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livetrax/libs/pbd/pool.cc

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/*
Copyright (C) 1998-99 Paul Barton-Davis
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., 675 Mass Ave, Cambridge, MA 02139, USA.
$Id$
*/
#include <cstdlib>
#include <vector>
#include <cstdlib>
#include <cassert>
#include "pbd/pool.h"
#include "pbd/pthread_utils.h"
#include "pbd/error.h"
#include "pbd/debug.h"
#include "pbd/compose.h"
using namespace std;
using namespace PBD;
Pool::Pool (string n, unsigned long item_size, unsigned long nitems)
: free_list (nitems)
, _name (n)
{
_name = n;
/* since some overloaded ::operator new() might use this,
its important that we use a "lower level" allocator to
get more space.
*/
block = malloc (nitems * item_size);
void **ptrlist = (void **) malloc (sizeof (void *) * nitems);
for (unsigned long i = 0; i < nitems; i++) {
ptrlist[i] = static_cast<void *> (static_cast<char*>(block) + (i * item_size));
}
free_list.write (ptrlist, nitems);
free (ptrlist);
}
Pool::~Pool ()
{
free (block);
}
/** Allocate an item's worth of memory in the Pool by taking one from the free list.
* @return Pointer to free item.
*/
void *
Pool::alloc ()
{
void *ptr;
if (free_list.read (&ptr, 1) < 1) {
fatal << "CRITICAL: " << _name << " POOL OUT OF MEMORY - RECOMPILE WITH LARGER SIZE!!" << endmsg;
abort(); /*NOTREACHED*/
return 0;
} else {
return ptr;
}
}
/** Release an item's memory by writing its location to the free list */
void
Pool::release (void *ptr)
{
free_list.write (&ptr, 1);
}
/*---------------------------------------------*/
MultiAllocSingleReleasePool::MultiAllocSingleReleasePool (string n, unsigned long isize, unsigned long nitems)
: Pool (n, isize, nitems)
{
}
MultiAllocSingleReleasePool::~MultiAllocSingleReleasePool ()
{
}
SingleAllocMultiReleasePool::SingleAllocMultiReleasePool (string n, unsigned long isize, unsigned long nitems)
: Pool (n, isize, nitems)
{
}
SingleAllocMultiReleasePool::~SingleAllocMultiReleasePool ()
{
}
void*
MultiAllocSingleReleasePool::alloc ()
{
void *ptr;
Glib::Threads::Mutex::Lock guard (m_lock);
ptr = Pool::alloc ();
return ptr;
}
void
MultiAllocSingleReleasePool::release (void* ptr)
{
Pool::release (ptr);
}
void*
SingleAllocMultiReleasePool::alloc ()
{
return Pool::alloc ();
}
void
SingleAllocMultiReleasePool::release (void* ptr)
{
Glib::Threads::Mutex::Lock guard (m_lock);
Pool::release (ptr);
}
/*-------------------------------------------------------*/
static void
free_per_thread_pool (void* ptr)
{
/* Rather than deleting the CrossThreadPool now, we add it to our trash buffer.
* This prevents problems if other threads still require access to this CrossThreadPool.
* We assume that some other agent will clean out the trash buffer as required.
*/
CrossThreadPool* cp = static_cast<CrossThreadPool*> (ptr);
assert (cp);
if (cp->empty()) {
/* This CrossThreadPool is already empty, and the thread is finishing so nothing
* more can be added to it. We can just delete the pool.
*/
delete cp;
} else {
/* This CrossThreadPool is not empty, meaning that there's some Events in it
* which another thread may yet read, so we can't delete the pool just yet.
* Put it in the trash and hope someone deals with it at some stage.
*/
cp->parent()->add_to_trash (cp);
}
}
PerThreadPool::PerThreadPool ()
: _key (free_per_thread_pool)
, _trash (0)
{
}
/** Create a new CrossThreadPool and set the current thread's private _key to point to it.
* @param n Name.
* @param isize Size of each item in the pool.
* @param nitems Number of items in the pool.
*/
void
PerThreadPool::create_per_thread_pool (string n, unsigned long isize, unsigned long nitems)
{
_key.set (new CrossThreadPool (n, isize, nitems, this));
}
/** @return True if CrossThreadPool for the current thread exists,
* False otherwise
*/
bool
PerThreadPool::has_per_thread_pool ()
{
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CrossThreadPool* p = _key.get();
if (p) {
return true;
}
return false;
}
/** @return CrossThreadPool for the current thread, which must previously have been created by
* calling create_per_thread_pool in the current thread.
*/
CrossThreadPool*
PerThreadPool::per_thread_pool (bool must_exist)
{
CrossThreadPool* p = _key.get();
if (!p && must_exist) {
fatal << "programming error: no per-thread pool \"" << _name << "\" for thread " << pthread_name() << endmsg;
abort(); /*NOTREACHED*/
}
return p;
}
void
PerThreadPool::set_trash (RingBuffer<CrossThreadPool*>* t)
{
Glib::Threads::Mutex::Lock lm (_trash_mutex);
_trash = t;
}
/** Add a CrossThreadPool to our trash, if we have one. If not, a warning is emitted. */
void
PerThreadPool::add_to_trash (CrossThreadPool* p)
{
Glib::Threads::Mutex::Lock lm (_trash_mutex);
if (!_trash) {
warning << "Pool " << p->name() << " has no trash collector; a memory leak has therefore occurred" << endmsg;
return;
}
/* we have a lock here so that multiple threads can safely call add_to_trash (even though there
can only be one writer to the _trash RingBuffer)
*/
_trash->write (&p, 1);
}
CrossThreadPool::CrossThreadPool (string n, unsigned long isize, unsigned long nitems, PerThreadPool* p)
: Pool (n, isize, nitems)
, pending (nitems)
, _parent (p)
{
}
void
CrossThreadPool::flush_pending_with_ev (void *ptr)
{
push (ptr);
flush_pending ();
}
void
CrossThreadPool::flush_pending ()
{
void* ptr;
bool did_release = false;
DEBUG_TRACE (DEBUG::Pool, string_compose ("%1 %2 has %3 pending free entries waiting, status size %4 free %5 used %6\n", pthread_name(), name(), pending.read_space(),
total(), available(), used()));
while (pending.read (&ptr, 1) == 1) {
DEBUG_TRACE (DEBUG::Pool, string_compose ("%1 %2 pushes back a pending free list entry before allocating\n", pthread_name(), name()));
free_list.write (&ptr, 1);
did_release = true;
}
if (did_release) {
DEBUG_TRACE (DEBUG::Pool, string_compose ("Pool size: %1 free %2 used %3 pending now %4\n", total(), available(), used(), pending_size()));
}
}
void*
CrossThreadPool::alloc ()
{
/* process anything waiting to be deleted (i.e. moved back to the free list) */
flush_pending ();
/* now allocate from the potentially larger free list */
return Pool::alloc ();
}
void
CrossThreadPool::push (void* t)
{
pending.write (&t, 1);
}
/** @return true if there is nothing in this pool */
bool
CrossThreadPool::empty ()
{
return (free_list.write_space() == pending.read_space());
}