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angiosperm/librb/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. 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 <librb_config.h>
#include <rb_lib.h>
static void _rb_bh_fail(const char *reason, const char *file, int line) __attribute__((noreturn));
static uintptr_t offset_pad;
/* 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;
};
static rb_dlink_list *heap_lists;
#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();
}
/*
* 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
}
/* ************************************************************************ */
/* 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));
bh->elemSize = elemsize;
bh->elemsPerBlock = elemsperblock;
if(desc != NULL)
bh->desc = rb_strdup(desc);
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)
{
lrb_assert(bh != NULL);
if(rb_unlikely(bh == NULL))
{
rb_bh_fail("Cannot allocate if bh == NULL");
}
return (rb_malloc(bh->elemSize));
}
/* ************************************************************************ */
/* 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)
{
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);
}
rb_free(ptr);
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)
{
if(bh == NULL)
return (1);
rb_dlinkDelete(&bh->hlist, heap_lists);
rb_free(bh->desc);
rb_free(bh);
return (0);
}
void
rb_bh_usage(rb_bh *bh __attribute__((unused)), size_t *bused, size_t *bfree, size_t *bmemusage, const char **desc)
{
if(bused != NULL)
*bused = 0;
if(bfree != NULL)
*bfree = 0;
if(bmemusage != NULL)
*bmemusage = 0;
if(desc != NULL)
*desc = "no blockheap";
}
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;
}
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