source: trunk/third/sendmail/libsm/rpool.c @ 19204

/*
 * Copyright (c) 2000-2002 Sendmail, Inc. and its suppliers.
 *      All rights reserved.
 *
 * By using this file, you agree to the terms and conditions set
 * forth in the LICENSE file which can be found at the top level of
 * the sendmail distribution.
 */

#include <sm/gen.h>
SM_RCSID("@(#)$Id: rpool.c,v 1.1.1.1 2003-04-08 15:06:48 zacheiss Exp $")

/*
**  resource pools
**  For documentation, see rpool.html
*/

#include <sm/exc.h>
#include <sm/heap.h>
#include <sm/rpool.h>
#include <sm/varargs.h>
#include <sm/conf.h>
#if _FFR_PERF_RPOOL
# include <syslog.h>
#endif /* _FFR_PERF_RPOOL */

const char SmRpoolMagic[] = "sm_rpool";

typedef union
{
        SM_POOLLINK_T   link;
        char            align[SM_ALIGN_SIZE];
} SM_POOLHDR_T;

/*
**  Tune this later
*/

#define POOLSIZE                4096
#define BIG_OBJECT_RATIO        10

/*
**  SM_RPOOL_ALLOCBLOCK_X -- allocate a new block for an rpool.
**
**      Parameters:
**              rpool -- rpool to which the block should be added.
**              size -- size of block.
**
**      Returns:
**              Pointer to block.
**
**      Exceptions:
**              F:sm_heap -- out of memory
*/

static char *
sm_rpool_allocblock_x(rpool, size)
        SM_RPOOL_T *rpool;
        size_t size;
{
        SM_POOLLINK_T *p;

        p = sm_malloc_x(sizeof(SM_POOLHDR_T) + size);
        p->sm_pnext = rpool->sm_pools;
        rpool->sm_pools = p;
        return (char*) p + sizeof(SM_POOLHDR_T);
}

/*
**  SM_RPOOL_ALLOCBLOCK -- allocate a new block for an rpool.
**
**      Parameters:
**              rpool -- rpool to which the block should be added.
**              size -- size of block.
**
**      Returns:
**              Pointer to block, NULL on failure.
*/

static char *
sm_rpool_allocblock(rpool, size)
        SM_RPOOL_T *rpool;
        size_t size;
{
        SM_POOLLINK_T *p;

        p = sm_malloc(sizeof(SM_POOLHDR_T) + size);
        if (p == NULL)
                return NULL;
        p->sm_pnext = rpool->sm_pools;
        rpool->sm_pools = p;
        return (char*) p + sizeof(SM_POOLHDR_T);
}

/*
**  SM_RPOOL_MALLOC_TAGGED_X -- allocate memory from rpool
**
**      Parameters:
**              rpool -- rpool from which memory should be allocated;
**                      can be NULL, use sm_malloc() then.
**              size -- size of block.
**              file -- filename.
**              line -- line number in file.
**              group -- heap group for debugging.
**
**      Returns:
**              Pointer to block.
**
**      Exceptions:
**              F:sm_heap -- out of memory
**
**      Notice: XXX
**              if size == 0 and the rpool is new (no memory
**              allocated yet) NULL is returned!
**              We could solve this by
**              - wasting 1 byte (size < avail)
**              - checking for rpool->sm_poolptr != NULL
**              - not asking for 0 sized buffer
*/

void *
#if SM_HEAP_CHECK
sm_rpool_malloc_tagged_x(rpool, size, file, line, group)
        SM_RPOOL_T *rpool;
        size_t size;
        char *file;
        int line;
        int group;
#else /* SM_HEAP_CHECK */
sm_rpool_malloc_x(rpool, size)
        SM_RPOOL_T *rpool;
        size_t size;
#endif /* SM_HEAP_CHECK */
{
        char *ptr;

        if (rpool == NULL)
                return sm_malloc_tagged_x(size, file, line, group);

        /* Ensure that size is properly aligned. */
        if (size & SM_ALIGN_BITS)
                size = (size & ~SM_ALIGN_BITS) + SM_ALIGN_SIZE;

        /* The common case.  This is optimized for speed. */
        if (size <= rpool->sm_poolavail)
        {
                ptr = rpool->sm_poolptr;
                rpool->sm_poolptr += size;
                rpool->sm_poolavail -= size;
                return ptr;
        }

        /*
        **  The slow case: we need to call malloc.
        **  The SM_REQUIRE assertion is deferred until now, for speed.
        **  That's okay: we set rpool->sm_poolavail to 0 when we free an rpool,
        **  so the common case code won't be triggered on a dangling pointer.
        */

        SM_REQUIRE(rpool->sm_magic == SmRpoolMagic);

        /*
        **  If size > sm_poolsize, then malloc a new block especially for
        **  this request.  Future requests will be allocated from the
        **  current pool.
        **
        **  What if the current pool is mostly unallocated, and the current
        **  request is larger than the available space, but < sm_poolsize?
        **  If we discard the current pool, and start allocating from a new
        **  pool, then we will be wasting a lot of space.  For this reason,
        **  we malloc a block just for the current request if size >
        **  sm_bigobjectsize, where sm_bigobjectsize <= sm_poolsize.
        **  Thus, the most space that we will waste at the end of a pool
        **  is sm_bigobjectsize - 1.
        */

        if (size > rpool->sm_bigobjectsize)
        {
#if _FFR_PERF_RPOOL
                ++rpool->sm_nbigblocks;
#endif /* _FFR_PERF_RPOOL */
                return sm_rpool_allocblock_x(rpool, size);
        }
        SM_ASSERT(rpool->sm_bigobjectsize <= rpool->sm_poolsize);
        ptr = sm_rpool_allocblock_x(rpool, rpool->sm_poolsize);
        rpool->sm_poolptr = ptr + size;
        rpool->sm_poolavail = rpool->sm_poolsize - size;
#if _FFR_PERF_RPOOL
        ++rpool->sm_npools;
#endif /* _FFR_PERF_RPOOL */
        return ptr;
}

/*
**  SM_RPOOL_MALLOC_TAGGED -- allocate memory from rpool
**
**      Parameters:
**              rpool -- rpool from which memory should be allocated;
**                      can be NULL, use sm_malloc() then.
**              size -- size of block.
**              file -- filename.
**              line -- line number in file.
**              group -- heap group for debugging.
**
**      Returns:
**              Pointer to block, NULL on failure.
**
**      Notice: XXX
**              if size == 0 and the rpool is new (no memory
**              allocated yet) NULL is returned!
**              We could solve this by
**              - wasting 1 byte (size < avail)
**              - checking for rpool->sm_poolptr != NULL
**              - not asking for 0 sized buffer
*/

void *
#if SM_HEAP_CHECK
sm_rpool_malloc_tagged(rpool, size, file, line, group)
        SM_RPOOL_T *rpool;
        size_t size;
        char *file;
        int line;
        int group;
#else /* SM_HEAP_CHECK */
sm_rpool_malloc(rpool, size)
        SM_RPOOL_T *rpool;
        size_t size;
#endif /* SM_HEAP_CHECK */
{
        char *ptr;

        if (rpool == NULL)
                return sm_malloc_tagged(size, file, line, group);

        /* Ensure that size is properly aligned. */
        if (size & SM_ALIGN_BITS)
                size = (size & ~SM_ALIGN_BITS) + SM_ALIGN_SIZE;

        /* The common case.  This is optimized for speed. */
        if (size <= rpool->sm_poolavail)
        {
                ptr = rpool->sm_poolptr;
                rpool->sm_poolptr += size;
                rpool->sm_poolavail -= size;
                return ptr;
        }

        /*
        **  The slow case: we need to call malloc.
        **  The SM_REQUIRE assertion is deferred until now, for speed.
        **  That's okay: we set rpool->sm_poolavail to 0 when we free an rpool,
        **  so the common case code won't be triggered on a dangling pointer.
        */

        SM_REQUIRE(rpool->sm_magic == SmRpoolMagic);

        /*
        **  If size > sm_poolsize, then malloc a new block especially for
        **  this request.  Future requests will be allocated from the
        **  current pool.
        **
        **  What if the current pool is mostly unallocated, and the current
        **  request is larger than the available space, but < sm_poolsize?
        **  If we discard the current pool, and start allocating from a new
        **  pool, then we will be wasting a lot of space.  For this reason,
        **  we malloc a block just for the current request if size >
        **  sm_bigobjectsize, where sm_bigobjectsize <= sm_poolsize.
        **  Thus, the most space that we will waste at the end of a pool
        **  is sm_bigobjectsize - 1.
        */

        if (size > rpool->sm_bigobjectsize)
        {
#if _FFR_PERF_RPOOL
                ++rpool->sm_nbigblocks;
#endif /* _FFR_PERF_RPOOL */
                return sm_rpool_allocblock(rpool, size);
        }
        SM_ASSERT(rpool->sm_bigobjectsize <= rpool->sm_poolsize);
        ptr = sm_rpool_allocblock(rpool, rpool->sm_poolsize);
        if (ptr == NULL)
                return NULL;
        rpool->sm_poolptr = ptr + size;
        rpool->sm_poolavail = rpool->sm_poolsize - size;
#if _FFR_PERF_RPOOL
        ++rpool->sm_npools;
#endif /* _FFR_PERF_RPOOL */
        return ptr;
}

/*
**  SM_RPOOL_NEW_X -- create a new rpool.
**
**      Parameters:
**              parent -- pointer to parent rpool, can be NULL.
**
**      Returns:
**              Pointer to new rpool.
*/

SM_RPOOL_T *
sm_rpool_new_x(parent)
        SM_RPOOL_T *parent;
{
        SM_RPOOL_T *rpool;

        rpool = sm_malloc_x(sizeof(SM_RPOOL_T));
        if (parent == NULL)
                rpool->sm_parentlink = NULL;
        else
        {
                SM_TRY
                        rpool->sm_parentlink = sm_rpool_attach_x(parent,
                                        (SM_RPOOL_RFREE_T) sm_rpool_free,
                                        (void *) rpool);
                SM_EXCEPT(exc, "*")
                        sm_free(rpool);
                        sm_exc_raise_x(exc);
                SM_END_TRY
        }
        rpool->sm_magic = SmRpoolMagic;

        rpool->sm_poolsize = POOLSIZE - sizeof(SM_POOLHDR_T);
        rpool->sm_bigobjectsize = rpool->sm_poolsize / BIG_OBJECT_RATIO;
        rpool->sm_poolptr = NULL;
        rpool->sm_poolavail = 0;
        rpool->sm_pools = NULL;

        rpool->sm_rptr = NULL;
        rpool->sm_ravail = 0;
        rpool->sm_rlists = NULL;
#if _FFR_PERF_RPOOL
        rpool->sm_nbigblocks = 0;
        rpool->sm_npools = 0;
#endif /* _FFR_PERF_RPOOL */

        return rpool;
}

/*
**  SM_RPOOL_SETSIZES -- set sizes for rpool.
**
**      Parameters:
**              poolsize -- size of a single rpool block.
**              bigobjectsize -- if this size is exceeded, an individual
**                      block is allocated (must be less or equal poolsize).
**
**      Returns:
**              none.
*/

void
sm_rpool_setsizes(rpool, poolsize, bigobjectsize)
        SM_RPOOL_T *rpool;
        size_t poolsize;
        size_t bigobjectsize;
{
        SM_REQUIRE(poolsize >= bigobjectsize);
        if (poolsize == 0)
                poolsize = POOLSIZE - sizeof(SM_POOLHDR_T);
        if (bigobjectsize == 0)
                bigobjectsize = poolsize / BIG_OBJECT_RATIO;
        rpool->sm_poolsize = poolsize;
        rpool->sm_bigobjectsize = bigobjectsize;
}

/*
**  SM_RPOOL_FREE -- free an rpool and release all of its resources.
**
**      Parameters:
**              rpool -- rpool to free.
**
**      Returns:
**              none.
*/

void
sm_rpool_free(rpool)
        SM_RPOOL_T *rpool;
{
        SM_RLIST_T *rl, *rnext;
        SM_RESOURCE_T *r, *rmax;
        SM_POOLLINK_T *pp, *pnext;

        if (rpool == NULL)
                return;

        /*
        **  It's important to free the resources before the memory pools,
        **  because the resource free functions might modify the contents
        **  of the memory pools.
        */

        rl = rpool->sm_rlists;
        if (rl != NULL)
        {
                rmax = rpool->sm_rptr;
                for (;;)
                {
                        for (r = rl->sm_rvec; r < rmax; ++r)
                        {
                                if (r->sm_rfree != NULL)
                                        r->sm_rfree(r->sm_rcontext);
                        }
                        rnext = rl->sm_rnext;
                        sm_free(rl);
                        if (rnext == NULL)
                                break;
                        rl = rnext;
                        rmax = &rl->sm_rvec[SM_RLIST_MAX];
                }
        }

        /*
        **  Now free the memory pools.
        */

        for (pp = rpool->sm_pools; pp != NULL; pp = pnext)
        {
                pnext = pp->sm_pnext;
                sm_free(pp);
        }

        /*
        **  Disconnect rpool from its parent.
        */

        if (rpool->sm_parentlink != NULL)
                *rpool->sm_parentlink = NULL;

        /*
        **  Setting these fields to zero means that any future to attempt
        **  to use the rpool after it is freed will cause an assertion failure.
        */

        rpool->sm_magic = NULL;
        rpool->sm_poolavail = 0;
        rpool->sm_ravail = 0;

#if _FFR_PERF_RPOOL
        if (rpool->sm_nbigblocks > 0 || rpool->sm_npools > 1)
                syslog(LOG_NOTICE,
                        "perf: rpool=%lx, sm_nbigblocks=%d, sm_npools=%d",
                        (long) rpool, rpool->sm_nbigblocks, rpool->sm_npools);
        rpool->sm_nbigblocks = 0;
        rpool->sm_npools = 0;
#endif /* _FFR_PERF_RPOOL */
        sm_free(rpool);
}

/*
**  SM_RPOOL_ATTACH_X -- attach a resource to an rpool.
**
**      Parameters:
**              rpool -- rpool to which resource should be attached.
**              rfree -- function to call when rpool is freed.
**              rcontext -- argument for function to call when rpool is freed.
**
**      Returns:
**              Pointer to allocated function.
**
**      Exceptions:
**              F:sm_heap -- out of memory
*/

SM_RPOOL_ATTACH_T
sm_rpool_attach_x(rpool, rfree, rcontext)
        SM_RPOOL_T *rpool;
        SM_RPOOL_RFREE_T rfree;
        void *rcontext;
{
        SM_RLIST_T *rl;
        SM_RPOOL_ATTACH_T a;

        SM_REQUIRE_ISA(rpool, SmRpoolMagic);

        if (rpool->sm_ravail == 0)
        {
                rl = sm_malloc_x(sizeof(SM_RLIST_T));
                rl->sm_rnext = rpool->sm_rlists;
                rpool->sm_rlists = rl;
                rpool->sm_rptr = rl->sm_rvec;
                rpool->sm_ravail = SM_RLIST_MAX;
        }

        a = &rpool->sm_rptr->sm_rfree;
        rpool->sm_rptr->sm_rfree = rfree;
        rpool->sm_rptr->sm_rcontext = rcontext;
        ++rpool->sm_rptr;
        --rpool->sm_ravail;
        return a;
}