Re: VM breakdown, 2.4.0 family

[David Ford]

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 <[e-mail]>

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