php5 - page allocation failure

[506492.851877] php5: page allocation failure: order:1, mode:0x20
[506492.851963] Pid: 15231, comm: php5 Not tainted 3.0.4intel #1
[506492.852033] Call Trace:
[506492.852098]  <IRQ>  [<ffffffff810bcc33>] warn_alloc_failed+0xf3/0x170
[506492.852231]  [<ffffffff810427fd>] ? default_wake_function+0xd/0x10
[506492.852305]  [<ffffffff81066ab1>] ? autoremove_wake_function+0x11/0x40
[506492.852377]  [<ffffffff8103569e>] ? __wake_up+0x4e/0x70
[506492.852448]  [<ffffffff810bddd0>] __alloc_pages_nodemask+0x5b0/0x810
[506492.852520]  [<ffffffff810bddd0>] ? __alloc_pages_nodemask+0x5b0/0x810
[506492.852596]  [<ffffffff81515bc4>] ? nf_iterate+0x84/0xb0
[506492.852669]  [<ffffffff810f4492>] kmem_getpages+0x62/0x160
[506492.852739]  [<ffffffff810f4f17>] fallback_alloc+0x147/0x1e0
[506492.852740]  [<ffffffff810f4cfc>] ____cache_alloc_node+0x8c/0x160
[506492.852740]  [<ffffffff810f5793>] kmem_cache_alloc+0x193/0x1b0
[506492.852740]  [<ffffffff814e677e>] sk_prot_alloc+0x3e/0x170
[506492.852740]  [<ffffffff814e79ed>] sk_clone+0x1d/0x2d0
[506492.852740]  [<ffffffff81527243>] inet_csk_clone+0x13/0xb0
[506492.852740]  [<ffffffff8153fe55>] tcp_create_openreq_child+0x25/0x480
[506492.852740]  [<ffffffff8153e447>] tcp_v4_syn_recv_sock+0x47/0x230
[506492.852740]  [<ffffffff8153fccd>] tcp_check_req+0x2cd/0x430
[506492.852740]  [<ffffffff8153ef5a>] tcp_v4_do_rcv+0x1ca/0x2d0
[506492.852740]  [<ffffffff8153f6eb>] tcp_v4_rcv+0x68b/0x810
[506492.852740]  [<ffffffff8151cf95>] ip_local_deliver_finish+0xc5/0x190
[506492.852740]  [<ffffffff8151d0ed>] ip_local_deliver+0x8d/0xa0
[506492.852740]  [<ffffffff8151ca12>] ip_rcv_finish+0x172/0x340
[506492.852740]  [<ffffffff8151ce4b>] ip_rcv+0x26b/0x2f0
[506492.852740]  [<ffffffff814f2fb0>] __netif_receive_skb+0x280/0x480
[506492.852740]  [<ffffffff81054fcc>] ? run_timer_softirq+0x3c/0x320
[506492.852740]  [<ffffffff814f329e>] process_backlog+0xee/0x1e0
[506492.852740]  [<ffffffff814f960a>] net_rx_action+0x10a/0x2b0
[506492.852740]  [<ffffffff8104c3f0>] __do_softirq+0xd0/0x1c0
[506492.852740]  [<ffffffff815a490c>] call_softirq+0x1c/0x30
[506492.852740]  <EOI>  [<ffffffff81004795>] ? do_softirq+0x55/0x90
[506492.852740]  [<ffffffff8104cc31>] local_bh_enable_ip+0x91/0xa0
[506492.852740]  [<ffffffff815a2eb0>] _raw_spin_unlock_bh+0x10/0x20
[506492.852740]  [<ffffffff814e5be7>] release_sock+0x117/0x120
[506492.852740]  [<ffffffff8154e32d>] inet_stream_connect+0x6d/0x2f0
[506492.852740]  [<ffffffff81102260>] ? get_empty_filp+0x80/0x140
[506492.852740]  [<ffffffff814e1cec>] sys_connect+0x8c/0xe0
[506492.852740]  [<ffffffff810fe890>] ? fd_install+0x30/0x60
[506492.852740]  [<ffffffff81110760>] ? sys_fcntl+0x220/0x600
[506492.852740]  [<ffffffff815a37bb>] system_call_fastpath+0x16/0x1b