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minix/servers/vm/alloc.c

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/* This file is concerned with allocating and freeing arbitrary-size blocks of
* physical memory on behalf of the FORK and EXEC system calls. The key data
* structure used is the hole table, which maintains a list of holes in memory.
* It is kept sorted in order of increasing memory address. The addresses
* it contains refers to physical memory, starting at absolute address 0
* (i.e., they are not relative to the start of PM). During system
* initialization, that part of memory containing the interrupt vectors,
* kernel, and PM are "allocated" to mark them as not available and to
* remove them from the hole list.
*
* The entry points into this file are:
* alloc_mem: allocate a given sized chunk of memory
* free_mem: release a previously allocated chunk of memory
* mem_init: initialize the tables when PM start up
*/
#define _SYSTEM 1
#include <minix/com.h>
#include <minix/callnr.h>
#include <minix/type.h>
#include <minix/config.h>
#include <minix/const.h>
#include <minix/sysutil.h>
#include <minix/syslib.h>
#include <minix/debug.h>
#include <minix/bitmap.h>
#include <sys/mman.h>
#include <limits.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <memory.h>
#include "vm.h"
#include "proto.h"
#include "util.h"
#include "glo.h"
#include "pagerange.h"
#include "addravl.h"
#include "sanitycheck.h"
#include "memlist.h"
/* AVL tree of free pages. */
addr_avl addravl;
/* Used for sanity check. */
PRIVATE phys_bytes mem_low, mem_high;
#define assert_range(addr, len) \
assert((addr) >= mem_low); \
assert((addr) + (len) - 1 <= mem_high);
struct hole {
struct hole *h_next; /* pointer to next entry on the list */
phys_clicks h_base; /* where does the hole begin? */
phys_clicks h_len; /* how big is the hole? */
int freelist;
int holelist;
};
static int startpages;
#define NIL_HOLE (struct hole *) 0
#define _NR_HOLES (_NR_PROCS*2) /* No. of memory holes maintained by VM */
PRIVATE struct hole hole[_NR_HOLES];
PRIVATE struct hole *hole_head; /* pointer to first hole */
PRIVATE struct hole *free_slots;/* ptr to list of unused table slots */
FORWARD _PROTOTYPE( void del_slot, (struct hole *prev_ptr, struct hole *hp) );
FORWARD _PROTOTYPE( void merge, (struct hole *hp) );
FORWARD _PROTOTYPE( void free_pages, (phys_bytes addr, int pages) );
FORWARD _PROTOTYPE( phys_bytes alloc_pages, (int pages, int flags,
phys_bytes *ret));
#if SANITYCHECKS
FORWARD _PROTOTYPE( void holes_sanity_f, (char *fn, int line) );
#define CHECKHOLES holes_sanity_f(__FILE__, __LINE__)
#define PAGESPERGB (1024*1024*1024/VM_PAGE_SIZE) /* 1GB of memory */
#define MAXPAGES (2*PAGESPERGB)
#define CHUNKS BITMAP_CHUNKS(MAXPAGES)
PRIVATE bitchunk_t pagemap[CHUNKS];
#else
#define CHECKHOLES
#endif
#if SANITYCHECKS
/*===========================================================================*
* holes_sanity_f *
*===========================================================================*/
PRIVATE void holes_sanity_f(file, line)
char *file;
int line;
{
#define myassert(c) { \
if(!(c)) { \
printf("holes_sanity_f:%s:%d: %s failed\n", file, line, #c); \
util_stacktrace(); \
panic("assert failed"); } \
}
int h, c = 0, n = 0;
struct hole *hp;
/* Reset flags */
for(h = 0; h < _NR_HOLES; h++) {
hole[h].freelist = 0;
hole[h].holelist = 0;
}
/* Mark all holes on freelist. */
for(hp = free_slots; hp; hp = hp->h_next) {
myassert(!hp->freelist);
myassert(!hp->holelist);
hp->freelist = 1;
myassert(c < _NR_HOLES);
c++;
n++;
}
/* Mark all holes on holelist. */
c = 0;
for(hp = hole_head; hp; hp = hp->h_next) {
myassert(!hp->freelist);
myassert(!hp->holelist);
hp->holelist = 1;
myassert(c < _NR_HOLES);
c++;
n++;
}
/* Check there are exactly the right number of nodes. */
myassert(n == _NR_HOLES);
/* Make sure each slot is on exactly one of the list. */
c = 0;
for(h = 0; h < _NR_HOLES; h++) {
hp = &hole[h];
myassert(hp->holelist || hp->freelist);
myassert(!(hp->holelist && hp->freelist));
myassert(c < _NR_HOLES);
c++;
}
/* Make sure no holes overlap. */
for(hp = hole_head; hp && hp->h_next; hp = hp->h_next) {
myassert(hp->holelist);
hp->holelist = 1;
/* No holes overlap. */
myassert(hp->h_base + hp->h_len <= hp->h_next->h_base);
/* No uncoalesced holes. */
myassert(hp->h_base + hp->h_len < hp->h_next->h_base);
}
}
#endif
/*===========================================================================*
* alloc_mem *
*===========================================================================*/
PUBLIC phys_clicks alloc_mem(phys_clicks clicks, u32_t memflags)
{
/* Allocate a block of memory from the free list using first fit. The block
* consists of a sequence of contiguous bytes, whose length in clicks is
* given by 'clicks'. A pointer to the block is returned. The block is
* always on a click boundary. This procedure is called when memory is
* needed for FORK or EXEC.
*/
register struct hole *hp, *prev_ptr;
phys_clicks old_base, mem = NO_MEM, align_clicks = 0;
int s;
if(memflags & PAF_ALIGN64K) {
align_clicks = (64 * 1024) / CLICK_SIZE;
clicks += align_clicks;
}
if(vm_paged) {
assert(CLICK_SIZE == VM_PAGE_SIZE);
mem = alloc_pages(clicks, memflags, NULL);
} else {
CHECKHOLES;
prev_ptr = NIL_HOLE;
hp = hole_head;
while (hp != NIL_HOLE) {
if (hp->h_len >= clicks) {
/* We found a hole that is big enough. Use it. */
old_base = hp->h_base; /* remember where it started */
hp->h_base += clicks; /* bite a piece off */
hp->h_len -= clicks; /* ditto */
/* Delete the hole if used up completely. */
if (hp->h_len == 0) del_slot(prev_ptr, hp);
/* Anything special needs to happen? */
if(memflags & PAF_CLEAR) {
if ((s= sys_memset(0, CLICK_SIZE*old_base,
CLICK_SIZE*clicks)) != OK) {
panic("alloc_mem: sys_memset failed: %d", s);
}
}
/* Return the start address of the acquired block. */
CHECKHOLES;
mem = old_base;
break;
}
prev_ptr = hp;
hp = hp->h_next;
}
}
if(mem == NO_MEM)
return mem;
CHECKHOLES;
if(align_clicks) {
phys_clicks o;
o = mem % align_clicks;
if(o > 0) {
phys_clicks e;
e = align_clicks - o;
free_mem(mem, e);
mem += e;
}
}
CHECKHOLES;
return mem;
}
/*===========================================================================*
* free_mem *
*===========================================================================*/
PUBLIC void free_mem(phys_clicks base, phys_clicks clicks)
{
/* Return a block of free memory to the hole list. The parameters tell where
* the block starts in physical memory and how big it is. The block is added
* to the hole list. If it is contiguous with an existing hole on either end,
* it is merged with the hole or holes.
*/
register struct hole *hp, *new_ptr, *prev_ptr;
CHECKHOLES;
if (clicks == 0) return;
if(vm_paged) {
assert(CLICK_SIZE == VM_PAGE_SIZE);
free_pages(base, clicks);
return;
}
if ( (new_ptr = free_slots) == NIL_HOLE)
panic("hole table full");
new_ptr->h_base = base;
new_ptr->h_len = clicks;
free_slots = new_ptr->h_next;
hp = hole_head;
/* If this block's address is numerically less than the lowest hole currently
* available, or if no holes are currently available, put this hole on the
* front of the hole list.
*/
if (hp == NIL_HOLE || base <= hp->h_base) {
/* Block to be freed goes on front of the hole list. */
new_ptr->h_next = hp;
hole_head = new_ptr;
merge(new_ptr);
CHECKHOLES;
return;
}
/* Block to be returned does not go on front of hole list. */
prev_ptr = NIL_HOLE;
while (hp != NIL_HOLE && base > hp->h_base) {
prev_ptr = hp;
hp = hp->h_next;
}
/* We found where it goes. Insert block after 'prev_ptr'. */
new_ptr->h_next = prev_ptr->h_next;
prev_ptr->h_next = new_ptr;
merge(prev_ptr); /* sequence is 'prev_ptr', 'new_ptr', 'hp' */
CHECKHOLES;
}
/*===========================================================================*
* del_slot *
*===========================================================================*/
PRIVATE void del_slot(prev_ptr, hp)
/* pointer to hole entry just ahead of 'hp' */
register struct hole *prev_ptr;
/* pointer to hole entry to be removed */
register struct hole *hp;
{
/* Remove an entry from the hole list. This procedure is called when a
* request to allocate memory removes a hole in its entirety, thus reducing
* the numbers of holes in memory, and requiring the elimination of one
* entry in the hole list.
*/
if (hp == hole_head)
hole_head = hp->h_next;
else
prev_ptr->h_next = hp->h_next;
hp->h_next = free_slots;
hp->h_base = hp->h_len = 0;
free_slots = hp;
}
/*===========================================================================*
* merge *
*===========================================================================*/
PRIVATE void merge(hp)
register struct hole *hp; /* ptr to hole to merge with its successors */
{
/* Check for contiguous holes and merge any found. Contiguous holes can occur
* when a block of memory is freed, and it happens to abut another hole on
* either or both ends. The pointer 'hp' points to the first of a series of
* three holes that can potentially all be merged together.
*/
register struct hole *next_ptr;
/* If 'hp' points to the last hole, no merging is possible. If it does not,
* try to absorb its successor into it and free the successor's table entry.
*/
if ( (next_ptr = hp->h_next) == NIL_HOLE) return;
if (hp->h_base + hp->h_len == next_ptr->h_base) {
hp->h_len += next_ptr->h_len; /* first one gets second one's mem */
del_slot(hp, next_ptr);
} else {
hp = next_ptr;
}
/* If 'hp' now points to the last hole, return; otherwise, try to absorb its
* successor into it.
*/
if ( (next_ptr = hp->h_next) == NIL_HOLE) return;
if (hp->h_base + hp->h_len == next_ptr->h_base) {
hp->h_len += next_ptr->h_len;
del_slot(hp, next_ptr);
}
}
/*===========================================================================*
* mem_init *
*===========================================================================*/
PUBLIC void mem_init(chunks)
struct memory *chunks; /* list of free memory chunks */
{
/* Initialize hole lists. There are two lists: 'hole_head' points to a linked
* list of all the holes (unused memory) in the system; 'free_slots' points to
* a linked list of table entries that are not in use. Initially, the former
* list has one entry for each chunk of physical memory, and the second
* list links together the remaining table slots. As memory becomes more
* fragmented in the course of time (i.e., the initial big holes break up into
* smaller holes), new table slots are needed to represent them. These slots
* are taken from the list headed by 'free_slots'.
*/
int i, first = 0;
register struct hole *hp;
int nodes, largest;
/* Put all holes on the free list. */
for (hp = &hole[0]; hp < &hole[_NR_HOLES]; hp++) {
hp->h_next = hp + 1;
hp->h_base = hp->h_len = 0;
}
hole[_NR_HOLES-1].h_next = NIL_HOLE;
hole_head = NIL_HOLE;
free_slots = &hole[0];
addr_init(&addravl);
total_pages = 0;
/* Use the chunks of physical memory to allocate holes. */
for (i=NR_MEMS-1; i>=0; i--) {
if (chunks[i].size > 0) {
phys_bytes from = CLICK2ABS(chunks[i].base),
to = CLICK2ABS(chunks[i].base+chunks[i].size)-1;
if(first || from < mem_low) mem_low = from;
if(first || to > mem_high) mem_high = to;
free_mem(chunks[i].base, chunks[i].size);
total_pages += chunks[i].size;
first = 0;
}
}
CHECKHOLES;
}
#if SANITYCHECKS
PRIVATE void sanitycheck(void)
{
pagerange_t *p, *prevp = NULL;
addr_iter iter;
addr_start_iter_least(&addravl, &iter);
while((p=addr_get_iter(&iter))) {
SLABSANE(p);
assert(p->size > 0);
if(prevp) {
assert(prevp->addr < p->addr);
assert(prevp->addr + p->addr < p->addr);
}
addr_incr_iter(&iter);
}
}
#endif
PUBLIC void memstats(int *nodes, int *pages, int *largest)
{
pagerange_t *p, *prevp = NULL;
addr_iter iter;
addr_start_iter_least(&addravl, &iter);
*nodes = 0;
*pages = 0;
*largest = 0;
#if SANITYCHECKS
sanitycheck();
#endif
while((p=addr_get_iter(&iter))) {
SLABSANE(p);
(*nodes)++;
(*pages)+= p->size;
if(p->size > *largest)
*largest = p->size;
addr_incr_iter(&iter);
}
}
/*===========================================================================*
* alloc_pages *
*===========================================================================*/
PRIVATE PUBLIC phys_bytes alloc_pages(int pages, int memflags, phys_bytes *len)
{
addr_iter iter;
pagerange_t *pr;
int incr;
phys_bytes boundary16 = 16 * 1024 * 1024 / VM_PAGE_SIZE;
phys_bytes boundary1 = 1 * 1024 * 1024 / VM_PAGE_SIZE;
phys_bytes mem;
#if SANITYCHECKS
int firstnodes, firstpages, wantnodes, wantpages;
int finalnodes, finalpages;
int largest;
memstats(&firstnodes, &firstpages, &largest);
sanitycheck();
wantnodes = firstnodes;
wantpages = firstpages - pages;
#endif
if(memflags & (PAF_LOWER16MB|PAF_LOWER1MB)) {
addr_start_iter_least(&addravl, &iter);
incr = 1;
} else {
addr_start_iter_greatest(&addravl, &iter);
incr = 0;
}
while((pr = addr_get_iter(&iter))) {
SLABSANE(pr);
assert(pr->size > 0);
if(pr->size >= pages || (memflags & PAF_FIRSTBLOCK)) {
if(memflags & PAF_LOWER16MB) {
if(pr->addr + pages > boundary16)
return NO_MEM;
}
if(memflags & PAF_LOWER1MB) {
if(pr->addr + pages > boundary1)
return NO_MEM;
}
/* good block found! */
break;
}
if(incr)
addr_incr_iter(&iter);
else
addr_decr_iter(&iter);
}
if(!pr) {
printf("VM: alloc_pages: alloc failed of %d pages\n", pages);
util_stacktrace();
printmemstats();
if(len)
*len = 0;
#if SANITYCHECKS
if(largest >= pages) {
panic("no memory but largest was enough");
}
#endif
return NO_MEM;
}
SLABSANE(pr);
if(memflags & PAF_FIRSTBLOCK) {
assert(len);
/* block doesn't have to as big as requested;
* return its size though.
*/
if(pr->size < pages) {
pages = pr->size;
#if SANITYCHECKS
wantpages = firstpages - pages;
#endif
}
}
if(len)
*len = pages;
/* Allocated chunk is off the end. */
mem = pr->addr + pr->size - pages;
assert(pr->size >= pages);
if(pr->size == pages) {
pagerange_t *prr;
prr = addr_remove(&addravl, pr->addr);
assert(prr);
assert(prr == pr);
SLABFREE(pr);
#if SANITYCHECKS
wantnodes--;
#endif
} else {
USE(pr, pr->size -= pages;);
}
if(memflags & PAF_CLEAR) {
int s;
if ((s= sys_memset(0, CLICK_SIZE*mem,
VM_PAGE_SIZE*pages)) != OK)
panic("alloc_mem: sys_memset failed: %d", s);
}
#if SANITYCHECKS
memstats(&finalnodes, &finalpages, &largest);
sanitycheck();
if(finalpages != wantpages) {
printf("pages start: %d req: %d final: %d\n",
firstpages, pages, finalpages);
}
assert(finalnodes == wantnodes);
assert(finalpages == wantpages);
#endif
return mem;
}
/*===========================================================================*
* free_pages *
*===========================================================================*/
PRIVATE void free_pages(phys_bytes pageno, int npages)
{
pagerange_t *pr, *p;
addr_iter iter;
#if SANITYCHECKS
int firstnodes, firstpages, wantnodes, wantpages;
int finalnodes, finalpages, largest;
memstats(&firstnodes, &firstpages, &largest);
sanitycheck();
wantnodes = firstnodes;
wantpages = firstpages + npages;
#endif
assert(!addr_search(&addravl, pageno, AVL_EQUAL));
/* try to merge with higher neighbour */
if((pr=addr_search(&addravl, pageno+npages, AVL_EQUAL))) {
USE(pr, pr->addr -= npages;
pr->size += npages;);
} else {
if(!SLABALLOC(pr))
panic("alloc_pages: can't alloc");
#if SANITYCHECKS
memstats(&firstnodes, &firstpages, &largest);
wantnodes = firstnodes;
wantpages = firstpages + npages;
sanitycheck();
#endif
assert(npages > 0);
USE(pr, pr->addr = pageno;
pr->size = npages;);
addr_insert(&addravl, pr);
#if SANITYCHECKS
wantnodes++;
#endif
}
addr_start_iter(&addravl, &iter, pr->addr, AVL_EQUAL);
p = addr_get_iter(&iter);
assert(p);
assert(p == pr);
addr_decr_iter(&iter);
if((p = addr_get_iter(&iter))) {
SLABSANE(p);
if(p->addr + p->size == pr->addr) {
USE(p, p->size += pr->size;);
addr_remove(&addravl, pr->addr);
SLABFREE(pr);
#if SANITYCHECKS
wantnodes--;
#endif
}
}
#if SANITYCHECKS
memstats(&finalnodes, &finalpages, &largest);
sanitycheck();
assert(finalnodes == wantnodes);
assert(finalpages == wantpages);
#endif
}
#define NR_DMA 16
PRIVATE struct dmatab
{
int dt_flags;
endpoint_t dt_proc;
phys_bytes dt_base;
phys_bytes dt_size;
phys_clicks dt_seg_base;
phys_clicks dt_seg_size;
} dmatab[NR_DMA];
#define DTF_INUSE 1
#define DTF_RELEASE_DMA 2
#define DTF_RELEASE_SEG 4
/*===========================================================================*
* do_adddma *
*===========================================================================*/
PUBLIC int do_adddma(message *msg)
{
endpoint_t req_proc_e, target_proc_e;
int i, proc_n;
phys_bytes base, size;
struct vmproc *vmp;
req_proc_e= msg->VMAD_REQ;
target_proc_e= msg->VMAD_EP;
base= msg->VMAD_START;
size= msg->VMAD_SIZE;
/* Find empty slot */
for (i= 0; i<NR_DMA; i++)
{
if (!(dmatab[i].dt_flags & DTF_INUSE))
break;
}
if (i >= NR_DMA)
{
printf("vm:do_adddma: dma table full\n");
for (i= 0; i<NR_DMA; i++)
{
printf("%d: flags 0x%x proc %d base 0x%x size 0x%x\n",
i, dmatab[i].dt_flags,
dmatab[i].dt_proc,
dmatab[i].dt_base,
dmatab[i].dt_size);
}
panic("adddma: table full");
return ENOSPC;
}
/* Find target process */
if (vm_isokendpt(target_proc_e, &proc_n) != OK)
{
printf("vm:do_adddma: endpoint %d not found\n", target_proc_e);
return EINVAL;
}
vmp= &vmproc[proc_n];
vmp->vm_flags |= VMF_HAS_DMA;
dmatab[i].dt_flags= DTF_INUSE;
dmatab[i].dt_proc= target_proc_e;
dmatab[i].dt_base= base;
dmatab[i].dt_size= size;
return OK;
}
/*===========================================================================*
* do_deldma *
*===========================================================================*/
PUBLIC int do_deldma(message *msg)
{
endpoint_t req_proc_e, target_proc_e;
int i, j, proc_n;
phys_bytes base, size;
struct vmproc *vmp;
req_proc_e= msg->VMDD_REQ;
target_proc_e= msg->VMDD_EP;
base= msg->VMDD_START;
size= msg->VMDD_SIZE;
/* Find slot */
for (i= 0; i<NR_DMA; i++)
{
if (!(dmatab[i].dt_flags & DTF_INUSE))
continue;
if (dmatab[i].dt_proc == target_proc_e &&
dmatab[i].dt_base == base &&
dmatab[i].dt_size == size)
{
break;
}
}
if (i >= NR_DMA)
{
printf("vm:do_deldma: slot not found\n");
return ESRCH;
}
if (dmatab[i].dt_flags & DTF_RELEASE_SEG)
{
/* Check if we have to release the segment */
for (j= 0; j<NR_DMA; j++)
{
if (j == i)
continue;
if (!(dmatab[j].dt_flags & DTF_INUSE))
continue;
if (!(dmatab[j].dt_flags & DTF_RELEASE_SEG))
continue;
if (dmatab[i].dt_proc == target_proc_e)
break;
}
if (j >= NR_DMA)
{
/* Last segment */
free_mem(dmatab[i].dt_seg_base,
dmatab[i].dt_seg_size);
}
}
dmatab[i].dt_flags &= ~DTF_INUSE;
return OK;
}
/*===========================================================================*
* do_getdma *
*===========================================================================*/
PUBLIC int do_getdma(message *msg)
{
endpoint_t target_proc_e;
int i, proc_n;
phys_bytes base, size;
struct vmproc *vmp;
/* Find slot to report */
for (i= 0; i<NR_DMA; i++)
{
if (!(dmatab[i].dt_flags & DTF_INUSE))
continue;
if (!(dmatab[i].dt_flags & DTF_RELEASE_DMA))
continue;
printf("do_getdma: setting reply to 0x%x@0x%x proc %d\n",
dmatab[i].dt_size, dmatab[i].dt_base,
dmatab[i].dt_proc);
msg->VMGD_PROCP= dmatab[i].dt_proc;
msg->VMGD_BASEP= dmatab[i].dt_base;
msg->VMGD_SIZEP= dmatab[i].dt_size;
return OK;
}
/* Nothing */
return EAGAIN;
}
/*===========================================================================*
* release_dma *
*===========================================================================*/
PUBLIC void release_dma(struct vmproc *vmp)
{
int i, found_one;
panic("release_dma not done");
#if 0
found_one= FALSE;
for (i= 0; i<NR_DMA; i++)
{
if (!(dmatab[i].dt_flags & DTF_INUSE))
continue;
if (dmatab[i].dt_proc != vmp->vm_endpoint)
continue;
dmatab[i].dt_flags |= DTF_RELEASE_DMA | DTF_RELEASE_SEG;
dmatab[i].dt_seg_base= base;
dmatab[i].dt_seg_size= size;
found_one= TRUE;
}
if (!found_one)
free_mem(base, size);
msg->VMRD_FOUND = found_one;
#endif
return;
}
/*===========================================================================*
* printmemstats *
*===========================================================================*/
void printmemstats(void)
{
int nodes, pages, largest;
memstats(&nodes, &pages, &largest);
printf("%d blocks, %d pages (%ukB) free, largest %d pages (%ukB)\n",
nodes, pages, (u32_t) pages * (VM_PAGE_SIZE/1024),
largest, (u32_t) largest * (VM_PAGE_SIZE/1024));
}
#if SANITYCHECKS
/*===========================================================================*
* usedpages_reset *
*===========================================================================*/
void usedpages_reset(void)
{
memset(pagemap, 0, sizeof(pagemap));
}
/*===========================================================================*
* usedpages_add *
*===========================================================================*/
int usedpages_add_f(phys_bytes addr, phys_bytes len, char *file, int line)
{
pagerange_t *pr;
u32_t pagestart, pages;
if(!incheck)
return OK;
assert(!(addr % VM_PAGE_SIZE));
assert(!(len % VM_PAGE_SIZE));
assert(len > 0);
assert_range(addr, len);
pagestart = addr / VM_PAGE_SIZE;
pages = len / VM_PAGE_SIZE;
while(pages > 0) {
phys_bytes thisaddr;
assert(pagestart > 0);
assert(pagestart < MAXPAGES);
thisaddr = pagestart * VM_PAGE_SIZE;
if(GET_BIT(pagemap, pagestart)) {
int i;
printf("%s:%d: usedpages_add: addr 0x%lx reused.\n",
file, line, thisaddr);
return EFAULT;
}
SET_BIT(pagemap, pagestart);
pages--;
pagestart++;
}
return OK;
}
#endif
/*===========================================================================*
* alloc_mem_in_list *
*===========================================================================*/
struct memlist *alloc_mem_in_list(phys_bytes bytes, u32_t flags)
{
phys_bytes rempages;
struct memlist *head = NULL, *ml;
assert(bytes > 0);
assert(!(bytes % VM_PAGE_SIZE));
rempages = bytes / VM_PAGE_SIZE;
/* unless we are told to allocate all memory
* contiguously, tell alloc function to grab whatever
* block it can find.
*/
if(!(flags & PAF_CONTIG))
flags |= PAF_FIRSTBLOCK;
do {
struct memlist *ml;
phys_bytes mem, gotpages;
mem = alloc_pages(rempages, flags, &gotpages);
if(mem == NO_MEM) {
free_mem_list(head, 1);
return NULL;
}
assert(gotpages <= rempages);
assert(gotpages > 0);
if(!(SLABALLOC(ml))) {
free_mem_list(head, 1);
free_pages(mem, gotpages);
return NULL;
}
USE(ml,
ml->phys = CLICK2ABS(mem);
ml->length = CLICK2ABS(gotpages);
ml->next = head;);
head = ml;
rempages -= gotpages;
} while(rempages > 0);
for(ml = head; ml; ml = ml->next) {
assert(ml->phys);
assert(ml->length);
}
return head;
}
/*===========================================================================*
* free_mem_list *
*===========================================================================*/
void free_mem_list(struct memlist *list, int all)
{
while(list) {
struct memlist *next;
next = list->next;
assert(!(list->phys % VM_PAGE_SIZE));
assert(!(list->length % VM_PAGE_SIZE));
if(all)
free_pages(list->phys / VM_PAGE_SIZE,
list->length / VM_PAGE_SIZE);
SLABFREE(list);
list = next;
}
}
/*===========================================================================*
* print_mem_list *
*===========================================================================*/
void print_mem_list(struct memlist *list)
{
while(list) {
assert(list->length > 0);
printf("0x%lx-0x%lx", list->phys, list->phys+list->length-1);
printf(" ");
list = list->next;
}
printf("\n");
}
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