vmopen.c   [plain text]

#include	"vmhdr.h"

/*	Opening a new region of allocation.
**	Note that because of possible exotic memory types,
**	all region data must be stored within the space given
**	by the discipline.
**
**	Written by Kiem-Phong Vo, kpv@research.att.com, 01/16/94.
*/

typedef struct _vminit_
{
	Vmdata_t	vd;		/* space for the region itself	*/
	Seg_t		seg;		/* space for segment		*/
	Block_t		block;		/* space for a block		*/
	Head_t		head;		/* space for the fake header	*/
	char		a[3*ALIGN];	/* extra to fuss with alignment	*/
} Vminit_t;

#if __STD_C
Vmalloc_t* vmopen(Vmdisc_t* disc, Vmethod_t* meth, int mode)
#else
Vmalloc_t* vmopen(disc, meth, mode)
Vmdisc_t*	disc;	/* discipline to get segments	*/
Vmethod_t*	meth;	/* method to manage space	*/
int		mode;	/* type of region		*/
#endif
{
	reg Vmalloc_t*	vm;
	reg Vmdata_t*	vd;
	reg size_t	s, a, incr;
	reg Block_t*	b;
	reg Seg_t*	seg;
	Vmuchar_t*	addr;
	reg Vmemory_f	memoryf;
	reg int		e;

	if(!meth || !disc || !(memoryf = disc->memoryf) )
		return NIL(Vmalloc_t*);

	GETPAGESIZE(_Vmpagesize);

	/* note that Vmalloc_t space must be local to process since that's
	   where the meth&disc function addresses are going to be stored */
	if(!(vm = (Vmalloc_t*)vmalloc(Vmheap,sizeof(Vmalloc_t))) )
		return NIL(Vmalloc_t*);
	vm->meth = *meth;
	vm->disc = disc;
	vm->file = NIL(char*);
	vm->line = 0;

	if(disc->exceptf)
	{	addr = NIL(Vmuchar_t*);
		if((e = (*disc->exceptf)(vm,VM_OPEN,(Void_t*)(&addr),disc)) != 0)
		{	if(e < 0 || !addr)
				goto open_error;

			/* align this address */
			if((a = (size_t)(VLONG(addr)%ALIGN)) != 0)
				addr += ALIGN-a;

			/* see if it's a valid region */
			vd = (Vmdata_t*)addr;
			if((vd->mode&meth->meth) != 0)
			{	vm->data = vd;
				return vm;
			}
			else
			{ open_error:
				vmfree(Vmheap,vm);
				return NIL(Vmalloc_t*);
			}
		}
	}

	/* make sure vd->incr is properly rounded */
	incr = disc->round <= 0 ? _Vmpagesize : disc->round;
	incr = MULTIPLE(incr,ALIGN);

	/* get space for region data */
	s = ROUND(sizeof(Vminit_t),incr);
	if(!(addr = (Vmuchar_t*)(*memoryf)(vm,NIL(Void_t*),0,s,disc)) )
	{	vmfree(Vmheap,vm);
		return NIL(Vmalloc_t*);
	}

	/* make sure that addr is aligned */
	if((a = (size_t)(VLONG(addr)%ALIGN)) != 0)
		addr += ALIGN-a;

	/* initialize region */
	vd = (Vmdata_t*)addr;
	vd->mode = (mode&VM_FLAGS) | meth->meth;
	vd->incr = incr;
	vd->pool = 0;
	vd->free = vd->wild = NIL(Block_t*);

	if(vd->mode&(VM_TRACE|VM_MTDEBUG))
		vd->mode &= ~VM_TRUST;

	if(vd->mode&(VM_MTBEST|VM_MTDEBUG|VM_MTPROFILE))
	{	vd->root = NIL(Block_t*);
		for(e = S_TINY-1; e >= 0; --e)
			TINY(vd)[e] = NIL(Block_t*);
		for(e = S_CACHE; e >= 0; --e)
			CACHE(vd)[e] = NIL(Block_t*);
		incr = sizeof(Vmdata_t);
	}
	else	incr = OFFSET(Vmdata_t,root);

	vd->seg = (Seg_t*)(addr + ROUND(incr,ALIGN));
	/**/ ASSERT(VLONG(vd->seg)%ALIGN == 0);

	seg = vd->seg;
	seg->next = NIL(Seg_t*);
	seg->vm = vm;
	seg->addr = (Void_t*)(addr - (a ? ALIGN-a : 0));
	seg->extent = s;
	seg->baddr = addr + s - (a ? ALIGN : 0);
	seg->size = s;	/* this size is larger than usual so that the segment
			   will not be freed until the region is closed. */
	seg->free = NIL(Block_t*);

	/* make a data block out of the remainder */
	b = SEGBLOCK(seg);
	SEG(b) = seg;
	SIZE(b) = seg->baddr - (Vmuchar_t*)b - 2*sizeof(Head_t);
	*SELF(b) = b;
	/**/ ASSERT(SIZE(b)%ALIGN == 0);
	/**/ ASSERT(VLONG(b)%ALIGN == 0);

	/* make a fake header for next block in case of noncontiguous segments */
	SEG(NEXT(b)) = seg;
	SIZE(NEXT(b)) = BUSY|PFREE;

	if(vd->mode&(VM_MTLAST|VM_MTPOOL))
		seg->free = b;
	else	vd->wild = b;

	vm->data = vd;

	/* put into linked list of regions */
	vm->next = Vmheap->next;
	Vmheap->next = vm;

	return vm;
}