Re: ZONE_NORMAL memory exhausted by 4000 TCP sockets
From: Zhao Xiaoming
Date: Mon Nov 06 2006 - 05:16:19 EST
2006/11/6, Eric Dumazet <dada1@xxxxxxxxxxxxx>:
On Monday 06 November 2006 09:59, Zhao Xiaoming wrote:
> Thank you again for your help. To have more detailed statistic data, I
> did another round of test and gathered some data. I give the overall
> description here and detailed /proc/net/sockstat, /proc/meminfo,
> /proc/slabinfo and /proc/buddyinfo follows.
> =====================================================
> slab mem cost tcp mem pages lowmem
> free with traffic: 254668KB 34693
> 38772KB
> without traffic: 104080KB 1
> 702652KB
> =====================================================
Thank you for detailed infos.
It appears you have an extensive use of threads (about 10000), since :
> task_struct 10095 10095 1360 3 1 : tunables 24 12
> 8 : slabdata 3365 3365 0
Each thread has a kernel stack, 8KB (ie 2 pages, order-1 allocation), plus a
user vma
> vm_area_struct 21346 21504 92 42 1 : tunables 120 60
> 8 : slabdata 512 512 0
Most likely you dont need that much threads. A program with fewer threads will
perform better and use less ram.
Thanks for the comments. I known the threads may cost many memory.
However, I already excluded them from the statistics. The 'after test'
info was gotten while the 10000 threads running but no traffics
relayed. You may look at the meminfo of 'after test', there is still
104080 kB slab memory which should already included the thread kernel
memory cost (8K*10000=80MB). I know 10000 threads are not necessary
and just use the simple logic to do some test.
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