19e6dad47b
. only reference single pages in process data structures to simplify page faults, copy-on-write, etc. . this breaks the secondary cache for objects that are not one-page-sized; restored in a next commit
474 lines
12 KiB
C
474 lines
12 KiB
C
/* This file is concerned with allocating and freeing arbitrary-size blocks of
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* physical memory.
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*/
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#define _SYSTEM 1
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#include <minix/com.h>
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#include <minix/callnr.h>
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#include <minix/type.h>
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#include <minix/config.h>
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#include <minix/const.h>
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#include <minix/sysutil.h>
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#include <minix/syslib.h>
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#include <minix/debug.h>
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#include <minix/bitmap.h>
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#include <sys/mman.h>
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#include <limits.h>
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#include <string.h>
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#include <errno.h>
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#include <assert.h>
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#include <memory.h>
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#include "vm.h"
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#include "proto.h"
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#include "util.h"
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#include "glo.h"
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#include "sanitycheck.h"
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#include "memlist.h"
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/* Number of physical pages in a 32-bit address space */
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#define NUMBER_PHYSICAL_PAGES (0x100000000ULL/VM_PAGE_SIZE)
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#define PAGE_BITMAP_CHUNKS BITMAP_CHUNKS(NUMBER_PHYSICAL_PAGES)
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static bitchunk_t free_pages_bitmap[PAGE_BITMAP_CHUNKS];
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#define PAGE_CACHE_MAX 10000
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static int free_page_cache[PAGE_CACHE_MAX];
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static int free_page_cache_size = 0;
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/* Used for sanity check. */
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static phys_bytes mem_low, mem_high;
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static void free_pages(phys_bytes addr, int pages);
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static phys_bytes alloc_pages(int pages, int flags);
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#if SANITYCHECKS
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struct {
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int used;
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char *file;
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int line;
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} pagemap[NUMBER_PHYSICAL_PAGES];
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#endif
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#define page_isfree(i) GET_BIT(free_pages_bitmap, i)
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/*===========================================================================*
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* alloc_mem *
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*===========================================================================*/
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phys_clicks alloc_mem(phys_clicks clicks, u32_t memflags)
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{
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/* Allocate a block of memory from the free list using first fit. The block
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* consists of a sequence of contiguous bytes, whose length in clicks is
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* given by 'clicks'. A pointer to the block is returned. The block is
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* always on a click boundary. This procedure is called when memory is
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* needed for FORK or EXEC.
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*/
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phys_clicks mem = NO_MEM, align_clicks = 0;
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if(memflags & PAF_ALIGN64K) {
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align_clicks = (64 * 1024) / CLICK_SIZE;
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clicks += align_clicks;
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} else if(memflags & PAF_ALIGN16K) {
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align_clicks = (16 * 1024) / CLICK_SIZE;
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clicks += align_clicks;
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}
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mem = alloc_pages(clicks, memflags);
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if(mem == NO_MEM) {
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free_yielded(clicks * CLICK_SIZE);
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mem = alloc_pages(clicks, memflags);
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}
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if(mem == NO_MEM)
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return mem;
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if(align_clicks) {
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phys_clicks o;
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o = mem % align_clicks;
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if(o > 0) {
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phys_clicks e;
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e = align_clicks - o;
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free_mem(mem, e);
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mem += e;
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}
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}
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return mem;
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}
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/*===========================================================================*
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* free_mem *
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*===========================================================================*/
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void free_mem(phys_clicks base, phys_clicks clicks)
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{
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/* Return a block of free memory to the hole list. The parameters tell where
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* the block starts in physical memory and how big it is. The block is added
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* to the hole list. If it is contiguous with an existing hole on either end,
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* it is merged with the hole or holes.
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*/
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if (clicks == 0) return;
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assert(CLICK_SIZE == VM_PAGE_SIZE);
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free_pages(base, clicks);
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return;
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}
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/*===========================================================================*
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* mem_init *
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*===========================================================================*/
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void mem_init(chunks)
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struct memory *chunks; /* list of free memory chunks */
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{
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/* Initialize hole lists. There are two lists: 'hole_head' points to a linked
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* list of all the holes (unused memory) in the system; 'free_slots' points to
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* a linked list of table entries that are not in use. Initially, the former
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* list has one entry for each chunk of physical memory, and the second
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* list links together the remaining table slots. As memory becomes more
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* fragmented in the course of time (i.e., the initial big holes break up into
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* smaller holes), new table slots are needed to represent them. These slots
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* are taken from the list headed by 'free_slots'.
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*/
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int i, first = 0;
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total_pages = 0;
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memset(free_pages_bitmap, 0, sizeof(free_pages_bitmap));
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/* Use the chunks of physical memory to allocate holes. */
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for (i=NR_MEMS-1; i>=0; i--) {
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if (chunks[i].size > 0) {
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phys_bytes from = CLICK2ABS(chunks[i].base),
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to = CLICK2ABS(chunks[i].base+chunks[i].size)-1;
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if(first || from < mem_low) mem_low = from;
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if(first || to > mem_high) mem_high = to;
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free_mem(chunks[i].base, chunks[i].size);
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total_pages += chunks[i].size;
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first = 0;
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}
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}
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}
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#if SANITYCHECKS
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void mem_sanitycheck(char *file, int line)
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{
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int i;
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for(i = 0; i < NUMBER_PHYSICAL_PAGES; i++) {
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if(!page_isfree(i)) continue;
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MYASSERT(usedpages_add(i * VM_PAGE_SIZE, VM_PAGE_SIZE) == OK);
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}
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}
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#endif
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void memstats(int *nodes, int *pages, int *largest)
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{
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int i;
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*nodes = 0;
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*pages = 0;
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*largest = 0;
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for(i = 0; i < NUMBER_PHYSICAL_PAGES; i++) {
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int size = 0;
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while(i < NUMBER_PHYSICAL_PAGES && page_isfree(i)) {
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size++;
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i++;
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}
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if(size == 0) continue;
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(*nodes)++;
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(*pages)+= size;
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if(size > *largest)
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*largest = size;
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}
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}
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static int findbit(int low, int startscan, int pages, int memflags, int *len)
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{
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int run_length = 0, i, freerange_start;
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for(i = startscan; i >= low; i--) {
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if(!page_isfree(i)) {
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int pi;
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int chunk = i/BITCHUNK_BITS, moved = 0;
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run_length = 0;
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pi = i;
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while(chunk > 0 &&
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!MAP_CHUNK(free_pages_bitmap, chunk*BITCHUNK_BITS)) {
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chunk--;
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moved = 1;
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}
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if(moved) { i = chunk * BITCHUNK_BITS + BITCHUNK_BITS; }
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continue;
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}
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if(!run_length) { freerange_start = i; run_length = 1; }
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else { freerange_start--; run_length++; }
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assert(run_length <= pages);
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if(run_length == pages) {
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/* good block found! */
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*len = run_length;
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return freerange_start;
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}
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}
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return NO_MEM;
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}
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/*===========================================================================*
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* alloc_pages *
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*===========================================================================*/
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static phys_bytes alloc_pages(int pages, int memflags)
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{
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phys_bytes boundary16 = 16 * 1024 * 1024 / VM_PAGE_SIZE;
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phys_bytes boundary1 = 1 * 1024 * 1024 / VM_PAGE_SIZE;
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phys_bytes mem = NO_MEM;
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int maxpage = NUMBER_PHYSICAL_PAGES - 1, i;
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static int lastscan = -1;
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int startscan, run_length;
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if(memflags & PAF_LOWER16MB)
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maxpage = boundary16 - 1;
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else if(memflags & PAF_LOWER1MB)
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maxpage = boundary1 - 1;
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else {
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/* no position restrictions: check page cache */
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if(pages == 1) {
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while(free_page_cache_size > 0) {
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i = free_page_cache[free_page_cache_size-1];
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if(page_isfree(i)) {
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free_page_cache_size--;
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mem = i;
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assert(mem != NO_MEM);
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run_length = 1;
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break;
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}
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free_page_cache_size--;
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}
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}
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}
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if(lastscan < maxpage && lastscan >= 0)
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startscan = lastscan;
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else startscan = maxpage;
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if(mem == NO_MEM)
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mem = findbit(0, startscan, pages, memflags, &run_length);
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if(mem == NO_MEM)
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mem = findbit(0, maxpage, pages, memflags, &run_length);
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if(mem == NO_MEM)
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return NO_MEM;
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/* remember for next time */
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lastscan = mem;
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for(i = mem; i < mem + pages; i++) {
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UNSET_BIT(free_pages_bitmap, i);
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}
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if(memflags & PAF_CLEAR) {
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int s;
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if ((s= sys_memset(NONE, 0, CLICK_SIZE*mem,
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VM_PAGE_SIZE*pages)) != OK)
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panic("alloc_mem: sys_memset failed: %d", s);
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}
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return mem;
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}
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/*===========================================================================*
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* free_pages *
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*===========================================================================*/
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static void free_pages(phys_bytes pageno, int npages)
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{
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int i, lim = pageno + npages - 1;
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#if JUNKFREE
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if(sys_memset(NONE, 0xa5a5a5a5, VM_PAGE_SIZE * pageno,
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VM_PAGE_SIZE * npages) != OK)
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panic("free_pages: sys_memset failed");
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#endif
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for(i = pageno; i <= lim; i++) {
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SET_BIT(free_pages_bitmap, i);
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if(free_page_cache_size < PAGE_CACHE_MAX) {
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free_page_cache[free_page_cache_size++] = i;
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}
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}
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}
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/*===========================================================================*
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* printmemstats *
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*===========================================================================*/
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void printmemstats(void)
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{
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int nodes, pages, largest;
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memstats(&nodes, &pages, &largest);
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printf("%d blocks, %d pages (%lukB) free, largest %d pages (%lukB)\n",
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nodes, pages, (unsigned long) pages * (VM_PAGE_SIZE/1024),
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largest, (unsigned long) largest * (VM_PAGE_SIZE/1024));
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}
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#if SANITYCHECKS
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/*===========================================================================*
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* usedpages_reset *
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*===========================================================================*/
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void usedpages_reset(void)
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{
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memset(pagemap, 0, sizeof(pagemap));
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}
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/*===========================================================================*
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* usedpages_add *
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*===========================================================================*/
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int usedpages_add_f(phys_bytes addr, phys_bytes len, char *file, int line)
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{
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u32_t pagestart, pages;
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if(!incheck)
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return OK;
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assert(!(addr % VM_PAGE_SIZE));
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assert(!(len % VM_PAGE_SIZE));
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assert(len > 0);
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pagestart = addr / VM_PAGE_SIZE;
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pages = len / VM_PAGE_SIZE;
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while(pages > 0) {
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phys_bytes thisaddr;
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assert(pagestart > 0);
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assert(pagestart < NUMBER_PHYSICAL_PAGES);
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thisaddr = pagestart * VM_PAGE_SIZE;
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assert(pagestart >= 0);
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assert(pagestart < NUMBER_PHYSICAL_PAGES);
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if(pagemap[pagestart].used) {
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static int warnings = 0;
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if(warnings++ < 100)
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printf("%s:%d: usedpages_add: addr 0x%lx reused, first %s:%d\n",
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file, line, thisaddr, pagemap[pagestart].file, pagemap[pagestart].line);
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util_stacktrace();
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return EFAULT;
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}
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pagemap[pagestart].used = 1;
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pagemap[pagestart].file = file;
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pagemap[pagestart].line = line;
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pages--;
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pagestart++;
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}
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return OK;
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}
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#endif
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/*===========================================================================*
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* alloc_mem_in_list *
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*===========================================================================*/
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struct memlist *alloc_mem_in_list(phys_bytes bytes, u32_t flags, phys_bytes known)
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{
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phys_bytes rempages, phys_count;
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struct memlist *head = NULL, *tail = NULL;
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assert(bytes > 0);
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assert(!(bytes % VM_PAGE_SIZE));
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rempages = bytes / VM_PAGE_SIZE;
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assert(!(flags & PAF_CONTIG));
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if(known != MAP_NONE)
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phys_count = known;
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do {
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struct memlist *ml;
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phys_bytes mem;
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vir_bytes freed = 0;
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do {
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if(known == MAP_NONE) {
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mem = alloc_pages(1, flags);
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if(mem == NO_MEM) {
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freed = free_yielded(rempages * VM_PAGE_SIZE);
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}
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assert(mem != MAP_NONE);
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} else {
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mem = ABS2CLICK(phys_count);
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phys_count += VM_PAGE_SIZE;
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assert(mem != MAP_NONE);
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assert(mem != NO_MEM);
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}
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assert(mem != MAP_NONE);
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} while(mem == NO_MEM && freed > 0);
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if(mem == NO_MEM) {
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printf("alloc_mem_in_list: giving up, %lukB missing\n",
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rempages * VM_PAGE_SIZE/1024);
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printmemstats();
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free_mem_list(head, 1);
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return NULL;
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}
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if(!(SLABALLOC(ml))) {
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free_mem_list(head, 1);
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free_pages(mem, VM_PAGE_SIZE);
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return NULL;
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}
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USE(ml, ml->phys = CLICK2ABS(mem); ml->next = NULL;);
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if(tail) {
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USE(tail,
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tail->next = ml;);
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}
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tail = ml;
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if(!head)
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head = ml;
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rempages--;
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} while(rempages > 0);
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{
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struct memlist *ml;
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for(ml = head; ml; ml = ml->next) {
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assert(ml->phys);
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#if NONCONTIGUOUS
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if(!(flags & PAF_CONTIG)) {
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if(ml->next)
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assert(ml->phys + ml->length != ml->next->phys);
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}
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#endif
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}
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}
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return head;
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}
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/*===========================================================================*
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* free_mem_list *
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*===========================================================================*/
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void free_mem_list(struct memlist *list, int all)
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{
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while(list) {
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struct memlist *next;
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next = list->next;
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assert(!(list->phys % VM_PAGE_SIZE));
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if(all)
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free_pages(list->phys / VM_PAGE_SIZE, 1);
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SLABFREE(list);
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list = next;
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}
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}
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/*===========================================================================*
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* print_mem_list *
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*===========================================================================*/
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void print_mem_list(struct memlist *list)
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{
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while(list) {
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printf("0x%lx-0x%lx", list->phys, list->phys+VM_PAGE_SIZE-1);
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printf(" ");
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list = list->next;
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}
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printf("\n");
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}
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