Re: VM breakdown, 2.4.0 family

David Ford (david@linux.com)
Sat, 27 Jan 2001 23:21:08 +0000


I have Marcelo's patch. It isn't applicable because I am purposely not enabling any
swap. The problem is the system gets down to about 7 megs of buffers free and within
three seconds has become functionally dead. Zero response on any user input/output
device save the magic key.

The system will then grind the harddrive solid for about 25-30 minutes then
everything will go silent.

The brokenness is that the OOM code never activates.

-d

Ed Tomlinson wrote:

> David Ford Wrote:
>
> >Since the testN series and up through ac12, I experience total loss of
> >control when memory is nearly exhausted.
> >
> >I start with 256M and eat it up with programs until there is only about
> >7 megs left, no swap. From that point all user processes stall and the
> >disk begins to grind nonstop. It will continue to grind for about 25-30
> >minutes until it goes completely silent. No processes get killed, no VM
> >messages are emitted.
> >
> >The only recourse is the magic key. If I reboot before the disk goes
> >silent I can cleanly kill X with sysrq-E and restart.
> >
> >If I wait until it goes silent, all is lost. I have to sysrq-SUB.
>
> You might want to try:
>
> http://bazar.conectiva.com.br/~marcelo/patches/v2.4/2.4.1pre10/bg_page_aging.patch
>
> or
>
> ftp://ftp.cam.org/users/tomlins/pte_aging_limit_swaps.diff
>
> The first patch from Marcelo fixes a problem with aging the wrong pages. The
> second patch is sort of a 'best of Marcelo' patch. It contains the aging fix
> and adds conditional bg pte aging (if with activate fast than we age
> down...). It also has code to trottle swapouts when under preasure - it only
> swaps out as much as we need now.
>
> I have fives days of uptime with it here (on test9 and test10).
>
> Feedback Welcome,
>
> Ed Tomlinson <tomlins@cam.org>

--
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  The good thing about standards is that there are so many to choose from. Andrew S. Tanenbaum

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