Re: 2.5.70-mm1 Strangeness

[Bongani Hlope (bonganilinux@mweb.co.za)]

On Thu, 29 May 2003 17:51:35 -0700
Andrew Morton <akpm@xxxxxxxxx> wrote:

> "David S. Miller" <davem@xxxxxxxxxx> wrote:
> >
> >    From: Andrew Morton <akpm@xxxxxxxxx>
> >    Date: Thu, 29 May 2003 13:55:41 -0700
> > 
> >    The ip_dst_cache seems unreasonably large.  Unless your desktop is a
> >    backbone router or something.
> > 
> > Lots of DST entries can result on any machine actually.  We create one
> > per source address, not just per destination address.  So if you talk
> > to a lot of sites, or lots of sites talk to you, you'll get a lot of
> > DST entries.
> > 
> > Regardless, 80MB _IS_ excessive.  That's nearly 400,000 entries.
> > It definitely indicates there is a leak somewhere.
> > 
> > Although it say:
> > 
> > ip_dst_cache       19470  19470   4096    1    1
> > 
> > Which is 19470 active objects right?
> 
> Yes, 19470 entries.  But note that each entry is 4096 bytes.
> 
> Something seems to have gone and bumped the object size from 240 bytes up
> to 4096.  This is actually what I want CONFIG_DEBUG_PAGEALLOC to do, but I
> don't think it does it yet.  
> 
> Bongani, if you have CONFIG_DEBUG_PAGEALLOC enabled then please try turning
> it off.  And maybe Manfred can throw some light on what slab has done
> there.
> 

Turning off CONFIG_DEBUG_PAGEALLOC helped, everything is running smoothly
cat /proc/sys/net/ipv4/route/max_size gave me 65536

The slabs were reclaimed before the PC died. I had a script that checked /proc/slabinfo
every 10 seconds and dup it to a file. The last output was: (for the slabs you asked me to watch)

ip_dst_cache          61     61   4096    1    1
! tunables            24   12    0
! slabdata            61     61      0
! globalstat      342536  53783 340902 2351    0   25   25
! cpustat   0       2231 406871 314930  28356

ext3_inode_cache    4331   4331   4096    1    1
! tunables            24   12    0
! slabdata          4331   4331      0
! globalstat       34388  26451 33205  580    0   25   25
! cpustat   0       2459  33332  28998   2462


dentry_cache       11016  11016   4096    1    1
! tunables            24   12    0
! slabdata         11016  11016      0
! globalstat      109937  29529 94505  418    0   25   25
! cpustat   0     568369  96256 645381   8243

So it seems like CONFIG_DEBUG_PAGEALLOC was causing the problem.

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