We've got a new application that is receiving UDP multicast data using AF_PACKET and writing out the packets in a custom format to disk. The packet rates are bursty, but it seems to be roughly 100 Mbps on average for 1 minute periods. With this application running all day we get a lot of these messages: [1298269.103034] kswapd1: page allocation failure: order:2, mode:0x4020 [1298269.103038] Pid: 80, comm: kswapd1 Not tainted 3.4.9-2.rgm.fc16.x86_64 #1 [1298269.103040] Call Trace: [1298269.103041] <IRQ> [<ffffffff810db746>] warn_alloc_failed+0xf6/0x160 [1298269.103053] [<ffffffff813c767d>] ? skb_copy_bits+0x16d/0x2c0 [1298269.103058] [<ffffffff810e83a9>] ? wakeup_kswapd+0x69/0x160 [1298269.103060] [<ffffffff810df188>] __alloc_pages_nodemask+0x6e8/0x930 [1298269.103064] [<ffffffff81114316>] alloc_pages_current+0xb6/0x120 [1298269.103070] [<ffffffffa00c142b>] mlx4_en_alloc_frag+0x16b/0x1e0 [mlx4_en] [1298269.103073] [<ffffffffa00c18a0>] mlx4_en_complete_rx_desc+0x120/0x1d0 [mlx4_en] [1298269.103076] [<ffffffffa00c27d4>] mlx4_en_process_rx_cq+0x584/0x700 [mlx4_en] [1298269.103079] [<ffffffffa00c29ef>] mlx4_en_poll_rx_cq+0x3f/0x80 [mlx4_en] [1298269.103083] [<ffffffff813d6569>] net_rx_action+0x119/0x210 [1298269.103086] [<ffffffff8103c690>] __do_softirq+0xb0/0x220 [1298269.103090] [<ffffffff8109911d>] ? handle_irq_event+0x4d/0x70 [1298269.103095] [<ffffffff8148e30c>] call_softirq+0x1c/0x30 [1298269.103100] [<ffffffff81003ef5>] do_softirq+0x55/0x90 [1298269.103101] [<ffffffff8103ca65>] irq_exit+0x75/0x80 [1298269.103103] [<ffffffff8148e853>] do_IRQ+0x63/0xe0 [1298269.103107] [<ffffffff81485667>] common_interrupt+0x67/0x67 [1298269.103108] <EOI> [<ffffffff8148523f>] ? _raw_spin_unlock_irqrestore+0xf/0x20 [1298269.103113] [<ffffffff811184b1>] compaction_alloc+0x361/0x3f0 [1298269.103115] [<ffffffff810e29b7>] ? pagevec_lru_move_fn+0xd7/0xf0 [1298269.103118] [<ffffffff81123d19>] migrate_pages+0xa9/0x470 [1298269.103120] [<ffffffff81118150>] ? perf_trace_mm_compaction_migratepages+0xd0/0xd0 [1298269.103122] [<ffffffff81118abb>] compact_zone+0x4cb/0x910 [1298269.103124] [<ffffffff8111904b>] __compact_pgdat+0x14b/0x190 [1298269.103125] [<ffffffff8111931d>] compact_pgdat+0x2d/0x30 [1298269.103129] [<ffffffff810f32b9>] ? fragmentation_index+0x19/0x70 [1298269.103131] [<ffffffff810eb15f>] balance_pgdat+0x6ef/0x710 [1298269.103133] [<ffffffff810eb2ca>] kswapd+0x14a/0x390 [1298269.103136] [<ffffffff810567c0>] ? add_wait_queue+0x60/0x60 [1298269.103138] [<ffffffff810eb180>] ? balance_pgdat+0x710/0x710 [1298269.103140] [<ffffffff81055e93>] kthread+0x93/0xa0 [1298269.103142] [<ffffffff8148e214>] kernel_thread_helper+0x4/0x10 [1298269.103144] [<ffffffff81055e00>] ? kthread_worker_fn+0x140/0x140 [1298269.103146] [<ffffffff8148e210>] ? gs_change+0xb/0xb The kernel is based on a Fedora 16 kernel and actually has the 3.4.10 patches applied. I can easily test patches or different kernels. I'm mostly wondering if there is anything that can be done about these failures? It appears that these failures have to do with handling fragmented IP frames, but the majority of the packets this machines should not be fragmented (there are probably some that are). >From a memory management point of view the system has 48GB of RAM, and typically 44GB of that is page cache. The dirty pages seem to hover around 5-6MB and the filesystem/disks don't seem to have any problems keeping up with writing out the data. -- Shawn -- --------------------------------------------------------------- This email, along with any attachments, is confidential. If you believe you received this message in error, please contact the sender immediately and delete all copies of the message. Thank you. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>