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/*******************************************
*
* Copyright 2001, Red Hat, Inc., all rights reserved.
*
* Author: Bob Matthews <bmatthews@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*******************************************/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include "sysinfo.h"
#include "mem_load.h"
#include "programs.h"
#include "trivial.h"
int *grab_and_touch (char *block[], int i)
{
block[i] = (char *) malloc (MB);
if (!block[i])
return NULL;
return (memset (block[i], 1, MB));
}
/* OK, this is very tricky and full of assumptions.
*
* In most cases, we allocate 110% of RAM, minus DEFAULT_RESERVE, which is the minimum amount
* required for the kernel and its data. Best guesstimates by Those Who Know puts this at
* around 64M for UP and SMP kernels, and 256M for enterprise kernels, although it will
* certainly vary widely depending upon the job mix running on the machine.
*
* If the machine doesn't have the proper amount of swap (or has no swap at all) we just
* allocate as much as we can, minus the DEFAULT_RESERVE.
*
* Also, we need to take care and make sure we don't tell the program that it can
* access memory beyond 3G. That's currently the per process limit on the brk area (I think.)
*/
unsigned long compute_allocable_mem (unsigned long ram, unsigned long swap, int percent_ram)
{
unsigned long total = ram + swap;
unsigned long usage = ram * percent_ram / 100 ;
/* Leave at least DEFAULT_RESERVE free space and check for maths overflow. */
usage = MIN(usage, total - DEFAULT_RESERVE);
usage/=1024; /* to megabytes */
return MIN(usage, 2930);
}
int do_mem_load(void)
{
unsigned long ram, swap, touchable_mem, i;
char *mem_block[MAX_MEM_IN_MB];
void *success;
int iterations=0;
int j=0, percent_ram=110;
if(get_ram(&ram)){
printsys("could not get info on ram size, aborting\n");
}
if(get_swap(&swap)){
printsys("could not get info on ram size, aborting\n");
}
/* obviously does nothing, but left as documentation - aggelos */
if (! (j < 10 || j >110))
percent_ram=j;
printd("ram=%lu, swap=%lu\n", ram, swap);
/* determine if how much ram we want to touch */
touchable_mem = compute_allocable_mem (ram, swap, percent_ram);
printd("touchable mem=%lu\n", touchable_mem);
/* loop until we're killed, frobbing memory in various perverted ways */
for ( ; ; ) {
/* grab and touch MB blocks of memory until we have what we want */
for (i = 0; i < touchable_mem; i++) {
if(++iterations == 10){
report_progress();
iterations=0;
}
success = grab_and_touch(mem_block, i);
if (!success) {
/*
* freebsd returns NULL too early
* (or rather just in time)
*/
printd("Can't grab and/or touch mem_block "
"%lu\n", i);
touchable_mem=i-1;
break;
}
}
for (i = 0; i < touchable_mem; i++) {
if(++iterations==10){
report_progress();
iterations=0;
}
printd("Moving block %lu to %ld\n", i, (i + touchable_mem / 2) % touchable_mem);
memcpy (mem_block[i], mem_block[(i + touchable_mem / 2) % touchable_mem], MB);
}
for (i = touchable_mem - 1; i != ~0UL; i--) {
if(++iterations==10){
report_progress();
iterations=0;
}
memcpy (mem_block[(i + touchable_mem / 2) % touchable_mem], mem_block[i], MB);
}
for (i = 0; i < touchable_mem; i++) {
if(++iterations==10){
report_progress();
iterations=0;
}
free (mem_block[i]);
}
}
/* not reached */
exit (0);
}
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