->start, span->npages,
1194  span->nallocatable, span->nmax);
1195  span_pointer = span->nextspan;
1196  }
1197  }
1198  }
1199  }
1201  }
1202 }
#define DSA_POINTER_FORMAT
Definition: dsa.h:69
int j
Definition: isn.c:74
#define fprintf
Definition: port.h:242
bool pinned
Definition: dsa.c:330
uint16 nmax
Definition: dsa.c:216

References check_for_freed_segments_locked(), dsa_area::control, DSA_AREA_LOCK, DSA_FULLNESS_CLASSES, dsa_get_address(), DSA_NUM_SEGMENT_BINS, DSA_NUM_SIZE_CLASSES, DSA_POINTER_FORMAT, DSA_SCLASS_BLOCK_OF_SPANS, DSA_SCLASS_LOCK, DSA_SCLASS_SPAN_LARGE, DSA_SEGMENT_INDEX_NONE, dsa_size_classes, DsaPointerIsValid, dsa_segment_map::fpm, fpm_largest, fprintf, get_segment_by_index(), dsa_area_control::handle, dsa_segment_map::header, i, j, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), dsa_segment_map::mapped_address, dsa_area_control::max_total_segment_size, dsa_area_span::nallocatable, dsa_segment_header::next, dsa_area_span::nextspan, dsa_area_span::nmax, dsa_area_span::npages, dsa_area_control::pinned, dsa_area_control::pools, dsa_area_control::refcnt, dsa_area_control::segment_bins, dsa_area_pool::spans, dsa_area_span::start, dsa_area_control::total_segment_size, and dsa_segment_header::usable_pages.

◆ dsa_free()

void dsa_free ( dsa_area area,
dsa_pointer  dp 
)

Definition at line 839 of file dsa.c.

840 {
841  dsa_segment_map *segment_map;
842  int pageno;
843  dsa_pointer span_pointer;
844  dsa_area_span *span;
845  char *superblock;
846  char *object;
847  size_t size;
848  int size_class;
849 
850  /* Make sure we don't have a stale segment in the slot 'dp' refers to. */
852 
853  /* Locate the object, span and pool. */
854  segment_map = get_segment_by_index(area, DSA_EXTRACT_SEGMENT_NUMBER(dp));
855  pageno = DSA_EXTRACT_OFFSET(dp) / FPM_PAGE_SIZE;
856  span_pointer = segment_map->pagemap[pageno];
857  span = dsa_get_address(area, span_pointer);
858  superblock = dsa_get_address(area, span->start);
859  object = dsa_get_address(area, dp);
860  size_class = span->size_class;
861  size = dsa_size_classes[size_class];
862 
863  /*
864  * Special case for large objects that live in a special span: we return
865  * those pages directly to the free page manager and free the span.
866  */
867  if (span->size_class == DSA_SCLASS_SPAN_LARGE)
868  {
869 
870 #ifdef CLOBBER_FREED_MEMORY
871  memset(object, 0x7f, span->npages * FPM_PAGE_SIZE);
872 #endif
873 
874  /* Give pages back to free page manager. */
876  FreePageManagerPut(segment_map->fpm,
878  span->npages);
879 
880  /* Move segment to appropriate bin if necessary. */
881  rebin_segment(area, segment_map);
883 
884  /* Unlink span. */
886  LW_EXCLUSIVE);
887  unlink_span(area, span);
889  /* Free the span object so it can be reused. */
890  dsa_free(area, span_pointer);
891  return;
892  }
893 
894 #ifdef CLOBBER_FREED_MEMORY
895  memset(object, 0x7f, size);
896 #endif
897 
898  LWLockAcquire(DSA_SCLASS_LOCK(area, size_class), LW_EXCLUSIVE);
899 
900  /* Put the object on the span's freelist. */
901  Assert(object >= superblock);
902  Assert(object < superblock + DSA_SUPERBLOCK_SIZE);
903  Assert((object - superblock) % size == 0);
904  NextFreeObjectIndex(object) = span->firstfree;
905  span->firstfree = (object - superblock) / size;
906  ++span->nallocatable;
907 
908  /*
909  * See if the span needs to moved to a different fullness class, or be
910  * freed so its pages can be given back to the segment.
911  */
912  if (span->nallocatable == 1 && span->fclass == DSA_FULLNESS_CLASSES - 1)
913  {
914  /*
915  * The block was completely full and is located in the
916  * highest-numbered fullness class, which is never scanned for free
917  * chunks. We must move it to the next-lower fullness class.
918  */
919  unlink_span(area, span);
920  add_span_to_fullness_class(area, span, span_pointer,
922 
923  /*
924  * If this is the only span, and there is no active span, then we
925  * should probably move this span to fullness class 1. (Otherwise if
926  * you allocate exactly all the objects in the only span, it moves to
927  * class 3, then you free them all, it moves to 2, and then is given
928  * back, leaving no active span).
929  */
930  }
931  else if (span->nallocatable == span->nmax &&
932  (span->fclass != 1 || span->prevspan != InvalidDsaPointer))
933  {
934  /*
935  * This entire block is free, and it's not the active block for this
936  * size class. Return the memory to the free page manager. We don't
937  * do this for the active block to prevent hysteresis: if we
938  * repeatedly allocate and free the only chunk in the active block, it
939  * will be very inefficient if we deallocate and reallocate the block
940  * every time.
941  */
942  destroy_superblock(area, span_pointer);
943  }
944 
945  LWLockRelease(DSA_SCLASS_LOCK(area, size_class));
946 }
static void check_for_freed_segments(dsa_area *area)
Definition: dsa.c:2257
static void add_span_to_fullness_class(dsa_area *area, dsa_area_span *span, dsa_pointer span_pointer, int fclass)
Definition: dsa.c:1934
#define DSA_SUPERBLOCK_SIZE
Definition: dsa.c:394
static void destroy_superblock(dsa_area *area, dsa_pointer span_pointer)
Definition: dsa.c:1842

References add_span_to_fullness_class(), Assert(), check_for_freed_segments(), destroy_superblock(), DSA_AREA_LOCK, DSA_EXTRACT_OFFSET, DSA_EXTRACT_SEGMENT_NUMBER, DSA_FULLNESS_CLASSES, dsa_get_address(), DSA_SCLASS_LOCK, DSA_SCLASS_SPAN_LARGE, dsa_size_classes, DSA_SUPERBLOCK_SIZE, dsa_area_span::fclass, dsa_area_span::firstfree, dsa_segment_map::fpm, FPM_PAGE_SIZE, FreePageManagerPut(), get_segment_by_index(), InvalidDsaPointer, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), dsa_area_span::nallocatable, NextFreeObjectIndex, dsa_area_span::nmax, dsa_area_span::npages, dsa_segment_map::pagemap, dsa_area_span::prevspan, rebin_segment(), size, dsa_area_span::size_class, dsa_area_span::start, and unlink_span().

Referenced by delete_item_from_bucket(), delete_key_from_bucket(), destroy_superblock(), dsa_allocate_extended(), dshash_create(), dshash_destroy(), ExecHashTableDetach(), ExecHashTableDetachBatch(), ExecParallelCleanup(), ExecParallelHashIncreaseNumBatches(), ExecParallelHashIncreaseNumBuckets(), ExecParallelHashRepartitionFirst(), ExecParallelReinitialize(), find_or_make_matching_shared_tupledesc(), pagetable_free(), pgstat_free_entry(), resize(), tbm_free_shared_area(), test_dsa_basic(), and test_dsa_resowners().

◆ dsa_get_address()

void* dsa_get_address ( dsa_area area,
dsa_pointer  dp 
)

Definition at line 955 of file dsa.c.

956 {
958  size_t offset;
959 
960  /* Convert InvalidDsaPointer to NULL. */
961  if (!DsaPointerIsValid(dp))
962  return NULL;
963 
964  /* Process any requests to detach from freed segments. */
966 
967  /* Break the dsa_pointer into its components. */
969  offset = DSA_EXTRACT_OFFSET(dp);
971 
972  /* Check if we need to cause this segment to be mapped in. */
973  if (unlikely(area->segment_maps[index].mapped_address == NULL))
974  {
975  /* Call for effect (we don't need the result). */
977  }
978 
979  return area->segment_maps[index].mapped_address + offset;
980 }

References Assert(), check_for_freed_segments(), DSA_EXTRACT_OFFSET, DSA_EXTRACT_SEGMENT_NUMBER, DSA_MAX_SEGMENTS, DsaPointerIsValid, get_segment_by_index(), dsa_segment_map::mapped_address, dsa_area::segment_maps, and unlikely.

Referenced by add_span_to_fullness_class(), alloc_object(), delete_item_from_bucket(), delete_key_from_bucket(), destroy_superblock(), dsa_allocate_extended(), dsa_dump(), dsa_free(), dsa_trim(), dshash_attach(), dshash_create(), dshash_destroy(), dshash_dump(), dshash_seq_next(), ensure_active_superblock(), ensure_valid_bucket_pointers(), ExecHashTableDetachBatch(), ExecParallelHashEnsureBatchAccessors(), ExecParallelHashFirstTuple(), ExecParallelHashIncreaseNumBatches(), ExecParallelHashIncreaseNumBuckets(), ExecParallelHashJoinSetUpBatches(), ExecParallelHashNextTuple(), ExecParallelHashPopChunkQueue(), ExecParallelHashRepartitionRest(), ExecParallelHashTableAlloc(), ExecParallelHashTableSetCurrentBatch(), ExecParallelHashTupleAlloc(), find_in_bucket(), find_or_make_matching_shared_tupledesc(), init_span(), insert_into_bucket(), insert_item_into_bucket(), lookup_rowtype_tupdesc_internal(), pagetable_allocate(), ParallelQueryMain(), pgstat_build_snapshot(), pgstat_get_entry_ref(), pgstat_init_entry(), pgstat_reinit_entry(), pgstat_reset_matching_entries(), pgstat_write_statsfile(), resize(), SerializeParamExecParams(), share_tupledesc(), shared_record_table_compare(), shared_record_table_hash(), tbm_attach_shared_iterate(), tbm_free_shared_area(), tbm_prepare_shared_iterate(), test_dsa_basic(), test_dsa_resowners(), transfer_first_span(), and unlink_span().

◆ dsa_get_handle()

dsa_handle dsa_get_handle ( dsa_area area)

Definition at line 511 of file dsa.c.

512 {
514  return area->control->handle;
515 }

References Assert(), dsa_area::control, DSA_HANDLE_INVALID, and dsa_area_control::handle.

Referenced by init_dsm_registry(), and logicalrep_launcher_attach_dshmem().

◆ dsa_get_total_size()

size_t dsa_get_total_size ( dsa_area area)

Definition at line 1040 of file dsa.c.

1041 {
1042  size_t size;
1043 
1045  size = area->control->total_segment_size;
1047 
1048  return size;
1049 }

References dsa_area::control, DSA_AREA_LOCK, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), size, and dsa_area_control::total_segment_size.

◆ dsa_minimum_size()

size_t dsa_minimum_size ( void  )

Definition at line 1209 of file dsa.c.

1210 {
1211  size_t size;
1212  int pages = 0;
1213 
1214  size = MAXALIGN(sizeof(dsa_area_control)) +
1215  MAXALIGN(sizeof(FreePageManager));
1216 
1217  /* Figure out how many pages we need, including the page map... */
1218  while (((size + FPM_PAGE_SIZE - 1) / FPM_PAGE_SIZE) > pages)
1219  {
1220  ++pages;
1221  size += sizeof(dsa_pointer);
1222  }
1223 
1224  return pages * FPM_PAGE_SIZE;
1225 }

References FPM_PAGE_SIZE, MAXALIGN, and size.

Referenced by create_internal(), ExecInitParallelPlan(), and pgstat_dsa_init_size().

◆ dsa_on_dsm_detach_release_in_place()

void dsa_on_dsm_detach_release_in_place ( dsm_segment segment,
Datum  place 
)

Definition at line 589 of file dsa.c.

590 {
592 }
void dsa_release_in_place(void *place)
Definition: dsa.c:618
static Pointer DatumGetPointer(Datum X)
Definition: postgres.h:312

References DatumGetPointer(), and dsa_release_in_place().

Referenced by dsa_attach(), dsa_attach_in_place(), dsa_create(), and dsa_create_in_place().

◆ dsa_on_shmem_exit_release_in_place()

void dsa_on_shmem_exit_release_in_place ( int  code,
Datum  place 
)

Definition at line 603 of file dsa.c.

604 {
606 }

References DatumGetPointer(), and dsa_release_in_place().

◆ dsa_pin()

void dsa_pin ( dsa_area area)

Definition at line 988 of file dsa.c.

989 {
991  if (area->control->pinned)
992  {
994  elog(ERROR, "dsa_area already pinned");
995  }
996  area->control->pinned = true;
997  ++area->control->refcnt;
999 }

References dsa_area::control, DSA_AREA_LOCK, elog, ERROR, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), dsa_area_control::pinned, and dsa_area_control::refcnt.

Referenced by init_dsm_registry(), logicalrep_launcher_attach_dshmem(), and StatsShmemInit().

◆ dsa_pin_mapping()

void dsa_pin_mapping ( dsa_area area)

Definition at line 648 of file dsa.c.

649 {
650  int i;
651 
652  if (area->resowner != NULL)
653  {
654  area->resowner = NULL;
655 
656  for (i = 0; i <= area->high_segment_index; ++i)
657  if (area->segment_maps[i].segment != NULL)
659  }
660 }
void dsm_pin_mapping(dsm_segment *seg)
Definition: dsm.c:915

References dsm_pin_mapping(), dsa_area::high_segment_index, i, dsa_area::resowner, dsa_segment_map::segment, and dsa_area::segment_maps.

Referenced by AttachSession(), GetSessionDsmHandle(), init_dsm_registry(), logicalrep_launcher_attach_dshmem(), and pgstat_attach_shmem().

◆ dsa_release_in_place()

void dsa_release_in_place ( void *  place)

Definition at line 618 of file dsa.c.

619 {
620  dsa_area_control *control = (dsa_area_control *) place;
621  int i;
622 
623  LWLockAcquire(&control->lock, LW_EXCLUSIVE);
624  Assert(control->segment_header.magic ==
625  (DSA_SEGMENT_HEADER_MAGIC ^ control->handle ^ 0));
626  Assert(control->refcnt > 0);
627  if (--control->refcnt == 0)
628  {
629  for (i = 0; i <= control->high_segment_index; ++i)
630  {
631  dsm_handle handle;
632 
633  handle = control->segment_handles[i];
634  if (handle != DSM_HANDLE_INVALID)
635  dsm_unpin_segment(handle);
636  }
637  }
638  LWLockRelease(&control->lock);
639 }
uint32 dsm_handle
Definition: dsm_impl.h:55
dsa_segment_index high_segment_index
Definition: dsa.c:326

References Assert(), DSA_SEGMENT_HEADER_MAGIC, DSM_HANDLE_INVALID, dsm_unpin_segment(), dsa_area_control::handle, dsa_area_control::high_segment_index, i, dsa_area_control::lock, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), dsa_segment_header::magic, dsa_area_control::refcnt, dsa_area_control::segment_handles, and dsa_area_control::segment_header.

Referenced by dsa_on_dsm_detach_release_in_place(), and dsa_on_shmem_exit_release_in_place().

◆ dsa_set_size_limit()

void dsa_set_size_limit ( dsa_area area,
size_t  limit 
)

◆ dsa_trim()

void dsa_trim ( dsa_area area)

Definition at line 1056 of file dsa.c.

1057 {
1058  int size_class;
1059 
1060  /*
1061  * Trim in reverse pool order so we get to the spans-of-spans last, just
1062  * in case any become entirely free while processing all the other pools.
1063  */
1064  for (size_class = DSA_NUM_SIZE_CLASSES - 1; size_class >= 0; --size_class)
1065  {
1066  dsa_area_pool *pool = &area->control->pools[size_class];
1067  dsa_pointer span_pointer;
1068 
1069  if (size_class == DSA_SCLASS_SPAN_LARGE)
1070  {
1071  /* Large object frees give back segments aggressively already. */
1072  continue;
1073  }
1074 
1075  /*
1076  * Search fullness class 1 only. That is where we expect to find an
1077  * entirely empty superblock (entirely empty superblocks in other
1078  * fullness classes are returned to the free page map by dsa_free).
1079  */
1080  LWLockAcquire(DSA_SCLASS_LOCK(area, size_class), LW_EXCLUSIVE);
1081  span_pointer = pool->spans[1];
1082  while (DsaPointerIsValid(span_pointer))
1083  {
1084  dsa_area_span *span = dsa_get_address(area, span_pointer);
1085  dsa_pointer next = span->nextspan;
1086 
1087  if (span->nallocatable == span->nmax)
1088  destroy_superblock(area, span_pointer);
1089 
1090  span_pointer = next;
1091  }
1092  LWLockRelease(DSA_SCLASS_LOCK(area, size_class));
1093  }
1094 }
static int32 next
Definition: blutils.c:221

References dsa_area::control, destroy_superblock(), dsa_get_address(), DSA_NUM_SIZE_CLASSES, DSA_SCLASS_LOCK, DSA_SCLASS_SPAN_LARGE, DsaPointerIsValid, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), dsa_area_span::nallocatable, next, dsa_area_span::nextspan, dsa_area_span::nmax, dsa_area_control::pools, and dsa_area_pool::spans.

◆ dsa_unpin()

void dsa_unpin ( dsa_area area)

Definition at line 1007 of file dsa.c.

1008 {
1010  Assert(area->control->refcnt > 1);
1011  if (!area->control->pinned)
1012  {
1014  elog(ERROR, "dsa_area not pinned");
1015  }
1016  area->control->pinned = false;
1017  --area->control->refcnt;
1019 }

References Assert(), dsa_area::control, DSA_AREA_LOCK, elog, ERROR, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), dsa_area_control::pinned, and dsa_area_control::refcnt.

◆ ensure_active_superblock()

static bool ensure_active_superblock ( dsa_area area,
dsa_area_pool pool,
int  size_class 
)
static

Definition at line 1565 of file dsa.c.

1567 {
1568  dsa_pointer span_pointer;
1569  dsa_pointer start_pointer;
1570  size_t obsize = dsa_size_classes[size_class];
1571  size_t nmax;
1572  int fclass;
1573  size_t npages = 1;
1574  size_t first_page;
1575  size_t i;
1576  dsa_segment_map *segment_map;
1577 
1578  Assert(LWLockHeldByMe(DSA_SCLASS_LOCK(area, size_class)));
1579 
1580  /*
1581  * Compute the number of objects that will fit in a block of this size
1582  * class. Span-of-spans blocks are just a single page, and the first
1583  * object isn't available for use because it describes the block-of-spans
1584  * itself.
1585  */
1586  if (size_class == DSA_SCLASS_BLOCK_OF_SPANS)
1587  nmax = FPM_PAGE_SIZE / obsize - 1;
1588  else
1589  nmax = DSA_SUPERBLOCK_SIZE / obsize;
1590 
1591  /*
1592  * If fullness class 1 is empty, try to find a span to put in it by
1593  * scanning higher-numbered fullness classes (excluding the last one,
1594  * whose blocks are certain to all be completely full).
1595  */
1596  for (fclass = 2; fclass < DSA_FULLNESS_CLASSES - 1; ++fclass)
1597  {
1598  span_pointer = pool->spans[fclass];
1599 
1600  while (DsaPointerIsValid(span_pointer))
1601  {
1602  int tfclass;
1603  dsa_area_span *span;
1604  dsa_area_span *nextspan;
1605  dsa_area_span *prevspan;
1606  dsa_pointer next_span_pointer;
1607 
1608  span = (dsa_area_span *)
1609  dsa_get_address(area, span_pointer);
1610  next_span_pointer = span->nextspan;
1611 
1612  /* Figure out what fullness class should contain this span. */
1613  tfclass = (nmax - span->nallocatable)
1614  * (DSA_FULLNESS_CLASSES - 1) / nmax;
1615 
1616  /* Look up next span. */
1617  if (DsaPointerIsValid(span->nextspan))
1618  nextspan = (dsa_area_span *)
1619  dsa_get_address(area, span->nextspan);
1620  else
1621  nextspan = NULL;
1622 
1623  /*
1624  * If utilization has dropped enough that this now belongs in some
1625  * other fullness class, move it there.
1626  */
1627  if (tfclass < fclass)
1628  {
1629  /* Remove from the current fullness class list. */
1630  if (pool->spans[fclass] == span_pointer)
1631  {
1632  /* It was the head; remove it. */
1634  pool->spans[fclass] = span->nextspan;
1635  if (nextspan != NULL)
1636  nextspan->prevspan = InvalidDsaPointer;
1637  }
1638  else
1639  {
1640  /* It was not the head. */
1642  prevspan = (dsa_area_span *)
1643  dsa_get_address(area, span->prevspan);
1644  prevspan->nextspan = span->nextspan;
1645  }
1646  if (nextspan != NULL)
1647  nextspan->prevspan = span->prevspan;
1648 
1649  /* Push onto the head of the new fullness class list. */
1650  span->nextspan = pool->spans[tfclass];
1651  pool->spans[tfclass] = span_pointer;
1652  span->prevspan = InvalidDsaPointer;
1653  if (DsaPointerIsValid(span->nextspan))
1654  {
1655  nextspan = (dsa_area_span *)
1656  dsa_get_address(area, span->nextspan);
1657  nextspan->prevspan = span_pointer;
1658  }
1659  span->fclass = tfclass;
1660  }
1661 
1662  /* Advance to next span on list. */
1663  span_pointer = next_span_pointer;
1664  }
1665 
1666  /* Stop now if we found a suitable block. */
1667  if (DsaPointerIsValid(pool->spans[1]))
1668  return true;
1669  }
1670 
1671  /*
1672  * If there are no blocks that properly belong in fullness class 1, pick
1673  * one from some other fullness class and move it there anyway, so that we
1674  * have an allocation target. Our last choice is to transfer a block
1675  * that's almost empty (and might become completely empty soon if left
1676  * alone), but even that is better than failing, which is what we must do
1677  * if there are no blocks at all with freespace.
1678  */
1679  Assert(!DsaPointerIsValid(pool->spans[1]));
1680  for (fclass = 2; fclass < DSA_FULLNESS_CLASSES - 1; ++fclass)
1681  if (transfer_first_span(area, pool, fclass, 1))
1682  return true;
1683  if (!DsaPointerIsValid(pool->spans[1]) &&
1684  transfer_first_span(area, pool, 0, 1))
1685  return true;
1686 
1687  /*
1688  * We failed to find an existing span with free objects, so we need to
1689  * allocate a new superblock and construct a new span to manage it.
1690  *
1691  * First, get a dsa_area_span object to describe the new superblock block
1692  * ... unless this allocation is for a dsa_area_span object, in which case
1693  * that's surely not going to work. We handle that case by storing the
1694  * span describing a block-of-spans inline.
1695  */
1696  if (size_class != DSA_SCLASS_BLOCK_OF_SPANS)
1697  {
1698  span_pointer = alloc_object(area, DSA_SCLASS_BLOCK_OF_SPANS);
1699  if (!DsaPointerIsValid(span_pointer))
1700  return false;
1701  npages = DSA_PAGES_PER_SUPERBLOCK;
1702  }
1703 
1704  /* Find or create a segment and allocate the superblock. */
1706  segment_map = get_best_segment(area, npages);
1707  if (segment_map == NULL)
1708  {
1709  segment_map = make_new_segment(area, npages);
1710  if (segment_map == NULL)
1711  {
1713  return false;
1714  }
1715  }
1716 
1717  /*
1718  * This shouldn't happen: get_best_segment() or make_new_segment()
1719  * promised that we can successfully allocate npages.
1720  */
1721  if (!FreePageManagerGet(segment_map->fpm, npages, &first_page))
1722  elog(FATAL,
1723  "dsa_allocate could not find %zu free pages for superblock",
1724  npages);
1726 
1727  /* Compute the start of the superblock. */
1728  start_pointer =
1729  DSA_MAKE_POINTER(get_segment_index(area, segment_map),
1730  first_page * FPM_PAGE_SIZE);
1731 
1732  /*
1733  * If this is a block-of-spans, carve the descriptor right out of the
1734  * allocated space.
1735  */
1736  if (size_class == DSA_SCLASS_BLOCK_OF_SPANS)
1737  {
1738  /*
1739  * We have a pointer into the segment. We need to build a dsa_pointer
1740  * from the segment index and offset into the segment.
1741  */
1742  span_pointer = start_pointer;
1743  }
1744 
1745  /* Initialize span and pagemap. */
1746  init_span(area, span_pointer, pool, start_pointer, npages, size_class);
1747  for (i = 0; i < npages; ++i)
1748  segment_map->pagemap[first_page + i] = span_pointer;
1749 
1750  return true;
1751 }
#define DSA_PAGES_PER_SUPERBLOCK
Definition: dsa.c:104

References alloc_object(), Assert(), DSA_AREA_LOCK, DSA_FULLNESS_CLASSES, dsa_get_address(), DSA_MAKE_POINTER, DSA_PAGES_PER_SUPERBLOCK, DSA_SCLASS_BLOCK_OF_SPANS, DSA_SCLASS_LOCK, dsa_size_classes, DSA_SUPERBLOCK_SIZE, DsaPointerIsValid, elog, FATAL, dsa_area_span::fclass, dsa_segment_map::fpm, FPM_PAGE_SIZE, FreePageManagerGet(), get_best_segment(), get_segment_index, i, init_span(), InvalidDsaPointer, LW_EXCLUSIVE, LWLockAcquire(), LWLockHeldByMe(), LWLockRelease(), make_new_segment(), dsa_area_span::nallocatable, dsa_area_span::nextspan, dsa_segment_map::pagemap, dsa_area_span::prevspan, dsa_area_pool::spans, and transfer_first_span().

Referenced by alloc_object().

◆ get_best_segment()

static dsa_segment_map * get_best_segment ( dsa_area area,
size_t  npages 
)
static

Definition at line 2015 of file dsa.c.

2016 {
2017  size_t bin;
2018 
2021 
2022  /*
2023  * Start searching from the first bin that *might* have enough contiguous
2024  * pages.
2025  */
2026  for (bin = contiguous_pages_to_segment_bin(npages);
2027  bin < DSA_NUM_SEGMENT_BINS;
2028  ++bin)
2029  {
2030  /*
2031  * The minimum contiguous size that any segment in this bin should
2032  * have. We'll re-bin if we see segments with fewer.
2033  */
2034  size_t threshold = (size_t) 1 << (bin - 1);
2035  dsa_segment_index segment_index;
2036 
2037  /* Search this bin for a segment with enough contiguous space. */
2038  segment_index = area->control->segment_bins[bin];
2039  while (segment_index != DSA_SEGMENT_INDEX_NONE)
2040  {
2041  dsa_segment_map *segment_map;
2042  dsa_segment_index next_segment_index;
2043  size_t contiguous_pages;
2044 
2045  segment_map = get_segment_by_index(area, segment_index);
2046  next_segment_index = segment_map->header->next;
2047  contiguous_pages = fpm_largest(segment_map->fpm);
2048 
2049  /* Not enough for the request, still enough for this bin. */
2050  if (contiguous_pages >= threshold && contiguous_pages < npages)
2051  {
2052  segment_index = next_segment_index;
2053  continue;
2054  }
2055 
2056  /* Re-bin it if it's no longer in the appropriate bin. */
2057  if (contiguous_pages < threshold)
2058  {
2059  rebin_segment(area, segment_map);
2060 
2061  /*
2062  * But fall through to see if it's enough to satisfy this
2063  * request anyway....
2064  */
2065  }
2066 
2067  /* Check if we are done. */
2068  if (contiguous_pages >= npages)
2069  return segment_map;
2070 
2071  /* Continue searching the same bin. */
2072  segment_index = next_segment_index;
2073  }
2074  }
2075 
2076  /* Not found. */
2077  return NULL;
2078 }

References Assert(), check_for_freed_segments_locked(), contiguous_pages_to_segment_bin(), dsa_area::control, DSA_AREA_LOCK, DSA_NUM_SEGMENT_BINS, DSA_SEGMENT_INDEX_NONE, dsa_segment_map::fpm, fpm_largest, get_segment_by_index(), dsa_segment_map::header, LWLockHeldByMe(), dsa_segment_header::next, rebin_segment(), and dsa_area_control::segment_bins.

Referenced by dsa_allocate_extended(), and ensure_active_superblock().

◆ get_segment_by_index()

static dsa_segment_map * get_segment_by_index ( dsa_area area,
dsa_segment_index  index 
)
static

Definition at line 1762 of file dsa.c.

1763 {
1764  if (unlikely(area->segment_maps[index].mapped_address == NULL))
1765  {
1766  dsm_handle handle;
1767  dsm_segment *segment;
1768  dsa_segment_map *segment_map;
1769  ResourceOwner oldowner;
1770 
1771  /*
1772  * If we are reached by dsa_free or dsa_get_address, there must be at
1773  * least one object allocated in the referenced segment. Otherwise,
1774  * their caller has a double-free or access-after-free bug, which we
1775  * have no hope of detecting. So we know it's safe to access this
1776  * array slot without holding a lock; it won't change underneath us.
1777  * Furthermore, we know that we can see the latest contents of the
1778  * slot, as explained in check_for_freed_segments, which those
1779  * functions call before arriving here.
1780  */
1781  handle = area->control->segment_handles[index];
1782 
1783  /* It's an error to try to access an unused slot. */
1784  if (handle == DSM_HANDLE_INVALID)
1785  elog(ERROR,
1786  "dsa_area could not attach to a segment that has been freed");
1787 
1788  oldowner = CurrentResourceOwner;
1790  segment = dsm_attach(handle);
1791  CurrentResourceOwner = oldowner;
1792  if (segment == NULL)
1793  elog(ERROR, "dsa_area could not attach to segment");
1794  segment_map = &area->segment_maps[index];
1795  segment_map->segment = segment;
1796  segment_map->mapped_address = dsm_segment_address(segment);
1797  segment_map->header =
1798  (dsa_segment_header *) segment_map->mapped_address;
1799  segment_map->fpm = (FreePageManager *)
1800  (segment_map->mapped_address +
1801  MAXALIGN(sizeof(dsa_segment_header)));
1802  segment_map->pagemap = (dsa_pointer *)
1803  (segment_map->mapped_address +
1804  MAXALIGN(sizeof(dsa_segment_header)) +
1805  MAXALIGN(sizeof(FreePageManager)));
1806 
1807  /* Remember the highest index this backend has ever mapped. */
1808  if (area->high_segment_index < index)
1809  area->high_segment_index = index;
1810 
1811  Assert(segment_map->header->magic ==
1813  }
1814 
1815  /*
1816  * Callers of dsa_get_address() and dsa_free() don't hold the area lock,
1817  * but it's a bug in the calling code and undefined behavior if the
1818  * address is not live (ie if the segment might possibly have been freed,
1819  * they're trying to use a dangling pointer).
1820  *
1821  * For dsa.c code that holds the area lock to manipulate segment_bins
1822  * lists, it would be a bug if we ever reach a freed segment here. After
1823  * it's marked as freed, the only thing any backend should do with it is
1824  * unmap it, and it should always have done that in
1825  * check_for_freed_segments_locked() before arriving here to resolve an
1826  * index to a segment_map.
1827  *
1828  * Either way we can assert that we aren't returning a freed segment.
1829  */
1830  Assert(!area->segment_maps[index].header->freed);
1831 
1832  return &area->segment_maps[index];
1833 }

References Assert(), dsa_area::control, CurrentResourceOwner, DSA_SEGMENT_HEADER_MAGIC, dsm_attach(), DSM_HANDLE_INVALID, dsm_segment_address(), elog, ERROR, dsa_segment_map::fpm, dsa_segment_header::freed, dsa_area_control::handle, dsa_segment_map::header, dsa_area::high_segment_index, dsa_segment_header::magic, dsa_segment_map::mapped_address, MAXALIGN, dsa_segment_map::pagemap, dsa_area::resowner, dsa_segment_map::segment, dsa_area_control::segment_handles, dsa_area::segment_maps, and unlikely.

Referenced by destroy_superblock(), dsa_dump(), dsa_free(), dsa_get_address(), get_best_segment(), make_new_segment(), rebin_segment(), and unlink_segment().

◆ init_span()

static void init_span ( dsa_area area,
dsa_pointer  span_pointer,
dsa_area_pool pool,
dsa_pointer  start,
size_t  npages,
uint16  size_class 
)
static

Definition at line 1382 of file dsa.c.

1386 {
1387  dsa_area_span *span = dsa_get_address(area, span_pointer);
1388  size_t obsize = dsa_size_classes[size_class];
1389 
1390  /*
1391  * The per-pool lock must be held because we manipulate the span list for
1392  * this pool.
1393  */
1394  Assert(LWLockHeldByMe(DSA_SCLASS_LOCK(area, size_class)));
1395 
1396  /* Push this span onto the front of the span list for fullness class 1. */
1397  if (DsaPointerIsValid(pool->spans[1]))
1398  {
1399  dsa_area_span *head = (dsa_area_span *)
1400  dsa_get_address(area, pool->spans[1]);
1401 
1402  head->prevspan = span_pointer;
1403  }
1404  span->pool = DsaAreaPoolToDsaPointer(area, pool);
1405  span->nextspan = pool->spans[1];
1406  span->prevspan = InvalidDsaPointer;
1407  pool->spans[1] = span_pointer;
1408 
1409  span->start = start;
1410  span->npages = npages;
1411  span->size_class = size_class;
1412  span->ninitialized = 0;
1413  if (size_class == DSA_SCLASS_BLOCK_OF_SPANS)
1414  {
1415  /*
1416  * A block-of-spans contains its own descriptor, so mark one object as
1417  * initialized and reduce the count of allocatable objects by one.
1418  * Doing this here has the side effect of also reducing nmax by one,
1419  * which is important to make sure we free this object at the correct
1420  * time.
1421  */
1422  span->ninitialized = 1;
1423  span->nallocatable = FPM_PAGE_SIZE / obsize - 1;
1424  }
1425  else if (size_class != DSA_SCLASS_SPAN_LARGE)
1426  span->nallocatable = DSA_SUPERBLOCK_SIZE / obsize;
1428  span->nmax = span->nallocatable;
1429  span->fclass = 1;
1430 }
#define DsaAreaPoolToDsaPointer(area, p)
Definition: dsa.c:340

References Assert(), dsa_get_address(), DSA_SCLASS_BLOCK_OF_SPANS, DSA_SCLASS_LOCK, DSA_SCLASS_SPAN_LARGE, dsa_size_classes, DSA_SPAN_NOTHING_FREE, DSA_SUPERBLOCK_SIZE, DsaAreaPoolToDsaPointer, DsaPointerIsValid, dsa_area_span::fclass, dsa_area_span::firstfree, FPM_PAGE_SIZE, InvalidDsaPointer, LWLockHeldByMe(), dsa_area_span::nallocatable, dsa_area_span::nextspan, dsa_area_span::ninitialized, dsa_area_span::nmax, dsa_area_span::npages, dsa_area_span::pool, dsa_area_span::prevspan, dsa_area_span::size_class, dsa_area_pool::spans, and dsa_area_span::start.

Referenced by dsa_allocate_extended(), and ensure_active_superblock().

◆ make_new_segment()

static dsa_segment_map * make_new_segment ( dsa_area area,
size_t  requested_pages 
)
static

Definition at line 2086 of file dsa.c.

2087 {
2088  dsa_segment_index new_index;
2089  size_t metadata_bytes;
2090  size_t total_size;
2091  size_t total_pages;
2092  size_t usable_pages;
2093  dsa_segment_map *segment_map;
2094  dsm_segment *segment;
2095  ResourceOwner oldowner;
2096 
2098 
2099  /* Find a segment slot that is not in use (linearly for now). */
2100  for (new_index = 1; new_index < DSA_MAX_SEGMENTS; ++new_index)
2101  {
2102  if (area->control->segment_handles[new_index] == DSM_HANDLE_INVALID)
2103  break;
2104  }
2105  if (new_index == DSA_MAX_SEGMENTS)
2106  return NULL;
2107 
2108  /*
2109  * If the total size limit is already exceeded, then we exit early and
2110  * avoid arithmetic wraparound in the unsigned expressions below.
2111  */
2112  if (area->control->total_segment_size >=
2114  return NULL;
2115 
2116  /*
2117  * The size should be at least as big as requested, and at least big
2118  * enough to follow a geometric series that approximately doubles the
2119  * total storage each time we create a new segment. We use geometric
2120  * growth because the underlying DSM system isn't designed for large
2121  * numbers of segments (otherwise we might even consider just using one
2122  * DSM segment for each large allocation and for each superblock, and then
2123  * we wouldn't need to use FreePageManager).
2124  *
2125  * We decide on a total segment size first, so that we produce tidy
2126  * power-of-two sized segments. This is a good property to have if we
2127  * move to huge pages in the future. Then we work back to the number of
2128  * pages we can fit.
2129  */
2131  ((size_t) 1 << (new_index / DSA_NUM_SEGMENTS_AT_EACH_SIZE));
2135  area->control->total_segment_size);
2136 
2137  total_pages = total_size / FPM_PAGE_SIZE;
2138  metadata_bytes =
2139  MAXALIGN(sizeof(dsa_segment_header)) +
2140  MAXALIGN(sizeof(FreePageManager)) +
2141  sizeof(dsa_pointer) * total_pages;
2142 
2143  /* Add padding up to next page boundary. */
2144  if (metadata_bytes % FPM_PAGE_SIZE != 0)
2145  metadata_bytes += FPM_PAGE_SIZE - (metadata_bytes % FPM_PAGE_SIZE);
2146  if (total_size <= metadata_bytes)
2147  return NULL;
2148  usable_pages = (total_size - metadata_bytes) / FPM_PAGE_SIZE;
2149  Assert(metadata_bytes + usable_pages * FPM_PAGE_SIZE <= total_size);
2150 
2151  /* See if that is enough... */
2152  if (requested_pages > usable_pages)
2153  {
2154  /*
2155  * We'll make an odd-sized segment, working forward from the requested
2156  * number of pages.
2157  */
2158  usable_pages = requested_pages;
2159  metadata_bytes =
2160  MAXALIGN(sizeof(dsa_segment_header)) +
2161  MAXALIGN(sizeof(FreePageManager)) +
2162  usable_pages * sizeof(dsa_pointer);
2163 
2164  /* Add padding up to next page boundary. */
2165  if (metadata_bytes % FPM_PAGE_SIZE != 0)
2166  metadata_bytes += FPM_PAGE_SIZE - (metadata_bytes % FPM_PAGE_SIZE);
2167  total_size = metadata_bytes + usable_pages * FPM_PAGE_SIZE;
2168 
2169  /* Is that too large for dsa_pointer's addressing scheme? */
2171  return NULL;
2172 
2173  /* Would that exceed the limit? */
2175  area->control->total_segment_size)
2176  return NULL;
2177  }
2178 
2179  /* Create the segment. */
2180  oldowner = CurrentResourceOwner;
2182  segment = dsm_create(total_size, 0);
2183  CurrentResourceOwner = oldowner;
2184  if (segment == NULL)
2185  return NULL;
2186  dsm_pin_segment(segment);
2187 
2188  /* Store the handle in shared memory to be found by index. */
2189  area->control->segment_handles[new_index] =
2190  dsm_segment_handle(segment);
2191  /* Track the highest segment index in the history of the area. */
2192  if (area->control->high_segment_index < new_index)
2193  area->control->high_segment_index = new_index;
2194  /* Track the highest segment index this backend has ever mapped. */
2195  if (area->high_segment_index < new_index)
2196  area->high_segment_index = new_index;
2197  /* Track total size of all segments. */
2201 
2202  /* Build a segment map for this segment in this backend. */
2203  segment_map = &area->segment_maps[new_index];
2204  segment_map->segment = segment;
2205  segment_map->mapped_address = dsm_segment_address(segment);
2206  segment_map->header = (dsa_segment_header *) segment_map->mapped_address;
2207  segment_map->fpm = (FreePageManager *)
2208  (segment_map->mapped_address +
2209  MAXALIGN(sizeof(dsa_segment_header)));
2210  segment_map->pagemap = (dsa_pointer *)
2211  (segment_map->mapped_address +
2212  MAXALIGN(sizeof(dsa_segment_header)) +
2213  MAXALIGN(sizeof(FreePageManager)));
2214 
2215  /* Set up the free page map. */
2216  FreePageManagerInitialize(segment_map->fpm, segment_map->mapped_address);
2217  FreePageManagerPut(segment_map->fpm, metadata_bytes / FPM_PAGE_SIZE,
2218  usable_pages);
2219 
2220  /* Set up the segment header and put it in the appropriate bin. */
2221  segment_map->header->magic =
2222  DSA_SEGMENT_HEADER_MAGIC ^ area->control->handle ^ new_index;
2223  segment_map->header->usable_pages = usable_pages;
2224  segment_map->header->size = total_size;
2225  segment_map->header->bin = contiguous_pages_to_segment_bin(usable_pages);
2226  segment_map->header->prev = DSA_SEGMENT_INDEX_NONE;
2227  segment_map->header->next =
2228  area->control->segment_bins[segment_map->header->bin];
2229  segment_map->header->freed = false;
2230  area->control->segment_bins[segment_map->header->bin] = new_index;
2231  if (segment_map->header->next != DSA_SEGMENT_INDEX_NONE)
2232  {
2234  get_segment_by_index(area, segment_map->header->next);
2235 
2236  Assert(next->header->bin == segment_map->header->bin);
2237  next->header->prev = new_index;
2238  }
2239 
2240  return segment_map;
2241 }
#define DSA_NUM_SEGMENTS_AT_EACH_SIZE
Definition: dsa.c:77
#define DSA_MAX_SEGMENT_SIZE
Definition: dsa.c:101
int64 total_size
Definition: pg_checksums.c:63

References Assert(), dsa_segment_header::bin, contiguous_pages_to_segment_bin(), dsa_area::control, CurrentResourceOwner, DSA_AREA_LOCK, DSA_INITIAL_SEGMENT_SIZE, DSA_MAX_SEGMENT_SIZE, DSA_MAX_SEGMENTS, DSA_NUM_SEGMENTS_AT_EACH_SIZE, DSA_SEGMENT_HEADER_MAGIC, DSA_SEGMENT_INDEX_NONE, dsm_create(), DSM_HANDLE_INVALID, dsm_pin_segment(), dsm_segment_address(), dsm_segment_handle(), dsa_segment_map::fpm, FPM_PAGE_SIZE, dsa_segment_header::freed, FreePageManagerInitialize(), FreePageManagerPut(), get_segment_by_index(), dsa_area_control::handle, dsa_segment_map::header, dsa_area_control::high_segment_index, dsa_area::high_segment_index, LWLockHeldByMe(), dsa_segment_header::magic, dsa_segment_map::mapped_address, dsa_area_control::max_total_segment_size, MAXALIGN, Min, next, dsa_segment_header::next, dsa_segment_map::pagemap, dsa_segment_header::prev, dsa_area::resowner, dsa_segment_map::segment, dsa_area_control::segment_bins, dsa_area_control::segment_handles, dsa_area::segment_maps, dsa_segment_header::size, dsa_area_control::total_segment_size, total_size, and dsa_segment_header::usable_pages.

Referenced by dsa_allocate_extended(), and ensure_active_superblock().

◆ rebin_segment()

static void rebin_segment ( dsa_area area,
dsa_segment_map segment_map 
)
static

Definition at line 2321 of file dsa.c.

2322 {
2323  size_t new_bin;
2324  dsa_segment_index segment_index;
2325 
2326  new_bin = contiguous_pages_to_segment_bin(fpm_largest(segment_map->fpm));
2327  if (segment_map->header->bin == new_bin)
2328  return;
2329 
2330  /* Remove it from its current bin. */
2331  unlink_segment(area, segment_map);
2332 
2333  /* Push it onto the front of its new bin. */
2334  segment_index = get_segment_index(area, segment_map);
2335  segment_map->header->prev = DSA_SEGMENT_INDEX_NONE;
2336  segment_map->header->next = area->control->segment_bins[new_bin];
2337  segment_map->header->bin = new_bin;
2338  area->control->segment_bins[new_bin] = segment_index;
2339  if (segment_map->header->next != DSA_SEGMENT_INDEX_NONE)
2340  {
2342 
2343  next = get_segment_by_index(area, segment_map->header->next);
2344  Assert(next->header->bin == new_bin);
2345  next->header->prev = segment_index;
2346  }
2347 }

References Assert(), dsa_segment_header::bin, contiguous_pages_to_segment_bin(), dsa_area::control, DSA_SEGMENT_INDEX_NONE, dsa_segment_map::fpm, fpm_largest, get_segment_by_index(), get_segment_index, dsa_segment_map::header, next, dsa_segment_header::next, dsa_segment_header::prev, dsa_area_control::segment_bins, and unlink_segment().

Referenced by destroy_superblock(), dsa_free(), and get_best_segment().

◆ transfer_first_span()

static bool transfer_first_span ( dsa_area area,
dsa_area_pool pool,
int  fromclass,
int  toclass 
)
static

Definition at line 1437 of file dsa.c.

1439 {
1440  dsa_pointer span_pointer;
1441  dsa_area_span *span;
1442  dsa_area_span *nextspan;
1443 
1444  /* Can't do it if source list is empty. */
1445  span_pointer = pool->spans[fromclass];
1446  if (!DsaPointerIsValid(span_pointer))
1447  return false;
1448 
1449  /* Remove span from head of source list. */
1450  span = dsa_get_address(area, span_pointer);
1451  pool->spans[fromclass] = span->nextspan;
1452  if (DsaPointerIsValid(span->nextspan))
1453  {
1454  nextspan = (dsa_area_span *)
1455  dsa_get_address(area, span->nextspan);
1456  nextspan->prevspan = InvalidDsaPointer;
1457  }
1458 
1459  /* Add span to head of target list. */
1460  span->nextspan = pool->spans[toclass];
1461  pool->spans[toclass] = span_pointer;
1462  if (DsaPointerIsValid(span->nextspan))
1463  {
1464  nextspan = (dsa_area_span *)
1465  dsa_get_address(area, span->nextspan);
1466  nextspan->prevspan = span_pointer;
1467  }
1468  span->fclass = toclass;
1469 
1470  return true;
1471 }

References dsa_get_address(), DsaPointerIsValid, dsa_area_span::fclass, InvalidDsaPointer, dsa_area_span::nextspan, dsa_area_span::prevspan, and dsa_area_pool::spans.

Referenced by alloc_object(), and ensure_active_superblock().

◆ unlink_segment()

static void unlink_segment ( dsa_area area,
dsa_segment_map segment_map 
)
static

Definition at line 1983 of file dsa.c.

1984 {
1985  if (segment_map->header->prev != DSA_SEGMENT_INDEX_NONE)
1986  {
1987  dsa_segment_map *prev;
1988 
1989  prev = get_segment_by_index(area, segment_map->header->prev);
1990  prev->header->next = segment_map->header->next;
1991  }
1992  else
1993  {
1994  Assert(area->control->segment_bins[segment_map->header->bin] ==
1995  get_segment_index(area, segment_map));
1996  area->control->segment_bins[segment_map->header->bin] =
1997  segment_map->header->next;
1998  }
1999  if (segment_map->header->next != DSA_SEGMENT_INDEX_NONE)
2000  {
2002 
2003  next = get_segment_by_index(area, segment_map->header->next);
2004  next->header->prev = segment_map->header->prev;
2005  }
2006 }

References Assert(), dsa_segment_header::bin, dsa_area::control, DSA_SEGMENT_INDEX_NONE, get_segment_by_index(), get_segment_index, dsa_segment_map::header, next, dsa_segment_header::next, dsa_segment_header::prev, and dsa_area_control::segment_bins.

Referenced by destroy_superblock(), and rebin_segment().

◆ unlink_span()

static void unlink_span ( dsa_area area,
dsa_area_span span 
)
static

Definition at line 1911 of file dsa.c.

1912 {
1913  if (DsaPointerIsValid(span->nextspan))
1914  {
1915  dsa_area_span *next = dsa_get_address(area, span->nextspan);
1916 
1917  next->prevspan = span->prevspan;
1918  }
1919  if (DsaPointerIsValid(span->prevspan))
1920  {
1921  dsa_area_span *prev = dsa_get_address(area, span->prevspan);
1922 
1923  prev->nextspan = span->nextspan;
1924  }
1925  else
1926  {
1927  dsa_area_pool *pool = dsa_get_address(area, span->pool);
1928 
1929  pool->spans[span->fclass] = span->nextspan;
1930  }
1931 }

References dsa_get_address(), DsaPointerIsValid, dsa_area_span::fclass, next, dsa_area_span::nextspan, dsa_area_span::pool, dsa_area_span::prevspan, and dsa_area_pool::spans.

Referenced by destroy_superblock(), and dsa_free().

Variable Documentation

◆ dsa_size_class_map

const uint8 dsa_size_class_map[]
static
Initial value:
= {
2, 3, 4, 5, 6, 7, 8, 9, 10, 10, 11, 11, 12, 12, 13, 13,
14, 14, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 17, 17, 17, 17,
18, 18, 18, 18, 18, 18, 18, 18, 19, 19, 19, 19, 19, 19, 19, 19,
20, 20, 20, 20, 20, 20, 20, 20, 21, 21, 21, 21, 21, 21, 21, 21,
22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22,
23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23,
24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25
}

Definition at line 270 of file dsa.c.

Referenced by dsa_allocate_extended().

◆ dsa_size_classes

const uint16 dsa_size_classes[]
static
Initial value:
= {
sizeof(dsa_area_span), 0,
8, 16, 24, 32, 40, 48, 56, 64,
80, 96, 112, 128,
160, 192, 224, 256,
320, 384, 448, 512,
640, 768, 896, 1024,
1280, 1560, 1816, 2048,
2616, 3120, 3640, 4096,
5456, 6552, 7280, 8192
}

Definition at line 247 of file dsa.c.

Referenced by alloc_object(), dsa_allocate_extended(), dsa_dump(), dsa_free(), ensure_active_superblock(), and init_span().