Re: problem with MAP_SHARED|MAP_ANONYMOUS mapping in openMosix-2.4.26-1

Patch for the problem:

diff -Naur --exclude=CVS --exclude=configs ./old/mm/mmap.c ./new/mm/mmap.c
--- ./old/mm/mmap.c     2005-09-23 14:56:20.000000000 +0530
+++ ./new/mm/mmap.c     2005-09-26 13:57:36.000000000 +0530
@@ -552,6 +552,7 @@
                         vm_flags &= ~(VM_SHARED | VM_MAYSHARE);
                         /* fall through */
                 case MAP_SHARED:
+                       reason_to_come_back |= DSTAY_FOR_MONKEY;
                         break;
                 }
         }

--Ratna Manoj.
On Mon, 26 Sep 2005, Moshe Bar wrote:

> Ratna
>
> Do you have a patch to fix this bug?
>
> Moshe
>
> On 9/25/05, Ratna Manoj Bolla <[email protected]> wrote:
>>
>>
>> Sir,
>>
>> May be you are modifying /proc/pid/migrate manually, in this case -1 will
>> be returned by the write system call because of the condition check in
>> proc_mosix_pid_set_migrate() in hpc/hpcproc.c .
>>
>> 1673 if (task != current)
>> 1674 return (-EPERM);
>>
>>
>> if the process_to_be_migrated, itself (sharing MAP_SHARED|MAP_ANONYMOUS
>> page with some other process) writesB some node no in /proc/pid/migrate
>> then it is migrating(it should not migrate) and giving wrong result.
>>
>> OR if you manually modify /proc/pid/goto, it is migrating.
>>
>> I am attaching the om_test.c which is forking a child and writing a node
>> no in /proc/pid/migrate.
>>
>> Ratna
>>
>> On Sun, 25 Sep 2005, Moshe Bar wrote:
>>
>>> Ratna
>>>
>>> Just tried to recreate the problem and I can't. It's not migrating the
>>> process when I use mmap shared.
>>>
>>> Moshe
>>>
>>> On 9/25/05, Ratna Manoj Bolla <[email protected]> wrote:
>>>>
>>>>
>>>>
>>>>
>> //-----------------------------------------------------------------------------
>>>> #include<stdio.h>
>>>> #include<sys/mman.h>
>>>> #include <sys/types.h>
>>>> #include <sys/stat.h>
>>>> #include <fcntl.h>
>>>> main() {
>>>> int *a =
>>>> mmap(0,4096,PROT_READ|PROT_WRITE,MAP_SHARED|MAP_ANONYMOUS,0,0);
>>>> *a = 0;
>>>> if(fork())
>>>> while(1) { sleep(2); ++(*a); }
>>>> else
>>>> while(1) { printf("%d\n",*a); sleep(2); }
>>>> }
>>>>
>>>>
>>>>
>> //------------------------------------------------------------------------------
>>>>
>>>> The output of this program should be
>>>> 0
>>>> 1
>>>> 2
>>>> 3
>>>> .
>>>> .
>>>>
>>>> but output would remain constant after migrating one of the processes.
>>>>
>>>> openMosix shold not allow migrating processes sharing
>>>> MAP_SHARED|MAP_ANONYMOUS pages.
>>>>
>>>> from,
>>>> Ratna Manoj Bolla,
>>>> M.Tech IInd year,
>>>> dept. of CSE,
>>>> Indian Institute of Technology,
>>>> Guwahati,
>>>> India.
>>>>
>>>>
>>>>
>>>> -------------------------------------------------------
>>>> SF.Net email is sponsored by:
>>>> Tame your development challenges with Apache's Geronimo App Server.
>>>> Download it for free - -and be entered to win a 42" plasma tv or your
>> very
>>>> own Sony(tm)PSP. Click here to play:
>> http://sourceforge.net/geronimo.php
>>>> _______________________________________________
>>>> openMosix-devel mailing list
>>>> openMosix-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
>>>> https://lists.sourceforge.net/lists/listinfo/openmosix-devel
>>>>
>>>
>>
>>
>


-------------------------------------------------------
SF.Net email is sponsored by:
Tame your development challenges with Apache's Geronimo App Server. 
Download it for free - -and be entered to win a 42" plasma tv or your very
own Sony(tm)PSP.  Click here to play: http://sourceforge.net/geronimo.php