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[umalloc] Fail allocations when we run out of external memory

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Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown 2012-03-27 00:18:12 +01:00
parent 0f0a94f2fa
commit 920799a0ba
1 changed files with 22 additions and 7 deletions
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29
src/arch/i386/interface/pcbios/memtop_umalloc.c
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@ -52,6 +52,9 @@ static userptr_t top = UNULL;
/** Bottom of heap (current lowest allocated block) */
static userptr_t bottom = UNULL;
/** Remaining space on heap */
static size_t heap_size;
/**
* Initialise external heap
*
@ -59,12 +62,12 @@ static userptr_t bottom = UNULL;
*/
static int init_eheap ( void ) {
struct memory_map memmap;
unsigned long heap_size = 0;
unsigned int i;
DBG ( "Allocating external heap\n" );
get_memmap ( &memmap );
heap_size = 0;
for ( i = 0 ; i < memmap.count ; i++ ) {
struct memory_region *region = &memmap.regions[i];
unsigned long r_start, r_end;
@ -99,8 +102,8 @@ static int init_eheap ( void ) {
return -ENOMEM;
}
DBG ( "External heap grows downwards from %lx\n",
user_to_phys ( top, 0 ) );
DBG ( "External heap grows downwards from %lx (size %zx)\n",
user_to_phys ( top, 0 ), heap_size );
return 0;
}
@ -110,6 +113,7 @@ static int init_eheap ( void ) {
*/
static void ecollect_free ( void ) {
struct external_memory extmem;
size_t len;
/* Walk the free list and collect empty blocks */
while ( bottom != top ) {
@ -119,8 +123,9 @@ static void ecollect_free ( void ) {
break;
DBG ( "EXTMEM freeing [%lx,%lx)\n", user_to_phys ( bottom, 0 ),
user_to_phys ( bottom, extmem.size ) );
bottom = userptr_add ( bottom,
( extmem.size + sizeof ( extmem ) ) );
len = ( extmem.size + sizeof ( extmem ) );
bottom = userptr_add ( bottom, len );
heap_size += len;
}
}
@ -153,7 +158,12 @@ static userptr_t memtop_urealloc ( userptr_t ptr, size_t new_size ) {
sizeof ( extmem ) );
} else {
/* Create a zero-length block */
if ( heap_size < sizeof ( extmem ) ) {
DBG ( "EXTMEM out of space\n" );
return UNULL;
}
ptr = bottom = userptr_add ( bottom, -sizeof ( extmem ) );
heap_size -= sizeof ( extmem );
DBG ( "EXTMEM allocating [%lx,%lx)\n",
user_to_phys ( ptr, 0 ), user_to_phys ( ptr, 0 ) );
extmem.size = 0;
@ -163,6 +173,10 @@ static userptr_t memtop_urealloc ( userptr_t ptr, size_t new_size ) {
/* Expand/shrink block if possible */
if ( ptr == bottom ) {
/* Update block */
if ( new_size > ( heap_size - extmem.size ) ) {
DBG ( "EXTMEM out of space\n" );
return UNULL;
}
new = userptr_add ( ptr, - ( new_size - extmem.size ) );
align = ( user_to_phys ( new, 0 ) & ( EM_ALIGN - 1 ) );
new_size += align;
@ -174,8 +188,9 @@ static userptr_t memtop_urealloc ( userptr_t ptr, size_t new_size ) {
user_to_phys ( new, new_size ));
memmove_user ( new, 0, ptr, 0, ( ( extmem.size < new_size ) ?
extmem.size : new_size ) );
extmem.size = new_size;
bottom = new;
heap_size -= ( new_size - extmem.size );
extmem.size = new_size;
} else {
/* Cannot expand; can only pretend to shrink */
if ( new_size > extmem.size ) {
@ -193,7 +208,7 @@ static userptr_t memtop_urealloc ( userptr_t ptr, size_t new_size ) {
/* Collect any free blocks and update hidden memory region */
ecollect_free();
hide_umalloc ( user_to_phys ( bottom, -sizeof ( extmem ) ),
hide_umalloc ( user_to_phys ( bottom, 0 ),
user_to_phys ( top, 0 ) );
return ( new_size ? new : UNOWHERE );