linux out of memory

23:38:22 relay(kern.warning) apache2 invoked oom-killer: gfp_mask=0x201da, order=0, oomkilladj=0
23:38:22 relay(kern.warning) Pid: 17609, comm: apache2 Not tainted 2.6.31-gentoo-r6-2p3-aic #2
23:38:22 relay(kern.warning) Call Trace:
..skip..
23:38:28 relay(kern.info) Mem-Info:
23:38:31 relay(kern.warning) DMA per-cpu:
23:38:34 relay(kern.warning) CPU 0: hi: 0, btch: 1 usd: 0
23:38:34 relay(kern.warning) CPU 1: hi: 0, btch: 1 usd: 0
23:38:34 relay(kern.warning) Normal per-cpu:
23:38:34 relay(kern.warning) CPU 0: hi: 186, btch: 31 usd: 115
23:38:34 relay(kern.warning) CPU 1: hi: 186, btch: 31 usd: 155
23:38:34 relay(kern.warning) Active_anon:57086 active_file:544 inactive_anon:57115
23:38:34 relay(kern.warning) inactive_file:519 unevictable:0 dirty:0 writeback:0 unstable:0
23:39:02 relay(kern.warning) free:1237 slab:6409 mapped:7 pagetables:2031 bounce:0
23:39:02 relay(kern.warning) DMA free:2040kB min:84kB low:104kB high:124kB active_anon:5528kB inactive_anon:5540kB active_file:52kB inactive_file:28kB unevictable:0kB present:15804kB pages_scanned:98 all_unreclaimable? no
23:39:02 relay(kern.warning) lowmem_reserve[]: 0 492 492 492
23:39:02 relay(kern.warning) Normal free:2908kB min:2792kB low:3488kB high:4188kB active_anon:222816kB inactive_anon:222920kB active_file:2124k inactive_file:2048kB unevictable:0kB present:503872kB pages_scanned:4834 all_unreclaimable? no
23:39:02 relay(kern.warning) lowmem_reserve[]: 0 0 0 0
23:39:02 relay(kern.warning) DMA: 252*4kB 134*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 2080kB
23:39:02 relay(kern.warning) Normal: 735*4kB 8*8kB 0*16kB 1*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 3036kB
23:39:02 relay(kern.warning) 8792 total pagecache pages
23:39:02 relay(kern.warning) 7722 pages in swap cache
23:39:02 relay(kern.warning) Swap cache stats: add 14666056, delete 14658334, find 106426948/108982422
23:39:02 relay(kern.warning) Free swap = 0kB
23:39:02 relay(kern.warning) Total swap = 250872kB
23:39:02 relay(kern.info) 131040 pages RAM
23:39:02 relay(kern.info) 0 pages HighMem
23:39:02 relay(kern.info) 2532 pages reserved
23:39:02 relay(kern.info) 66041 pages shared
23:39:02 relay(kern.info) 124469 pages non-shared
23:39:02 relay(kern.err) Out of memory: kill process 17870 (mysqld) score 72685 or a child
23:39:02 relay(kern.err) Killed process 17870 (mysqld)