Re: Memory usage per memory zone

[Wu Fengguang]

On Thu, Mar 12, 2009 at 10:17:44AM +0200, jack marrow wrote:
> 2009/3/12 Wu Fengguang <fengguang.wu@xxxxxxxxx>:
> > On Thu, Mar 12, 2009 at 10:04:17AM +0200, jack marrow wrote:
> >> 2009/3/12 Wu Fengguang <fengguang.wu@xxxxxxxxx>:
> >> > On Thu, Mar 12, 2009 at 09:53:27AM +0200, jack marrow wrote:
> >> >> > Can you paste /proc/vmstat, /proc/meminfo, /proc/zoneinfo and
> >> >> > /proc/slabinfo? Thank you.
> >> >>
> >> >> Sure, but I don't know if it will help.
> >> >>
> >> >> The oom info was from in the night, the rest is from now. I have no zoneinfo.
> >> >>
> >> >> http://pastebin.com/m67409bc0
> >> >
> >> > Thank you! So you are running a pretty old kernel?
> >> >
> >>
> >> Yes. Kernel.2.6.9-78.
> >>
> >> Added more output from the other oom kills here:
> >> Âhttp://pastebin.com/m76fc473d
> >>
> >> If I could just find a way to find out what is using up all the memory
> >> in a zone I could go away happy :)
> >
> > But the highmem zone wont help you much, since you have a large 900M
> > normal zone and a tiny 100M highmem zone ;)
> >
> > The cached files seem to be the memory killer:
> 
> I ran an echo 3 > drop_caches yesterday, I was hoping to come in and
> find no oom kill. Oh well :)

Can you paste the /proc/meminfo after doing 'echo 3 > drop_caches'?

> I thought the kernel dropped caches if a program needs the ram?

Sure, but something is unreclaimable... Maybe some process is taking a
lot of shared memory(shm)? What's the output of `lsof`?

> >
> > MemTotal: Â Â Â1034496 kB
> > MemFree: Â Â Â Â 95600 kB
> > Buffers: Â Â Â Â 49916 kB
> > Cached: Â Â Â Â 761544 kB
> > SwapCached: Â Â Â Â Â0 kB
> > Active: Â Â Â Â Â80484 kB
> > Inactive: Â Â Â 749960 kB
> > HighTotal: Â Â Â131008 kB
> > HighFree: Â Â Â Â68480 kB
> > LowTotal: Â Â Â 903488 kB
> > LowFree: Â Â Â Â 27120 kB
> > SwapTotal: Â Â 2040212 kB
> > SwapFree: Â Â Â2039780 kB
> > Dirty: Â Â Â Â Â Â Â 4 kB
> > Writeback: Â Â Â Â Â 0 kB
> > Mapped: Â Â Â Â Â32636 kB
> > Slab: Â Â Â Â Â Â93856 kB
> > CommitLimit: Â 2557460 kB
> > Committed_AS: Â 129980 kB
> > PageTables: Â Â Â 1800 kB
> > VmallocTotal: Â 106488 kB
> > VmallocUsed: Â Â Â3372 kB
> > VmallocChunk: Â 102616 kB
> > HugePages_Total: Â Â 0
> > HugePages_Free: Â Â Â0
> > Hugepagesize: Â Â 2048 kB
> >
> > Is upgrading the kernel an option for you?
> 
> No :(
> 
> I think shoving some more ram in the box is the best doable option.
> Would this help here?

There have been huge amounts of change sets in mm area since 2.6.9...

> To do that I need to say "look at how much cache we are using for
> files, that cache is in the high mem zone (look here) so let's put
> some more ram in". Does the cache always live in the high mem zone?

Both highmem and normal zones will be used for caches.

Thanks,
Fengguang

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