Oren Laadan wrote:
>> Oren,
>>
>> Could you take a look over Cedric's external checkpoint patch?
>>
>> http://git.kernel.org/?p=linux/kernel/git/daveh/linux-2.6-cr.git;a=commit;h=28ffabbc17d3641eee2a7eb66f714c266c400263
>>
>> It seems pretty small to me.
>>
>> --
>
> I committed a couple of patches on top of ckpt-v7 that do this.
> (the first one is actually a simple cleanup that is unrelated).
>
> see:
> http://git.ncl.cs.columbia.edu/?p=linux-cr-dev.git;a=shortlog;h=refs/heads/ckpt-v7
> (or git://git.ncl.cs.columbia.edu/pub/git/linux-cr-dev.git ckpt-v7)
>
> * "Minor simplification of cr_ctx_alloc(), cr_ctx_free()"
> * "External checkpoint of a task other than ourself"
>
> To checkpoint another task, you need to freeze that other task, or to
> SIGSTOP it (if using a kernel without freezer cgroup).
>
> Restart remains the same except the the original PID is not preserved
> (because we haven't solved yet the fork-with-specific-pid issue).
>
> In reality, you would create a new names space, and have the task running
> in there call 'sys_restart()'.
>
> Below are test1.c, ckpt.c (to checkpoint), and rstr.c (to restart), as
> well as the two patches.
>
> I tested it this way:
> $ ./test.1 &
> [1] 3493
>
> $ kill -STOP 3493
> $ ./ckpt 3493 > ckpt.image
>
> $ mv /tmp/cr-test.out /tmp/cr-test.out.orig
> $ cp /tmp/cr-test.out.orig /tmp/cr-test.out
>
> $ kill -CONT 3493
>
> $ ./rstr < ckpt.image
> now compare the output of the two output files
Oren,
I've merged your v7 patches on top of the 2.6.27-lxc3 patchset :
http://lxc.sourceforge.net/patches/2.6.27/2.6.27-lxc3/
the -lxc patchset includes the just merged freezer and sysfs patches
required for the netns.
the lxc user tools using the patchset are here (CVS head for the
moment) :
http://sourceforge.net/projects/lxc/
simple applications calculating decimals of PI (source attached) are
successfully checkpointed and restarted with the lxc-checkpoint and
lxc-restart tools. something like the following :
$ lxc-create -n foo
$ lxc-start -n foo ./pi1 40000 &
$ lxc-checkpoint -n foo > /tmp/statefile
$ lxc-restart -n foo < /tmp/statefile
stdin should be closed of course and all output redirected to a regular
file.
This is work in progress of course but it's a major milestone !
Thanks,
C.
/****************************************/
/* Compute pi to arbitrary precision */
/* Author Roy Williams February 1994 */
/* roy@xxxxxxxxxxxxxxxx */
/* Uses Machin's formula... */
/* pi/4 = 4 arctan(1/5) - arctan(1/239) */
/****************************************/
/* compile with cc -O -o pi pi.c */
/* run as "pi 1000" for 1000 digits */
/****************************************/
/* The last few digits may be wrong.......... */
#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <unistd.h>
void arctan(int *result, int *w1, int *w2, int denom, int onestep);
void mult(int *result, int factor);
void sub(int *result, int *decrem);
void print(int *result);
void mdiv(int *result, int denom);
void set(int *result, int rhs);
void copy(int *result, int *from);
void add(int *result, int *increm);
int zero(int *result);
#define BASE 10000
int nblock;
int *tot;
int *t1;
int *t2;
int *t3;
int main(int argc, char **argv)
{
int ndigit = 60;
if(argc == 2)
ndigit = atoi(argv[1]);
else {
fprintf(stderr, "Usage: %s ndigit\n", argv[0]);
fprintf(stderr, "(Assuming 60 digits)\n");
}
if(ndigit < 20) ndigit = 20;
nblock = ndigit/4;
tot = (int *)malloc(nblock*sizeof(int));
t1 = (int *)malloc(nblock*sizeof(int));
t2 = (int *)malloc(nblock*sizeof(int));
t3 = (int *)malloc(nblock*sizeof(int));
if(!tot || !t1 || !t2 || !t3){
fprintf(stderr, "Not enough memory\n");
exit(1);
}
printf("pi1 - %d digits, %.1f kbytes\n", ndigit,
(4*nblock*sizeof(int))/1024.0);
arctan(tot, t1, t2, 5, 1);
mult(tot, 4);
arctan(t3, t1, t2, 239, 2);
sub(tot, t3);
mult(tot, 4);
print(tot);
return 0;
}
void arctan(int *result, int *w1, int *w2, int denom, int onestep)
{
int denom2 = denom*denom;
int k = 1;
set(result, 1);
mdiv(result, denom);
copy(w1, result);
do{
if(onestep)
mdiv(w1, denom2);
else {
mdiv(w1, denom);
mdiv(w1, denom);
}
copy(w2, w1);
mdiv(w2, 2*k+1);
if(k%2)
sub(result, w2);
else
add(result, w2);
k++;
// add tracing PG
//printf(":%d\n",k);
} while(!zero(w2));
}
void copy(int *result, int *from)
{
int i;
for(i=0; i<nblock; i++)
result[i] = from[i];
}
int zero(int *result)
{
int i;
for(i=0; i<nblock; i++)
if(result[i])
return 0;
return 1;
}
void add(int *result, int *increm)
{
int i;
for(i=nblock-1; i>=0; i--){
result[i] += increm[i];
if(result[i] >= BASE){
result[i] -= BASE;
result[i-1]++;
}
}
}
void sub(int *result, int *decrem)
{
int i;
for(i=nblock-1; i>=0; i--){
result[i] -= decrem[i];
if(result[i] < 0){
result[i] += BASE;
result[i-1]--;
}
}
}
void mult(int *result, int factor)
{
int i, carry = 0;
for(i=nblock-1; i>=0; i--){
result[i] *= factor;
result[i] += carry;
carry = result[i]/BASE;
result[i] %= BASE;
}
}
void mdiv(int *result, int denom)
{
int i, carry = 0;
for(i=0; i<nblock; i++){
result[i] += carry*BASE;
carry = result[i] % denom;
result[i] /= denom;
}
}
void set(int *result, int rhs)
{
int i;
for(i=0; i<nblock; i++)
result[i] = 0;
result[0] = rhs;
}
void print(int *result)
{
int i, k;
char s[10];
printf("%1d.\n", result[0]);
for(i=1; i<nblock; i++){
sprintf(s, "%4d ", result[i]);
for(k=0; k<5; k++)
if(s[k] == ' ') s[k] = '0';
printf("%c%c%c%c", s[0], s[1], s[2], s[3]);
if(i%15 == 0) printf("\n");
}
printf("\n");
}
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