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elemental-ircd/libratbox/src/balloc.c

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/*
* ircd-ratbox: A slightly useful ircd.
* balloc.c: A block allocator.
*
* Copyright (C) 1990 Jarkko Oikarinen and University of Oulu, Co Center
* Copyright (C) 1996-2002 Hybrid Development Team
* Copyright (C) 2002-2006 ircd-ratbox development team
*
* Below are the orignal headers from the old blalloc.c
*
* File: blalloc.c
* Owner: Wohali (Joan Touzet)
*
* Modified 2001/11/29 for mmap() support by Aaron Sethman <androsyn@ratbox.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
*
*/
/*
* About the block allocator
*
* Basically we have three ways of getting memory off of the operating
* system. Below are this list of methods and the order of preference.
*
* 1. mmap() anonymous pages with the MMAP_ANON flag.
* 2. mmap() via the /dev/zero trick.
* 3. HeapCreate/HeapAlloc (on win32)
* 4. malloc()
*
* The advantages of 1 and 2 are this. We can munmap() the pages which will
* return the pages back to the operating system, thus reducing the size
* of the process as the memory is unused. malloc() on many systems just keeps
* a heap of memory to itself, which never gets given back to the OS, except on
* exit. This of course is bad, if say we have an event that causes us to allocate
* say, 200MB of memory, while our normal memory consumption would be 15MB. In the
* malloc() case, the amount of memory allocated to our process never goes down, as
* malloc() has it locked up in its heap. With the mmap() method, we can munmap()
* the block and return it back to the OS, thus causing our memory consumption to go
* down after we no longer need it.
*
*
*
*/
#include <libratbox_config.h>
#include <ratbox_lib.h>
#ifndef NOBALLOC
#ifdef HAVE_MMAP /* We've got mmap() that is good */
#include <sys/mman.h>
/* HP-UX sucks */
#ifdef MAP_ANONYMOUS
#ifndef MAP_ANON
#define MAP_ANON MAP_ANONYMOUS
#endif
#endif
#endif
#endif
static uintptr_t offset_pad;
/* status information for an allocated block in heap */
struct rb_heap_block {
size_t alloc_size;
rb_dlink_node node;
unsigned long free_count;
void *elems; /* Points to allocated memory */
};
typedef struct rb_heap_block rb_heap_block;
/* information for the root node of the heap */
struct rb_bh {
rb_dlink_node hlist;
size_t elemSize; /* Size of each element to be stored */
unsigned long elemsPerBlock; /* Number of elements per block */
rb_dlink_list block_list;
rb_dlink_list free_list;
char *desc;
};
#ifndef NOBALLOC
static int newblock(rb_bh *bh);
static void rb_bh_gc_event(void *unused);
#endif /* !NOBALLOC */
static rb_dlink_list *heap_lists;
#if defined(WIN32)
static HANDLE block_heap;
#endif
#define rb_bh_fail(x) _rb_bh_fail(x, __FILE__, __LINE__)
static void
_rb_bh_fail(const char *reason, const char *file, int line)
{
rb_lib_log("rb_heap_blockheap failure: %s (%s:%d)", reason, file, line);
abort();
}
#ifndef NOBALLOC
/*
* static inline void free_block(void *ptr, size_t size)
*
* Inputs: The block and its size
* Output: None
* Side Effects: Returns memory for the block back to the OS
*/
static inline void
free_block(void *ptr, size_t size)
{
#ifdef HAVE_MMAP
munmap(ptr, size);
#else
#ifdef _WIN32
HeapFree(block_heap, 0, ptr);
#else
free(ptr);
#endif
#endif
}
#endif /* !NOBALLOC */
/*
* void rb_init_bh(void)
*
* Inputs: None
* Outputs: None
* Side Effects: Initializes the block heap
*/
void
rb_init_bh(void)
{
heap_lists = rb_malloc(sizeof(rb_dlink_list));
offset_pad = sizeof(void *);
/* XXX if you get SIGBUS when trying to use a long long..here is where you need to
* fix your shit
*/
#ifdef __sparc__
if((offset_pad % __alignof__(long long)) != 0) {
offset_pad += __alignof__(long long);
offset_pad &= ~(__alignof__(long long) - 1);
}
#endif
#ifndef NOBALLOC
#ifdef _WIN32
block_heap = HeapCreate(HEAP_NO_SERIALIZE, 0, 0);
#endif
rb_event_addish("rb_bh_gc_event", rb_bh_gc_event, NULL, 300);
#endif /* !NOBALLOC */
}
#ifndef NOBALLOC
/*
* static inline void *get_block(size_t size)
*
* Input: Size of block to allocate
* Output: Pointer to new block
* Side Effects: None
*/
static inline void *
get_block(size_t size)
{
void *ptr;
#ifdef HAVE_MMAP
#ifdef MAP_ANON
ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
#else
int zero_fd;
zero_fd = open("/dev/zero", O_RDWR);
if(zero_fd < 0)
rb_bh_fail("Failed opening /dev/zero");
ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, zero_fd, 0);
close(zero_fd);
#endif /* MAP_ANON */
if(ptr == MAP_FAILED)
ptr = NULL;
#else
#ifdef _WIN32
ptr = HeapAlloc(block_heap, 0, size);
#else
ptr = malloc(size);
#endif
#endif
return (ptr);
}
static void
rb_bh_gc_event(void *unused)
{
rb_dlink_node *ptr;
RB_DLINK_FOREACH(ptr, heap_lists->head) {
rb_bh_gc(ptr->data);
}
}
/* ************************************************************************ */
/* FUNCTION DOCUMENTATION: */
/* newblock */
/* Description: */
/* Allocates a new block for addition to a blockheap */
/* Parameters: */
/* bh (IN): Pointer to parent blockheap. */
/* Returns: */
/* 0 if successful, 1 if not */
/* ************************************************************************ */
static int
newblock(rb_bh *bh)
{
rb_heap_block *b;
unsigned long i;
uintptr_t offset;
rb_dlink_node *node;
/* Setup the initial data structure. */
b = rb_malloc(sizeof(rb_heap_block));
b->alloc_size = bh->elemsPerBlock * bh->elemSize;
b->elems = get_block(b->alloc_size);
if(rb_unlikely(b->elems == NULL)) {
return (1);
}
offset = (uintptr_t)b->elems;
/* Setup our blocks now */
for(i = 0; i < bh->elemsPerBlock; i++, offset += bh->elemSize) {
*((void **)offset) = b;
node = (void *)(offset + offset_pad);
rb_dlinkAdd((void *)offset, node, &bh->free_list);
}
rb_dlinkAdd(b, &b->node, &bh->block_list);
b->free_count = bh->elemsPerBlock;
return (0);
}
#endif /* !NOBALLOC */
/* ************************************************************************ */
/* FUNCTION DOCUMENTATION: */
/* rb_bh_create */
/* Description: */
/* Creates a new blockheap from which smaller blocks can be allocated. */
/* Intended to be used instead of multiple calls to malloc() when */
/* performance is an issue. */
/* Parameters: */
/* elemsize (IN): Size of the basic element to be stored */
/* elemsperblock (IN): Number of elements to be stored in a single block */
/* of memory. When the blockheap runs out of free memory, it will */
/* allocate elemsize * elemsperblock more. */
/* Returns: */
/* Pointer to new rb_bh, or NULL if unsuccessful */
/* ************************************************************************ */
rb_bh *
rb_bh_create(size_t elemsize, int elemsperblock, const char *desc)
{
rb_bh *bh;
lrb_assert(elemsize > 0 && elemsperblock > 0);
lrb_assert(elemsize >= sizeof(rb_dlink_node));
/* Catch idiotic requests up front */
if((elemsize == 0) || (elemsperblock <= 0)) {
rb_bh_fail("Attempting to rb_bh_create idiotic sizes");
}
if(elemsize < sizeof(rb_dlink_node))
rb_bh_fail("Attempt to rb_bh_create smaller than sizeof(rb_dlink_node)");
/* Allocate our new rb_bh */
bh = rb_malloc(sizeof(rb_bh));
#ifndef NOBALLOC
elemsize += offset_pad;
if((elemsize % sizeof(void *)) != 0) {
/* Pad to even pointer boundary */
elemsize += sizeof(void *);
elemsize &= ~(sizeof(void *) - 1);
}
#endif
bh->elemSize = elemsize;
bh->elemsPerBlock = elemsperblock;
if(desc != NULL)
bh->desc = rb_strdup(desc);
#ifndef NOBALLOC
/* Be sure our malloc was successful */
if(newblock(bh)) {
if(bh != NULL)
free(bh);
rb_lib_log("newblock() failed");
rb_outofmemory(); /* die.. out of memory */
}
#endif /* !NOBALLOC */
if(bh == NULL) {
rb_bh_fail("bh == NULL when it shouldn't be");
}
rb_dlinkAdd(bh, &bh->hlist, heap_lists);
return (bh);
}
/* ************************************************************************ */
/* FUNCTION DOCUMENTATION: */
/* rb_bh_alloc */
/* Description: */
/* Returns a pointer to a struct within our rb_bh that's free for */
/* the taking. */
/* Parameters: */
/* bh (IN): Pointer to the Blockheap. */
/* Returns: */
/* Pointer to a structure (void *), or NULL if unsuccessful. */
/* ************************************************************************ */
void *
rb_bh_alloc(rb_bh *bh)
{
#ifndef NOBALLOC
rb_dlink_node *new_node;
rb_heap_block **block;
void *ptr;
#endif
lrb_assert(bh != NULL);
if(rb_unlikely(bh == NULL)) {
rb_bh_fail("Cannot allocate if bh == NULL");
}
#ifdef NOBALLOC
return (rb_malloc(bh->elemSize));
#else
if(bh->free_list.head == NULL) {
/* Allocate new block and assign */
/* newblock returns 1 if unsuccessful, 0 if not */
if(rb_unlikely(newblock(bh))) {
rb_lib_log("newblock() failed");
rb_outofmemory(); /* Well that didn't work either...bail */
}
if(bh->free_list.head == NULL) {
rb_lib_log("out of memory after newblock()...");
rb_outofmemory();
}
}
new_node = bh->free_list.head;
block = (rb_heap_block **) new_node->data;
ptr = (void *)((uintptr_t)new_node->data + (uintptr_t)offset_pad);
rb_dlinkDelete(new_node, &bh->free_list);
(*block)->free_count--;
memset(ptr, 0, bh->elemSize - offset_pad);
return (ptr);
#endif
}
/* ************************************************************************ */
/* FUNCTION DOCUMENTATION: */
/* rb_bh_free */
/* Description: */
/* Returns an element to the free pool, does not free() */
/* Parameters: */
/* bh (IN): Pointer to rb_bh containing element */
/* ptr (in): Pointer to element to be "freed" */
/* Returns: */
/* 0 if successful, 1 if element not contained within rb_bh. */
/* ************************************************************************ */
int
rb_bh_free(rb_bh *bh, void *ptr)
{
#ifndef NOBALLOC
rb_heap_block *block;
void *data;
#endif
lrb_assert(bh != NULL);
lrb_assert(ptr != NULL);
if(rb_unlikely(bh == NULL)) {
rb_lib_log("balloc.c:rb_bhFree() bh == NULL");
return (1);
}
if(rb_unlikely(ptr == NULL)) {
rb_lib_log("balloc.rb_bhFree() ptr == NULL");
return (1);
}
#ifdef NOBALLOC
rb_free(ptr);
#else
data = (void *)((uintptr_t)ptr - (uintptr_t)offset_pad);
block = *(rb_heap_block **) data;
/* XXX */
if(rb_unlikely
(!((uintptr_t)ptr >= (uintptr_t)block->elems
&& (uintptr_t)ptr < (uintptr_t)block->elems + (uintptr_t)block->alloc_size))) {
rb_bh_fail("rb_bh_free() bogus pointer");
}
block->free_count++;
rb_dlinkAdd(data, (rb_dlink_node *)ptr, &bh->free_list);
#endif /* !NOBALLOC */
return (0);
}
/* ************************************************************************ */
/* FUNCTION DOCUMENTATION: */
/* rb_bhDestroy */
/* Description: */
/* Completely free()s a rb_bh. Use for cleanup. */
/* Parameters: */
/* bh (IN): Pointer to the rb_bh to be destroyed. */
/* Returns: */
/* 0 if successful, 1 if bh == NULL */
/* ************************************************************************ */
int
rb_bh_destroy(rb_bh *bh)
{
#ifndef NOBALLOC
rb_dlink_node *ptr, *next;
rb_heap_block *b;
#endif
if(bh == NULL)
return (1);
#ifndef NOBALLOC
RB_DLINK_FOREACH_SAFE(ptr, next, bh->block_list.head) {
b = ptr->data;
free_block(b->elems, b->alloc_size);
rb_free(b);
}
#endif /* !NOBALLOC */
rb_dlinkDelete(&bh->hlist, heap_lists);
rb_free(bh->desc);
rb_free(bh);
return (0);
}
void
rb_bh_usage(rb_bh *bh, size_t *bused, size_t *bfree, size_t *bmemusage, const char **desc)
{
#ifndef NOBALLOC
size_t used, freem, memusage;
if(bh == NULL) {
return;
}
freem = rb_dlink_list_length(&bh->free_list);
used = (rb_dlink_list_length(&bh->block_list) * bh->elemsPerBlock) - freem;
memusage = used * bh->elemSize;
if(bused != NULL)
*bused = used;
if(bfree != NULL)
*bfree = freem;
if(bmemusage != NULL)
*bmemusage = memusage;
if(desc != NULL)
*desc = bh->desc;
#else
if(bused != NULL)
*bused = 0;
if(bfree != NULL)
*bfree = 0;
if(bmemusage != NULL)
*bmemusage = 0;
if(desc != NULL)
*desc = "no blockheap";
#endif
}
void
rb_bh_usage_all(rb_bh_usage_cb *cb, void *data)
{
rb_dlink_node *ptr;
rb_bh *bh;
size_t used, freem, memusage, heapalloc;
static const char *unnamed = "(unnamed_heap)";
const char *desc = unnamed;
if(cb == NULL)
return;
RB_DLINK_FOREACH(ptr, heap_lists->head) {
bh = (rb_bh *)ptr->data;
freem = rb_dlink_list_length(&bh->free_list);
used = (rb_dlink_list_length(&bh->block_list) * bh->elemsPerBlock) - freem;
memusage = used * bh->elemSize;
heapalloc = (freem + used) * bh->elemSize;
if(bh->desc != NULL)
desc = bh->desc;
cb(used, freem, memusage, heapalloc, desc, data);
}
return;
}
void
rb_bh_total_usage(size_t *total_alloc, size_t *total_used)
{
rb_dlink_node *ptr;
size_t total_memory = 0, used_memory = 0, used, freem;
rb_bh *bh;
RB_DLINK_FOREACH(ptr, heap_lists->head) {
bh = (rb_bh *)ptr->data;
freem = rb_dlink_list_length(&bh->free_list);
used = (rb_dlink_list_length(&bh->block_list) * bh->elemsPerBlock) - freem;
used_memory += used * bh->elemSize;
total_memory += (freem + used) * bh->elemSize;
}
if(total_alloc != NULL)
*total_alloc = total_memory;
if(total_used != NULL)
*total_used = used_memory;
}
#ifndef NOBALLOC
int
rb_bh_gc(rb_bh *bh)
{
rb_heap_block *b;
rb_dlink_node *ptr, *next;
unsigned long i;
uintptr_t offset;
if(bh == NULL) {
/* somebody is smoking some craq..(probably lee, but don't tell him that) */
return (1);
}
if((rb_dlink_list_length(&bh->free_list) < bh->elemsPerBlock)
|| rb_dlink_list_length(&bh->block_list) == 1) {
/* There couldn't possibly be an entire free block. Return. */
return (0);
}
RB_DLINK_FOREACH_SAFE(ptr, next, bh->block_list.head) {
b = ptr->data;
if(rb_dlink_list_length(&bh->block_list) == 1)
return (0);
if(b->free_count == bh->elemsPerBlock) {
/* i'm seriously going to hell for this.. */
offset = (uintptr_t)b->elems;
for(i = 0; i < bh->elemsPerBlock; i++, offset += (uintptr_t)bh->elemSize) {
rb_dlinkDelete((rb_dlink_node *)(offset + offset_pad),
&bh->free_list);
}
rb_dlinkDelete(&b->node, &bh->block_list);
free_block(b->elems, b->alloc_size);
rb_free(b);
}
}
return (0);
}
#endif /* !NOBALLOC */
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