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livetrax/libs/pbd/reallocpool.cc
Robin Gareus 6cf5e989c0 time-bound memory-pool
O(1) realloc() for use with Lua.
A standard malloc/free/realloc API is exposed for testing and other
potential use-cases.

The current configuration it's performs well for lua-metatables
(regular calls to realloc() with varying tiny chunks ~1-50 bytes)
For the use-case at hand it outperforms TLSF.
2016-02-22 22:06:47 +01:00

454 lines
10 KiB
C++

/*
* Copyright (C) 2016 Robin Gareus <robin@gareus.org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <stdlib.h>
#include <string.h>
#ifndef PLATFORM_WINDOWS
#include <sys/mman.h>
#endif
#include "pbd/reallocpool.h"
#if defined RAP_WITH_SEGMENT_STATS || defined RAP_WITH_CALL_STATS
#include <cstdio>
#endif
#ifdef RAP_WITH_SEGMENT_STATS
#define STATS_segment collect_segment_stats();
#else
#define STATS_segment
#endif
#ifdef RAP_WITH_CALL_STATS
#define STATS_inc(VAR) ++VAR;
#define STATS_if(COND, VAR) if (COND) {++VAR;}
#define STATS_used(DELTA) { _cur_used += (DELTA); if (_cur_used > _max_used) { _max_used = _cur_used; } }
#else
#define STATS_inc(VAR)
#define STATS_if(COND, VAR)
#define STATS_used(DELTA)
#endif
#ifdef RAP_WITH_HISTOGRAM
#define STATS_hist(VAR, SIZE) ++VAR[hist_bin(SIZE)];
#else
#define STATS_hist(VAR, SIZE)
#endif
using namespace PBD;
typedef int poolsize_t;
ReallocPool::ReallocPool (std::string name, size_t bytes)
: _name (name)
, _poolsize (bytes)
, _pool (0)
#ifdef RAP_WITH_SEGMENT_STATS
, _cur_avail (0)
, _cur_allocated (0)
, _max_allocated (0)
, _seg_cur_count (0)
, _seg_max_count (0)
, _seg_max_used (0)
, _seg_max_avail (0)
#endif
#ifdef RAP_WITH_CALL_STATS
, _n_alloc (0)
, _n_grow (0)
, _n_shrink (0)
, _n_free (0)
, _n_noop (0)
, _n_oom (0)
, _cur_used (0)
, _max_used (0)
#endif
{
_pool = (char*) ::malloc (bytes);
memset (_pool, 0, bytes); // make resident
#ifndef PLATFORM_WINDOWS
mlock (_pool, bytes);
#endif
poolsize_t *in = (poolsize_t*) _pool;
*in = - (bytes - sizeof (poolsize_t));
_mru = _pool;
#ifdef RAP_WITH_HISTOGRAM
for (int i = 0; i < RAP_WITH_HISTOGRAM; ++i) {
_hist_alloc[i] = _hist_free[i] = _hist_grow[i] = _hist_shrink[i] = 0;
}
#endif
}
ReallocPool::~ReallocPool ()
{
STATS_segment;
printstats ();
::free (_pool);
_pool = NULL;
}
// realloc() does it all, malloc(), realloc() and free()
void *
ReallocPool::_realloc (void *ptr, size_t oldsize, size_t newsize) {
void *rv = NULL;
if (ptr == 0 && newsize == 0) {
STATS_inc(_n_noop);
return NULL;
}
if (ptr == 0) {
rv = _malloc (newsize);
STATS_if (!rv, _n_oom);
STATS_inc(_n_alloc);
STATS_hist(_hist_alloc, newsize);
STATS_segment;
return rv;
}
if (newsize == 0) {
STATS_hist(_hist_free, _asize(ptr));
STATS_inc(_n_free);
STATS_segment;
_free (ptr);
return NULL;
}
if (newsize == oldsize) {
STATS_inc(_n_noop);
return ptr;
}
if (newsize > oldsize) {
#ifdef RAP_BLOCKSIZE
const size_t ns = (newsize + RAP_BLOCKSIZE) & (~RAP_BLOCKSIZE);
if (ns <= _asize(ptr)) {
STATS_inc(_n_noop);
return ptr;
}
#endif
if ((rv = _malloc (newsize))) {
memcpy (rv, ptr, oldsize);
}
_free (ptr);
STATS_if(!rv, _n_oom);
STATS_inc(_n_grow);
STATS_hist(_hist_grow, newsize);
STATS_segment;
return rv;
}
if (newsize < oldsize) {
#if 0 // re-allocate
if ((rv = _malloc (newsize))) {
memccpy (rv, ptr, newsize);
}
STATS_if(!rv, _n_oom);
_free (ptr);
#elif 1 // shrink current segment
const size_t ns = (newsize + RAP_BLOCKSIZE) & (~RAP_BLOCKSIZE);
_shrink (ptr, ns);
rv = ptr;
#else // do nothing
rv = ptr;
#endif
STATS_inc(_n_shrink);
STATS_hist (_hist_shrink, newsize);
STATS_segment;
return rv;
}
return NULL; // not reached
}
#define SEGSIZ (*((poolsize_t*) p))
void
ReallocPool::consolidate_ptr (char *p) {
const poolsize_t sop = sizeof(poolsize_t);
if (p - SEGSIZ + sop >= _pool + _poolsize) {
return; // reached end
}
poolsize_t *next = (poolsize_t*)(p - SEGSIZ + sop);
while (*next < 0) {
SEGSIZ = SEGSIZ + (*next) - sop;
if (p - SEGSIZ + sop >= _pool + _poolsize) {
break;
}
next = (poolsize_t*)(p -SEGSIZ + sop);
}
_mru = p;
}
void *
ReallocPool::_malloc (size_t s) {
const poolsize_t sop = sizeof(poolsize_t);
size_t traversed = 0;
char *p = _mru;
#ifdef RAP_BLOCKSIZE
s = (s + RAP_BLOCKSIZE) & (~RAP_BLOCKSIZE); // optional, helps to reduce fragmentation
#endif
while (1) { // iterates at most once over the available pool
while (SEGSIZ > 0) {
traversed += SEGSIZ + sop;
if (traversed >= _poolsize) {
return NULL; // reached last segment. OOM.
}
p += SEGSIZ + sop;
if (p == _pool + _poolsize) {
p = _pool;
}
}
// found free segment.
const poolsize_t avail = -SEGSIZ;
const poolsize_t sp = (poolsize_t)s;
const poolsize_t ss = sop + s;
if (sp == avail) {
// exact match
SEGSIZ = -SEGSIZ;
STATS_used (s);
return (p + sop);
}
if (ss < avail) {
// segment is larger than required space,
// (we need to fit data + two non-zero poolsize_t)
SEGSIZ = sp; // mark area as used.
*((poolsize_t*)(p + ss)) = ss - avail; // mark free space after.
consolidate_ptr (p + ss);
_mru = p + ss;
STATS_used (s);
return (p + sop);
}
// segment is not large enough
consolidate_ptr (p); // try to consolidate with next segment (if any)
// check segment (again) and skip over too small free ones
while (SEGSIZ < 0 && (-SEGSIZ) <= ss && (-SEGSIZ) != sp) {
traversed += -SEGSIZ + sop;
if (traversed >= _poolsize) {
return NULL; // reached last segment. OOM.
}
p += (-SEGSIZ) + sop;
if (p >= _pool + _poolsize) {
p = _pool;
if (SEGSIZ < 0) consolidate_ptr (p);
}
}
}
}
#undef SEGSIZ
void
ReallocPool::_free (void *ptr) {
poolsize_t *in = (poolsize_t*) ptr;
--in;
*in = -*in; // mark as free
//_mru = p + ss;
STATS_used (*in);
}
void
ReallocPool::_shrink (void *ptr, size_t newsize) {
poolsize_t *in = (poolsize_t*) ptr;
--in;
const poolsize_t avail = *in;
const poolsize_t ss = newsize + sizeof(poolsize_t);
if (avail <= ss) {
return; // can't shrink
}
const poolsize_t sp = (poolsize_t)newsize;
STATS_used (newsize - avail);
*in = sp; // set new size
char *p = (char*) in;
*((poolsize_t*)(p + ss)) = ss - avail; // mark free space after.
//_mru = p + ss;
}
size_t
ReallocPool::_asize (void *ptr) {
if (ptr == 0) return 0;
poolsize_t *in = (poolsize_t*) ptr;
--in;
return (*in);
}
/** STATS **/
void
ReallocPool::printstats ()
{
#ifdef RAP_WITH_SEGMENT_STATS
printf ("ReallocPool '%s': used: %ld (%.1f%%) (max: %ld), free: %ld [bytes]\n"
"|| segments: cur: %ld (max: %ld), largest-used: %ld, largest-free: %ld\n",
_name.c_str(),
_cur_allocated, _cur_allocated * 100.f / _poolsize, _max_allocated, _cur_avail,
_seg_cur_count, _seg_max_count, _seg_max_used, _seg_max_avail);
#elif defined RAP_WITH_CALL_STATS
printf ("ReallocPool '%s':\n", _name.c_str());
#endif
#ifdef RAP_WITH_CALL_STATS
printf("|| malloc(): %ld, free(): %ld, realloc()+:%ld, realloc()-: %ld NOOP:%ld OOM:%ld\n",
_n_alloc, _n_free, _n_grow, _n_shrink, _n_noop, _n_oom);
printf("|| used: %ld / %ld, max: %ld (%.1f%%)\n",
_cur_used, _poolsize,
_max_used, 100.f *_max_used / _poolsize);
#endif
#ifdef RAP_WITH_HISTOGRAM
printf("--- malloc()\n");
print_histogram (_hist_alloc);
printf("--- realloc()/grow-to\n");
print_histogram (_hist_grow);
printf("--- realloc()/shrink-to\n");
print_histogram (_hist_shrink);
printf("--- free() histogram\n");
print_histogram (_hist_free);
printf("--------------------\n");
#endif
}
void
ReallocPool::dumpsegments ()
{
char *p = _pool;
const poolsize_t sop = sizeof(poolsize_t);
poolsize_t *in = (poolsize_t*) p;
unsigned int traversed = 0;
printf ("<<<<< %s\n", _name.c_str());
while (1) {
if ((*in) > 0) {
printf ("0x%08x used %4d\n", traversed, *in);
printf ("0x%08x data %p\n", traversed + sop , p + sop);
traversed += *in + sop;
p += *in + sop;
} else if ((*in) < 0) {
printf ("0x%08x free %4d [+%d]\n", traversed, -*in, sop);
traversed += -*in + sop;
p += -*in + sop;
} else {
printf ("0x%08x Corrupt!\n", traversed);
break;
}
in = (poolsize_t*) p;
if (p == _pool + _poolsize) {
printf ("%08x end\n", traversed);
break;
}
if (p > _pool + _poolsize) {
printf ("%08x Beyond End!\n", traversed);
break;
}
}
printf (">>>>>\n");
}
#ifdef RAP_WITH_SEGMENT_STATS
void
ReallocPool::collect_segment_stats ()
{
char *p = _pool;
poolsize_t *in = (poolsize_t*) p;
_cur_allocated = _cur_avail = 0;
_seg_cur_count = _seg_max_avail = _seg_max_used = 0;
while (1) {
++_seg_cur_count;
if ((*in) > 0) {
_cur_allocated += *in;
p += *in;
if (*in > (poolsize_t)_seg_max_used) {
_seg_max_used = *in;
}
} else {
_cur_avail += -*in;
p += -*in;
if (-*in > (poolsize_t)_seg_max_avail) {
_seg_max_avail = -*in;
}
}
p += sizeof(poolsize_t);
in = (poolsize_t*) p;
if (p == _pool + _poolsize) {
break;
}
}
_seg_cur_count = _seg_cur_count;
if (_cur_allocated > _max_allocated) {
_max_allocated = _cur_allocated;
}
if (_seg_cur_count > _seg_max_count) {
_seg_max_count = _seg_cur_count;
}
}
#endif
#ifdef RAP_WITH_HISTOGRAM
void
ReallocPool::print_histogram (size_t const * const histogram) const
{
size_t maxhist = 0;
for (int i = 0; i < RAP_WITH_HISTOGRAM; ++i) {
if (histogram[i] > maxhist) maxhist = histogram[i];
}
const int termwidth = 50;
#ifdef RAP_BLOCKSIZE
const int fact = RAP_BLOCKSIZE + 1;
#endif
if (maxhist > 0) for (int i = 0; i < RAP_WITH_HISTOGRAM; ++i) {
if (histogram[i] == 0) { continue; }
if (i == RAP_WITH_HISTOGRAM -1 ) {
#ifdef RAP_BLOCKSIZE
printf(" > %4d: %7lu ", i * fact, histogram[i]);
#else
printf(">%4d:%7lu ", i * fact, histogram[i]);
#endif
} else {
#ifdef RAP_BLOCKSIZE
printf("%4d .. %4d: %7lu ", i * fact, (i + 1) * fact -1, histogram[i]);
#else
printf("%4d: %7lu ", i * fact, (i + 1) * fact -1 , histogram[i]);
#endif
}
int bar_width = (histogram[i] * termwidth ) / maxhist;
if (bar_width == 0 && histogram[i] > 0) bar_width = 1;
for (int j = 0; j < bar_width; ++j) printf("#");
printf("\n");
}
}
unsigned int
ReallocPool::hist_bin (size_t s) const {
#ifdef RAP_BLOCKSIZE
s = (s + RAP_BLOCKSIZE) & (~RAP_BLOCKSIZE);
s /= (RAP_BLOCKSIZE + 1);
#endif
if (s > RAP_WITH_HISTOGRAM - 1) s = RAP_WITH_HISTOGRAM - 1;
return s;
}
#endif