Re: [PATCH 1/1] mips: fault.c: Port OOM changes to do_page_fault

[Kautuk Consul <consul.kautuk@xxxxxxxxx>]

>
> Without these changes, my MIPS board encounters many hang and livelock
> scenarios.
> After applying this patch, OOM feature performance improves according to
> my testing.
>

Just to clarify the hang scenario I am talking about, the test case I
used to reproduce
this problem is attached to this email.
Running this a few times hangs my console and then even Ctrl-C signals
do not get handled
and I also do not get back the command prompt.

After applying this patch things seem to improve, but there are still
some hangs which I
encounter which I am further trying to debug.

However, since the generic part of the kernel(mm/filemap.c) now
supports killable and
retryable page fault handling, I thought that this change would be
valid for MIPS too.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <unistd.h>

#define ALLOC_BYTE 512*1024
#define COUNT 50

void *alloc_function_one( void *ptr );
void *alloc_function_two( void *ptr );
void *alloc_function_three( void *ptr );
void *alloc_function_four( void *ptr );
void *alloc_function_five( void *ptr );
void *enable_function( void *ptr );


int main(int argc, char *argv[])
{
	pthread_t thread1, thread2, thread3, thread4, thread5;
	char *message1 = "Thread 1";
	char *message2 = "Thread 2";
	char *message3 = "Thread 3";
	char *message4 = "Thread 4";
	char *message5 = "Thread 5";
	int iret1 = -1;
	int iret2 = -1;
	int iret3 = -1;
	int iret4 = -1;
	int iret5 = -1;
	fork();
	iret1 = pthread_create( &thread1, NULL, alloc_function_one, (void*) message1);
	iret2 = pthread_create( &thread2, NULL, alloc_function_two, (void*) message2);
	iret2 = pthread_create( &thread3, NULL, alloc_function_three, (void*) message2);
	iret2 = pthread_create( &thread4, NULL, alloc_function_four, (void*) message2);
	iret2 = pthread_create( &thread5, NULL, alloc_function_five, (void*) message2);

	pthread_join( thread1, NULL);
	pthread_join( thread2, NULL);
	pthread_join( thread3, NULL);
	pthread_join( thread4, NULL);
	pthread_join( thread5, NULL);

	printf("Thread 1 returns: %d\n",iret1);
	printf("Thread 2 returns: %d\n",iret2);
	printf("Thread 3 returns: %d\n",iret3);
	printf("Thread 4 returns: %d\n",iret4);
	printf("Thread 5 returns: %d\n",iret5);
	exit(0);
}

void *alloc_function_two( void *ptr )
{
	char *message;
	message = (char *) ptr;
	void *myblock[COUNT];
	int i= 0,j=0;
	int freed=0;
	printf("message_alloc  \n");
	while(1)
	{
		memset(myblock,0,sizeof(myblock));
		printf("message_alloc %s \n",message);
		for(i=0;i< COUNT ;i++)
		{
			myblock[i] = (void *) malloc(ALLOC_BYTE);
			memset(myblock[i],1, ALLOC_BYTE);
		}
	}
}


void *alloc_function_one( void *ptr )
{
	char *message;
	message = (char *) ptr;
	void *myblock[COUNT];
	int i= 0,j=0;
	int freed=0;
	printf("message_alloc  \n");
	while(1)
	{
		memset(myblock,0,sizeof(myblock));
		printf("message_alloc %s \n",message);
		for(i=0;i< COUNT ;i++)
		{
			myblock[i] = (void *) malloc(ALLOC_BYTE);
			memset(myblock[i],1, ALLOC_BYTE);
		}
	}
}

void *alloc_function_three( void *ptr )
{
       char *message;
        message = (char *) ptr;
        void *myblock[COUNT];
        int i= 0,j=0;
        int freed=0;
        printf("message_alloc  \n");
        while(1)
        {
                memset(myblock,0,sizeof(myblock));
                printf("message_alloc %s \n",message);
                for(i=0;i< COUNT ;i++)
                {
                        myblock[i] = (void *) malloc(ALLOC_BYTE);
                        memset(myblock[i],1, ALLOC_BYTE);
                }
        }
}
void *alloc_function_four( void *ptr )
{
       char *message;
        message = (char *) ptr;
        void *myblock[COUNT];
        int i= 0,j=0;
        int freed=0;
        printf("message_alloc  \n");
        while(1)
        {
                memset(myblock,0,sizeof(myblock));
                printf("message_alloc %s \n",message);
                for(i=0;i< COUNT ;i++)
                {
                        myblock[i] = (void *) malloc(ALLOC_BYTE);
                        memset(myblock[i],1, ALLOC_BYTE);
                }
        }
}
void *alloc_function_five( void *ptr )
{
       char *message;
        message = (char *) ptr;
        void *myblock[COUNT];
        int i= 0,j=0;
        int freed=0;
        printf("message_alloc  \n");
        while(1)
        {
                memset(myblock,0,sizeof(myblock));
                printf("message_alloc %s \n",message);
                for(i=0;i< COUNT ;i++)
                {
                        myblock[i] = (void *) malloc(ALLOC_BYTE);
                        memset(myblock[i],1, ALLOC_BYTE);
                }
        }
}