memory problem when using linuxppc-2.4.4 in mpc8260 board

memory problem when using linuxppc-2.4.4 in mpc8260 board

[shuaiye1999]

hi,all:

     I have a bad headache of the memory problem of mpc8260 board using
linuxppc-2.4.4, the ELDK version.we got 32M ram,after booting,it seems
have 21000 K free,but when we use the system,it seems have little
memory.I did a simple test about this,and use bdi2000+gdb get some
data.and feel lost about the infomation.Can anybody give some infomation
about it? thx a lot.

==>the simple program is used to test:

sleep1.c:

main()
{
        while(1)
                sleep(1);
}

==>call it 12 times:

bash-2.05#./sleep1 &
[12] 229

==>just now ,it jump into the break point:

Breakpoint 4, bad_page_fault (regs=0xc1cd3ab0, address=2104558664, sig=2104558456) at fault.c:224
224             if ((fixup = search_exception_table(regs->nip)) != 0) {

(gdb) bt
#0  bad_page_fault (regs=0xc1cd3ab0, address=2104558664, sig=2104558456) at fault.c:224
#1  0xc000c964 in do_page_fault (regs=0xc1cd3ab0, address=2104558664, error_code=536870912) at fault.c:185
#2  0xc0003de4 in ret_from_except () at init/main.c:858
#3  0xc00fbec4 in udp_data_ready (sk=0xc0254680, len=2104558664) at xprt.c:654
#4  0xc00e9624 in udp_queue_rcv_skb (sk=0xc0254680, skb=0xc025d620)
    at /home/xdhe/begin/linux-2.4/include/net/sock.h:1191
#5  0xc00e9aa8 in udp_rcv (skb=0xc025d620) at udp.c:908
#6  0xc00ca1c0 in ip_local_deliver (skb=0xc025d620) at ip_input.c:265
#7  0xc00ca618 in ip_rcv (skb=0xc025d620, dev=0x7d710448, pt=0xb) at ip_input.c:372
#8  0xc00c037c in net_rx_action (h=0xc1cd3ab0) at dev.c:1485
#9  0xc0016880 in do_softirq () at softirq.c:78
#10 0xc0003e0c in do_bottom_half_ret () at init/main.c:858
#11 0xc002180c in do_wp_page (mm=0xc0004de8, vma=0xc19a5f20, address=269104860, page_table=0xc1b7a28c, pte=
      {pte = 25297283}) at memory.c:953
#12 0xc002226c in handle_mm_fault (mm=0xc02e8220, vma=0xc19a5f20, address=269104860, write_access=33554432)
    at memory.c:1312
#13 0xc000c860 in do_page_fault (regs=0xc1cd3e90, address=269104860, error_code=167772160) at fault.c:149
#14 0xc0003de4 in ret_from_except () at init/main.c:858
#15 0x10019804 in ?? ()

best regards.

shuaiye

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Re: memory problem when using linuxppc-2.4.4 in mpc8260 board

[Wolfgang Denk]

Dear Shuaiye,

in message <1222072.1058347005274.JavaMail.postfix@mx49.mail.sohu.com> you wrote:
>
>      I have a bad headache of the memory problem of mpc8260 board using
> linuxppc-2.4.4, the ELDK version.we got 32M ram,after booting,it seems
> have 21000 K free,but when we use the system,it seems have little
> memory.I did a simple test about this,and use bdi2000+gdb get some

I assume you are uysing a ramdisk, right? How big  is  this  ramdisk?
Otherwise 21000 K free is not reasonable.


What makes you think you are running out of memory?

> data.and feel lost about the infomation.Can anybody give some infomation
> about it? thx a lot.

Which sort of data are you _trying_ to get in  the  first  place?  It
makes  little  sense  just  to  poke  around when you don;t know what
you're looking for...

> ==>the simple program is used to test:
>
> sleep1.c:
>
> main()
> {
>         while(1)
>                 sleep(1);
> }
>
> ==>call it 12 times:
>
> bash-2.05#./sleep1 &
> [12] 229
>
> ==>just now ,it jump into the break point:
>
> Breakpoint 4, bad_page_fault (regs=0xc1cd3ab0, address=2104558664, sig=2104558456) at fault.c:224
> 224             if ((fixup = search_exception_table(regs->nip)) != 0) {
>
> (gdb) bt
> #0  bad_page_fault (regs=0xc1cd3ab0, address=2104558664, sig=2104558456) at fault.c:224
> #1  0xc000c964 in do_page_fault (regs=0xc1cd3ab0, address=2104558664, error_code=536870912) at fault.c:185
> #2  0xc0003de4 in ret_from_except () at init/main.c:858
> #3  0xc00fbec4 in udp_data_ready (sk=0xc0254680, len=2104558664) at xprt.c:654
> #4  0xc00e9624 in udp_queue_rcv_skb (sk=0xc0254680, skb=0xc025d620)
...


I see no problem here. Linux implements  virtual  memory,  so  it  is
perfectly normal that page faults happen (and will be handled).


What exactly is your problem?

Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
A committee is a life form with six or more legs and no brain.
                              -- Lazarus Long, "Time Enough For Love"

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