Re: [Bug 12832] New: kernel leaks a lot of memory

[Wu Fengguang <fengguang.wu@intel.com>]

Hi Pierre,

On Sat, Mar 07, 2009 at 10:00:55PM +0100, Pierre Ossman wrote:
> On Sat, 7 Mar 2009 12:24:52 -0800
> Andrew Morton <akpm@linux-foundation.org> wrote:
> 
> > 
> > hm, not a lot to go on there.
> > 
> > We have quite a lot of instrumentation for memory consumption - were
> > you able to work out where it went by comparing /proc/meminfo,
> > /proc/slabinfo, `echo m > /proc/sysrq-trigger', etc?
> > 
> 
> The redhat entry contains all the info, and I've compared meminfo and
> slabinfo without finding anything even close to the chunks of lost
> memory.

The "free" pages in sysrq mem-info report should be equal to "MemFree"
in /proc/meminfo. So I'd expect meminfo numbers to be different in
.26/.27 as well.

Maybe the memory is taken by some user space program, so it would be
helpful to know the numbers in /proc/meminfo, /proc/vmstat and
/proc/zoneinfo.

> I've attached the sysrq memory stats from 2.6.26 and 2.6.27. The only
> difference though is in the reported free pages

The "free" entries in mem-info:

                     2.6.26     2.6.27
--------------------------------------
   free:             103730      62265 (pages)
  Node 0 DMA free:  10292kB     9448kB
  Node 0 DMA32 free:404628kB  239612kB

So there are 160MB less free pages in .27. Are you sure that initrd is
freed after booting?

Thanks,
Fengguang

> I'm not very familiar with all the instrumentation, so pointers are
> very welcome.
> 
> > Is the memory missing on initial boot up, or does it take some time for
> > the problem to become evident?
> > 
> 
> Initial boot as far as I can tell.
> 
> 
> Rgds
> -- 
>      -- Pierre Ossman
> 
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> Linux builder.drzeus.cx 2.6.26.6-79.fc9.x86_64 #1 SMP Fri Oct 17 14:20:33 EDT 2008 x86_64 x86_64 x86_64 GNU/Linux
> SysRq : Show Memory
> Mem-info:
> Node 0 DMA per-cpu:
> CPU    0: hi:    0, btch:   1 usd:   0
> Node 0 DMA32 per-cpu:
> CPU    0: hi:  186, btch:  31 usd: 115
> Active:8937 inactive:6285 dirty:48 writeback:0 unstable:0
>  free:103730 slab:5612 mapped:2148 pagetables:817 bounce:0
> Node 0 DMA free:10292kB min:48kB low:60kB high:72kB active:0kB inactive:0kB present:8908kB pages_scanned:0 all_unreclaimable? no
> lowmem_reserve[]: 0 489 489 489
> Node 0 DMA32 free:404628kB min:2804kB low:3504kB high:4204kB active:35748kB inactive:25140kB present:500896kB pages_scanned:0 all_unreclaimable? no
> lowmem_reserve[]: 0 0 0 0
> Node 0 DMA: 3*4kB 5*8kB 4*16kB 4*32kB 3*64kB 3*128kB 3*256kB 3*512kB 3*1024kB 2*2048kB 0*4096kB = 10292kB
> Node 0 DMA32: 3*4kB 5*8kB 2*16kB 2*32kB 2*64kB 1*128kB 3*256kB 2*512kB 3*1024kB 3*2048kB 96*4096kB = 404628kB
> 9730 total pagecache pages
> Swap cache: add 0, delete 0, find 0/0
> Free swap  = 524280kB
> Total swap = 524280kB
> 131056 pages of RAM
> 3772 reserved pages
> 7750 pages shared
> 0 pages swap cached
> 

> Linux builder.drzeus.cx 2.6.27.4-19.fc9.x86_64 #1 SMP Thu Oct 30 19:30:01 EDT 2008 x86_64 x86_64 x86_64 GNU/Linux
> SysRq : Show Memory
> Mem-Info:
> Node 0 DMA per-cpu:
> CPU    0: hi:    0, btch:   1 usd:   0
> Node 0 DMA32 per-cpu:
> CPU    0: hi:  186, btch:  31 usd:  86
> Active:8879 inactive:6265 dirty:8 writeback:0 unstable:0
>  free:62265 slab:5543 mapped:2154 pagetables:821 bounce:0
> Node 0 DMA free:9448kB min:40kB low:48kB high:60kB active:0kB inactive:0kB present:7804kB pages_scanned:0 all_unreclaimable? no
> lowmem_reserve[]: 0 489 489 489
> Node 0 DMA32 free:239612kB min:2808kB low:3508kB high:4212kB active:35516kB inactive:25060kB present:500896kB pages_scanned:0 all_unreclaimable? no
> lowmem_reserve[]: 0 0 0 0
> Node 0 DMA: 4*4kB 3*8kB 2*16kB 5*32kB 4*64kB 2*128kB 2*256kB 2*512kB 3*1024kB 2*2048kB 0*4096kB = 9448kB
> Node 0 DMA32: 1*4kB 7*8kB 6*16kB 1*32kB 1*64kB 4*128kB 3*256kB 3*512kB 1*1024kB 3*2048kB 56*4096kB = 239612kB
> 9692 total pagecache pages
> 0 pages in swap cache
> Swap cache stats: add 0, delete 0, find 0/0
> Free swap  = 524280kB
> Total swap = 524280kB
> 131056 pages RAM
> 4046 pages reserved
> 7770 pages shared
> 61196 pages non-shared
> 



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