minix/servers/vm/alloc.c
Lionel Sambuc 0ac803292e Fix warnings trivial warnings.
Fix warnings about:
 . Unused variables
 . format mismatch in printf/scanf format string and arguments
 . Missing parenthesis around assignment as truth values
 . Clang warnings anout unknown GCC pragma
2013-01-14 11:44:31 +01:00

364 lines
9.6 KiB
C

/* This file is concerned with allocating and freeing arbitrary-size blocks of
* physical memory.
*/
#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 "sanitycheck.h"
#include "memlist.h"
/* Number of physical pages in a 32-bit address space */
#define NUMBER_PHYSICAL_PAGES (0x100000000ULL/VM_PAGE_SIZE)
#define PAGE_BITMAP_CHUNKS BITMAP_CHUNKS(NUMBER_PHYSICAL_PAGES)
static bitchunk_t free_pages_bitmap[PAGE_BITMAP_CHUNKS];
#define PAGE_CACHE_MAX 10000
static int free_page_cache[PAGE_CACHE_MAX];
static int free_page_cache_size = 0;
/* Used for sanity check. */
static phys_bytes mem_low, mem_high;
static void free_pages(phys_bytes addr, int pages);
static phys_bytes alloc_pages(int pages, int flags);
#if SANITYCHECKS
struct {
int used;
char *file;
int line;
} pagemap[NUMBER_PHYSICAL_PAGES];
#endif
#define page_isfree(i) GET_BIT(free_pages_bitmap, i)
/*===========================================================================*
* alloc_mem *
*===========================================================================*/
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.
*/
phys_clicks mem = NO_MEM, align_clicks = 0;
if(memflags & PAF_ALIGN64K) {
align_clicks = (64 * 1024) / CLICK_SIZE;
clicks += align_clicks;
} else if(memflags & PAF_ALIGN16K) {
align_clicks = (16 * 1024) / CLICK_SIZE;
clicks += align_clicks;
}
mem = alloc_pages(clicks, memflags);
if(mem == NO_MEM) {
free_yielded(clicks * CLICK_SIZE);
mem = alloc_pages(clicks, memflags);
}
if(mem == NO_MEM)
return mem;
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;
}
}
return mem;
}
/*===========================================================================*
* free_mem *
*===========================================================================*/
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.
*/
if (clicks == 0) return;
assert(CLICK_SIZE == VM_PAGE_SIZE);
free_pages(base, clicks);
return;
}
/*===========================================================================*
* mem_init *
*===========================================================================*/
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;
total_pages = 0;
memset(free_pages_bitmap, 0, sizeof(free_pages_bitmap));
/* 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;
}
}
}
#if SANITYCHECKS
void mem_sanitycheck(char *file, int line)
{
int i;
for(i = 0; i < NUMBER_PHYSICAL_PAGES; i++) {
if(!page_isfree(i)) continue;
MYASSERT(usedpages_add(i * VM_PAGE_SIZE, VM_PAGE_SIZE) == OK);
}
}
#endif
void memstats(int *nodes, int *pages, int *largest)
{
int i;
*nodes = 0;
*pages = 0;
*largest = 0;
for(i = 0; i < NUMBER_PHYSICAL_PAGES; i++) {
int size = 0;
while(i < NUMBER_PHYSICAL_PAGES && page_isfree(i)) {
size++;
i++;
}
if(size == 0) continue;
(*nodes)++;
(*pages)+= size;
if(size > *largest)
*largest = size;
}
}
static int findbit(int low, int startscan, int pages, int memflags, int *len)
{
int run_length = 0, i;
int freerange_start = startscan;
for(i = startscan; i >= low; i--) {
if(!page_isfree(i)) {
int pi;
int chunk = i/BITCHUNK_BITS, moved = 0;
run_length = 0;
pi = i;
while(chunk > 0 &&
!MAP_CHUNK(free_pages_bitmap, chunk*BITCHUNK_BITS)) {
chunk--;
moved = 1;
}
if(moved) { i = chunk * BITCHUNK_BITS + BITCHUNK_BITS; }
continue;
}
if(!run_length) { freerange_start = i; run_length = 1; }
else { freerange_start--; run_length++; }
assert(run_length <= pages);
if(run_length == pages) {
/* good block found! */
*len = run_length;
return freerange_start;
}
}
return NO_MEM;
}
/*===========================================================================*
* alloc_pages *
*===========================================================================*/
static phys_bytes alloc_pages(int pages, int memflags)
{
phys_bytes boundary16 = 16 * 1024 * 1024 / VM_PAGE_SIZE;
phys_bytes boundary1 = 1 * 1024 * 1024 / VM_PAGE_SIZE;
phys_bytes mem = NO_MEM;
int maxpage = NUMBER_PHYSICAL_PAGES - 1, i;
static int lastscan = -1;
int startscan, run_length;
if(memflags & PAF_LOWER16MB)
maxpage = boundary16 - 1;
else if(memflags & PAF_LOWER1MB)
maxpage = boundary1 - 1;
else {
/* no position restrictions: check page cache */
if(pages == 1) {
while(free_page_cache_size > 0) {
i = free_page_cache[free_page_cache_size-1];
if(page_isfree(i)) {
free_page_cache_size--;
mem = i;
assert(mem != NO_MEM);
run_length = 1;
break;
}
free_page_cache_size--;
}
}
}
if(lastscan < maxpage && lastscan >= 0)
startscan = lastscan;
else startscan = maxpage;
if(mem == NO_MEM)
mem = findbit(0, startscan, pages, memflags, &run_length);
if(mem == NO_MEM)
mem = findbit(0, maxpage, pages, memflags, &run_length);
if(mem == NO_MEM)
return NO_MEM;
/* remember for next time */
lastscan = mem;
for(i = mem; i < mem + pages; i++) {
UNSET_BIT(free_pages_bitmap, i);
}
if(memflags & PAF_CLEAR) {
int s;
if ((s= sys_memset(NONE, 0, CLICK_SIZE*mem,
VM_PAGE_SIZE*pages)) != OK)
panic("alloc_mem: sys_memset failed: %d", s);
}
return mem;
}
/*===========================================================================*
* free_pages *
*===========================================================================*/
static void free_pages(phys_bytes pageno, int npages)
{
int i, lim = pageno + npages - 1;
#if JUNKFREE
if(sys_memset(NONE, 0xa5a5a5a5, VM_PAGE_SIZE * pageno,
VM_PAGE_SIZE * npages) != OK)
panic("free_pages: sys_memset failed");
#endif
for(i = pageno; i <= lim; i++) {
SET_BIT(free_pages_bitmap, i);
if(free_page_cache_size < PAGE_CACHE_MAX) {
free_page_cache[free_page_cache_size++] = i;
}
}
}
/*===========================================================================*
* printmemstats *
*===========================================================================*/
void printmemstats(void)
{
int nodes, pages, largest;
memstats(&nodes, &pages, &largest);
printf("%d blocks, %d pages (%lukB) free, largest %d pages (%lukB)\n",
nodes, pages, (unsigned long) pages * (VM_PAGE_SIZE/1024),
largest, (unsigned long) 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)
{
u32_t pagestart, pages;
if(!incheck)
return OK;
assert(!(addr % VM_PAGE_SIZE));
assert(!(len % VM_PAGE_SIZE));
assert(len > 0);
pagestart = addr / VM_PAGE_SIZE;
pages = len / VM_PAGE_SIZE;
while(pages > 0) {
phys_bytes thisaddr;
assert(pagestart > 0);
assert(pagestart < NUMBER_PHYSICAL_PAGES);
thisaddr = pagestart * VM_PAGE_SIZE;
assert(pagestart >= 0);
assert(pagestart < NUMBER_PHYSICAL_PAGES);
if(pagemap[pagestart].used) {
static int warnings = 0;
if(warnings++ < 100)
printf("%s:%d: usedpages_add: addr 0x%lx reused, first %s:%d\n",
file, line, thisaddr, pagemap[pagestart].file, pagemap[pagestart].line);
util_stacktrace();
return EFAULT;
}
pagemap[pagestart].used = 1;
pagemap[pagestart].file = file;
pagemap[pagestart].line = line;
pages--;
pagestart++;
}
return OK;
}
#endif