bird/lib/mempool.c

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/*
* BIRD Resource Manager -- Memory Pools
*
* (c) 1998--1999 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#include <stdlib.h>
#include <string.h>
#include "nest/bird.h"
#include "lib/resource.h"
struct lp_chunk {
struct lp_chunk *next;
byte data[0];
};
struct linpool {
resource r;
byte *ptr, *end;
struct lp_chunk *first, *current, **plast; /* Normal (reusable) chunks */
struct lp_chunk *first_large; /* Large chunks */
unsigned chunk_size, threshold, total, total_large;
};
void lp_free(resource *);
void lp_dump(resource *);
static struct resclass lp_class = {
"LinPool",
sizeof(struct linpool),
lp_free,
lp_dump
};
linpool
*lp_new(pool *p, unsigned blk)
{
linpool *m = ralloc(p, &lp_class);
m->ptr = m->end = NULL;
m->first = m->current = NULL;
m->plast = &m->first;
m->first_large = NULL;
m->chunk_size = blk;
m->threshold = 3*blk/4;
m->total = m->total_large = 0;
return m;
}
void *
lp_alloc(linpool *m, unsigned size)
{
byte *a = (byte *) ALIGN((unsigned long) m->ptr, CPU_STRUCT_ALIGN);
byte *e = a + size;
if (e <= m->end)
{
m->ptr = e;
return a;
}
else
{
struct lp_chunk *c;
if (size >= m->threshold)
{
/* Too large => allocate large chunk */
c = xmalloc(sizeof(struct lp_chunk) + size);
m->total_large += size;
c->next = m->first_large;
m->first_large = c->next;
}
else
{
if (m->current && m->current->next)
/* Still have free chunks from previous incarnation (before lp_flush()) */
c = m->current->next;
else
{
/* Need to allocate a new chunk */
c = xmalloc(sizeof(struct lp_chunk) + m->chunk_size);
m->total += m->chunk_size;
*m->plast = c;
m->plast = &c->next;
c->next = NULL;
}
m->current = c;
m->ptr = c->data + size;
m->end = c->data + m->chunk_size;
}
return c->data;
}
}
void *
lp_allocu(linpool *m, unsigned size)
{
byte *a = m->ptr;
byte *e = a + size;
if (e <= m->end)
{
m->ptr = e;
return a;
}
return lp_alloc(m, size);
}
void *
lp_allocz(linpool *m, unsigned size)
{
void *z = lp_alloc(m, size);
bzero(z, size);
return z;
}
void
lp_flush(linpool *m)
{
struct lp_chunk *c;
/* Relink all normal chunks to free list and free all large chunks */
m->ptr = m->end = NULL;
m->current = m->first;
while (c = m->first_large)
{
m->first_large = c->next;
xfree(c);
}
m->total_large = 0;
}
void
lp_free(resource *r)
{
linpool *m = (linpool *) r;
struct lp_chunk *c, *d;
for(d=m->first; d; d = c)
{
c = d->next;
xfree(d);
}
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for(d=m->first_large; d; d = c)
{
c = d->next;
xfree(d);
}
}
void
lp_dump(resource *r)
{
linpool *m = (linpool *) r;
struct lp_chunk *c;
int cnt, cntl;
for(cnt=0, c=m->first; c; c=c->next, cnt++)
;
for(cntl=0, c=m->first_large; c; c=c->next, cntl++)
;
debug("(chunk=%d threshold=%d count=%d+%d total=%d+%d)\n",
m->chunk_size,
m->threshold,
cnt,
cntl,
m->total,
m->total_large);
}