unsigned VMShrink()
{
int i;
int j;
unsigned kill_time;
unsigned kill_i;
unsigned kill_j;
virt_page *pg;
imp_image_handle *ii;
kill_time = UINT_MAX;
kill_i = 0;
kill_j = 0;
for( ii = ImageList; ii != NULL; ii = ii->next_image ) {
if( ii->virt != NULL ) {
for( i = ii->vm_dir_num-1; i >= 0; --i ) {
if( ii->virt[i] != NULL ) {
for( j = DIR_SIZE-1; j >= 0; --j ) {
pg = ii->virt[i][j];
if( pg != NULL && pg->offset == 0 ) {
if( kill_time > pg->block->time_stamp ) {
kill_time = pg->block->time_stamp;
kill_i = i;
kill_j = j;
}
}
}
}
}
}
}
if( kill_time == UINT_MAX ) return( 0 );
return( KillPages( ii, kill_i, kill_j ) );
}
unsigned VMShrink( void )
{
int i;
int j;
unsigned kill_time;
unsigned kill_i;
unsigned kill_j;
virt_page *pg;
imp_image_handle *iih;
imp_image_handle *kill_iih;
kill_time = UINT_MAX;
kill_i = 0;
kill_j = 0;
kill_iih = NULL;
/* search oldest page by time_stamp */
for( iih = ImageList; iih != NULL; iih = iih->next_image ) {
if( iih->virt != NULL ) {
for( i = iih->vm_dir_num-1; i >= 0; --i ) {
if( iih->virt[i] != NULL ) {
for( j = DIR_SIZE-1; j >= 0; --j ) {
pg = iih->virt[i][j];
if( pg != NULL && pg->offset == 0 ) {
if( kill_time > pg->block->time_stamp ) {
kill_time = pg->block->time_stamp;
kill_i = i;
kill_j = j;
kill_iih = iih;
}
}
}
}
}
}
}
if( kill_iih == NULL )
return( 0 );
return( KillPages( kill_iih, kill_i, kill_j ) );
}
void *VMBlock( imp_image_handle *iih, virt_mem start, size_t len )
{
unsigned dir_idx;
unsigned pg_idx;
unsigned tmp_idx;
unsigned i;
unsigned j;
unsigned num_pages;
virt_mem pg_start;
virt_page *pg;
virt_page *zero;
loaded_block *block;
dir_idx = GET_DIR( start );
if( iih->virt[dir_idx] == NULL ) {
if( !InitPageDir( iih, dir_idx ) ) {
return( NULL );
}
}
pg_idx = GET_PAGE( start );
len += start % VM_PAGE_SIZE;
pg_start = start & ~(virt_mem)(VM_PAGE_SIZE - 1);
pg = iih->virt[dir_idx][pg_idx];
if( pg == NULL || ( pg->block->len - pg->offset ) < len ) {
/* unloaded previously loaded block */
if( pg != NULL ) {
tmp_idx = dir_idx;
/* find first page of the block */
i = pg_idx;
for( ;; ) {
iih->virt[tmp_idx][i] = NULL;
if( pg->offset == 0 )
break;
if( i == 0 ) {
--tmp_idx;
i = DIR_SIZE;
}
--i;
--pg;
}
DCFree( pg );
}
num_pages = BLOCK_FACTOR( len, VM_PAGE_SIZE );
pg = DCAlloc( num_pages * ( sizeof( *pg ) + VM_PAGE_SIZE ) + sizeof( loaded_block ) - 1 );
if( pg == NULL ) {
DCStatus( DS_ERR | DS_NO_MEM );
return( NULL );
}
/* set up new page table entries */
block = (loaded_block *)&pg[num_pages];
tmp_idx = dir_idx;
for( j = pg_idx, i = 0; i < num_pages; ++j, ++i ) {
pg[i].block = block;
pg[i].offset = i * VM_PAGE_SIZE;
if( j >= DIR_SIZE ) {
++tmp_idx;
j = 0;
}
if( iih->virt[tmp_idx] == NULL ) {
if( !InitPageDir( iih, tmp_idx ) ) {
/* unwind the setup already done */
num_pages = i;
for( i = 0; i < num_pages; ++i, ++pg_idx ) {
if( pg_idx >= DIR_SIZE ) {
++dir_idx;
pg_idx = 0;
}
iih->virt[dir_idx][pg_idx] = NULL;
}
DCFree( pg );
return( NULL );
}
}
if( iih->virt[tmp_idx][j] != NULL ) {
/*
We just ran into another allocated block, so we have
to kill all the pages mapped in by it. We know that
if the page pointer is non-NULL, it will be offset==0
since KillPages will clean out the others.
*/
KillPages( iih, tmp_idx, j );
}
iih->virt[tmp_idx][j] = &pg[i];
}
/* read in new block */
len = num_pages * VM_PAGE_SIZE;
block->len = len;
pg_start += iih->bias;
if( DCSeek( iih->sym_fp, pg_start, DIG_ORG ) ) {
DCStatus( DS_ERR | DS_FSEEK_FAILED );
return( NULL );
}
/* last block might be a short read */
if( DCRead( iih->sym_fp, pg->block->data, len ) == DIG_RW_ERROR ) {
DCStatus( DS_ERR | DS_FREAD_FAILED );
return( NULL );
}
pg = iih->virt[dir_idx][pg_idx];
}
++TimeStamp;
if( TimeStamp == 0 ) {
/* deal with wrap-around */
for( iih = ImageList; iih != NULL; iih = iih->next_image ) {
if( iih->virt != NULL ) {
for( i = iih->vm_dir_num; i-- > 0; ) {
if( iih->virt[i] != NULL ) {
for( j = DIR_SIZE; j-- > 0; ) {
zero = iih->virt[i][j];
if( zero != NULL ) {
zero->block->time_stamp = 0;
}
}
}
}
}
}
++TimeStamp;
}
pg->block->time_stamp = TimeStamp;
return( &pg->block->data[(start & (VM_PAGE_SIZE - 1)) + pg->offset] );
}
