Re: 2.6.20-rc5: cp 18gb 18gb.2 = OOM killer, reproducible just like 2.16.19.2

Justin Piszcz
2007-01-25T00:58:47Z

On Thu, 25 Jan 2007, Pavel Machek wrote:

> Hi!
>
> > > Is it highmem-related? Can you try it with mem=256M?
> >
> > Bad idea, the kernel crashes & burns when I use mem=256, I had to boot
> > 2.6.20-rc5-6 single to get back into my machine, very nasty. Remember I
> > use an onboard graphics controller that has 128MB of RAM allocated to it
> > and I believe the ICH8 chipset also uses some memory, in any event mem=256
> > causes the machine to lockup before it can even get to the boot/init
> > processes, the two leds on the keyboard were blinking, caps lock and
> > scroll lock and I saw no console at all!
>
> Okay, so try mem=700M or disable CONFIG_HIGHMEM or something.
> Pavel
> --
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> (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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Looks like you may be onto something Pavel, has not invoked the OOM killer
yet using mem=700M, I see the swap increasing and the speed of the copy is
only 14-15MB/s, when mem= is off (giving me all memory w/preempt) I get
45-65MB/s.

With append="mem=700M", seen below:

top - 19:38:46 up 1 min, 3 users, load average: 1.24, 0.38, 0.13
Tasks: 172 total, 1 running, 171 sleeping, 0 stopped, 0 zombie
Cpu(s): 10.6%us, 4.6%sy, 1.3%ni, 69.6%id, 13.9%wa, 0.0%hi, 0.1%si, 0.0%st
Mem: 705512k total, 699268k used, 6244k free, 12k buffers
Swap: 2200760k total, 18520k used, 2182240k free, 34968k cached

(with mem=700M):
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
2 0 40276 7456 12 23184 0 0 13196 14904 1204 4756 1 2 50 47
0 2 40276 6156 12 24264 0 0 20096 18352 1293 6400 1 4 49 46
0 2 40276 6264 12 24264 0 0 15504 17836 1219 5202 0 2 50 48
0 2 40276 6144 12 24376 0 0 14348 14453 1190 4815 0 3 49 48
0 2 40276 6156 12 24504 0 0 11396 12724 1169 3724 1 2 50 48
0 1 40276 7532 12 23272 0 0 11412 13121 1183 4017 0 2 50 48
0 1 40276 7944 12 22644 0 0 19084 19144 1234 6548 0 4 50 46

Almost there, looks like its going to make it.
-rw-r--r-- 1 user group 18630127104 2007-01-21 12:41 18gb
-rw-r--r-- 1 user group 15399329792 2007-01-24 19:55 18gb.copy

Hrmm, with preempt off it works and with preempt ON and mem=700M it works.
I guess I will run with preempt off as I'd prefer to have the memory
available-- and tolerate the large lag bursts w/ no preemption.

Yup it worked.

-rw-r--r-- 1 user group 18630127104 2007-01-21 12:41 18gb
-rw-r--r-- 1 user group 18630127104 2007-01-21 12:41 18gb.copy

Justin.