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/* $Id: alloccache.c 3141 2018-03-14 21:58:32Z bird $ */
/** @file
* alloccache - Fixed sized allocation cache.
*
* The rational for using an allocation cache, is that it is way faster
* than malloc+free on most systems. It may be more efficient as well,
* depending on the way the heap implementes small allocations. Also,
* with the incdep.c code being threaded, all heaps (except for MSC)
* ran into severe lock contention issues since both the main thread
* and the incdep worker thread was allocating a crazy amount of tiny
* allocations (struct dep, struct nameseq, ++).
*
* Darwin also showed a significant amount of time spent just executing
* free(), which is kind of silly. The alloccache helps a bit here too.
*/
/*
* Copyright (c) 2008-2010 knut st. osmundsen <bird-kBuild-spamx@anduin.net>
*
* This file is part of kBuild.
*
* kBuild 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 3 of the License, or
* (at your option) any later version.
*
* kBuild 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 kBuild. If not, see <http://www.gnu.org/licenses/>
*
*/
/*******************************************************************************
* Header Files *
*******************************************************************************/
#include "makeint.h"
#include "filedef.h"
#include "dep.h"
#include "debug.h"
#include <assert.h>
#ifdef CONFIG_WITH_ALLOC_CACHES
/* Free am item.
This was not inlined because of aliasing issues arrising with GCC.
It is also in a separate file for this reason (it used to be in misc.c
but since free_dep_chain() was using it there, we ran the risk of it
being inlined and gcc screwing up). */
void
alloccache_free (struct alloccache *cache, void *item)
{
#ifndef CONFIG_WITH_ALLOCCACHE_DEBUG
struct alloccache_free_ent *f = (struct alloccache_free_ent *)item;
# if 0 /*ndef NDEBUG*/
struct alloccache_free_ent *c;
unsigned int i = 0;
for (c = cache->free_head; c != NULL; c = c->next, i++)
MY_ASSERT_MSG (c != f && i < 0x10000000,
("i=%u total_count=%u\n", i, cache->total_count));
# endif
f->next = cache->free_head;
cache->free_head = f;
MAKE_STATS(cache->free_count++;);
#else /* CONFIG_WITH_ALLOCCACHE_DEBUG */
struct alloccache **ppcache = (struct alloccache **)item - 1;
MY_ASSERT_MSG (*ppcache == cache, ("*ppcache=%p cache=%p item=%p\n", *ppcache, cache, item));
*ppcache = NULL;
free(ppcache);
#endif /* CONFIG_WITH_ALLOCCACHE_DEBUG */
}
/* Default allocator. */
static void *
alloccache_default_grow_alloc(void *ignore, unsigned int size)
{
return xmalloc (size);
}
/* Worker for growing the cache. */
struct alloccache_free_ent *
alloccache_alloc_grow (struct alloccache *cache)
{
#ifndef CONFIG_WITH_ALLOCCACHE_DEBUG
void *item;
unsigned int items = (64*1024 - 32) / cache->size;
cache->free_start = cache->grow_alloc (cache->grow_arg, items * cache->size);
cache->free_end = cache->free_start + items * cache->size;
cache->total_count+= items;
# ifndef NDEBUG /* skip the first item so the heap can detect free(). */
cache->total_count--;
cache->free_start += cache->size;
# endif
item = cache->free_start;
cache->free_start += cache->size;
/* caller counts */
return (struct alloccache_free_ent *)item;
#else /* CONFIG_WITH_ALLOCCACHE_DEBUG */
/* Prefix the allocation with a cache pointer so alloccahce_free can better
catch incorrect calls. */
struct alloccache **ppcache = (struct alloccache **)xmalloc(sizeof(*ppcache) + cache->size);
*ppcache = cache;
return (struct alloccache_free_ent *)(ppcache + 1);
#endif /* CONFIG_WITH_ALLOCCACHE_DEBUG */
}
/* List of alloc caches, for printing. */
static struct alloccache *alloccache_head = NULL;
/* Initializes an alloc cache */
void
alloccache_init (struct alloccache *cache, unsigned int size, const char *name,
void *(*grow_alloc)(void *grow_arg, unsigned int size), void *grow_arg)
{
unsigned act_size;
/* ensure OK alignment and min sizeof (struct alloccache_free_ent). */
if (size <= sizeof (struct alloccache_free_ent))
act_size = sizeof (struct alloccache_free_ent);
else if (size <= 32)
{
act_size = 4;
while (act_size < size)
act_size <<= 1;
}
else
act_size = (size + 31U) & ~(size_t)31;
/* align the structure. */
cache->free_start = NULL;
cache->free_end = NULL;
cache->free_head = NULL;
cache->size = act_size;
cache->total_count = 0;
cache->alloc_count = 0;
cache->free_count = 0;
cache->name = name;
cache->grow_arg = grow_arg;
cache->grow_alloc = grow_alloc ? grow_alloc : alloccache_default_grow_alloc;
/* link it. */
cache->next = alloccache_head;
alloccache_head = cache;
}
/* Terminate an alloc cache, free all the memory it contains. */
void
alloccache_term (struct alloccache *cache,
void (*term_free)(void *term_arg, void *ptr, unsigned int size), void *term_arg)
{
/*cache->size = 0;*/
(void)cache;
(void)term_free;
(void)term_arg;
/* FIXME: Implement memory segment tracking and cleanup. */
}
/* Joins to caches, unlinking the 2nd one. */
void
alloccache_join (struct alloccache *cache, struct alloccache *eat)
{
assert (cache->size == eat->size);
#if 0 /* probably a waste of time */ /* FIXME: Optimize joining, avoid all list walking. */
/* add the free list... */
if (eat->free_head)
{
unsigned int eat_in_use = eat->alloc_count - eat->free_count;
unsigned int dst_in_use = cache->alloc_count - cache->free_count;
if (!cache->free_head)
cache->free_head = eat->free_head;
else if (eat->total_count - eat_in_use < cache->total_count - dst_ins_use)
{
struct alloccache_free_ent *last = eat->free_head;
while (last->next)
last = last->next;
last->next = cache->free_head;
cache->free_head = eat->free_head;
}
else
{
struct alloccache_free_ent *last = cache->free_head;
while (last->next)
last = last->next;
last->next = eat->free_head;
}
}
/* ... and the free space. */
while (eat->free_start != eat->free_end)
{
struct alloccache_free_ent *f = (struct alloccache_free_ent *)eat->free_start;
eat->free_start += eat->size;
f->next = cache->free_head;
cache->free_head = f;
}
/* and statistics */
cache->alloc_count += eat->alloc_count;
cache->free_count += eat->free_count;
#else
/* and statistics */
cache->alloc_count += eat->alloc_count;
cache->free_count += eat->free_count;
#endif
cache->total_count += eat->total_count;
/* unlink and disable the eat cache */
if (alloccache_head == eat)
alloccache_head = eat->next;
else
{
struct alloccache *cur = alloccache_head;
while (cur->next != eat)
cur = cur->next;
assert (cur && cur->next == eat);
cur->next = eat->next;
}
eat->size = 0;
eat->free_end = eat->free_start = NULL;
eat->free_head = NULL;
}
/* Print one alloc cache. */
void
alloccache_print (struct alloccache *cache)
{
printf (_("\n# Alloc Cache: %s\n"
"# Items: size = %-3u total = %-6u"),
cache->name, cache->size, cache->total_count);
MAKE_STATS(printf (_(" in-use = %-6lu"),
cache->alloc_count - cache->free_count););
MAKE_STATS(printf (_("\n# alloc calls = %-7lu free calls = %-7lu"),
cache->alloc_count, cache->free_count););
printf ("\n");
}
/* Print all alloc caches. */
void
alloccache_print_all (void)
{
struct alloccache *cur;
puts ("");
for (cur = alloccache_head; cur; cur = cur->next)
alloccache_print (cur);
}
#endif /* CONFIG_WITH_ALLOC_CACHES */
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