Hello, Am 15.08.2016 um 15:26 schrieb Philipp Hahn: > this Sunday one of our virtual servers running linux-4.1.16 inside > OpenStack using qemu "crashed" while doing a backup using rsync to a > slow NFS server.
This happened again last weekend, with the same stack trace: >> Call Trace: >> <IRQ> [<ffffffff81597807>] ? dump_stack+0x40/0x50 >> [<ffffffff8116b6e9>] ? warn_alloc_failed+0xf9/0x150 >> [<ffffffff8116ee7a>] ? __alloc_pages_nodemask+0x65a/0x9d0 >> [<ffffffff811b3024>] ? alloc_pages_current+0xa4/0x120 >> [<ffffffff81481d77>] ? skb_page_frag_refill+0xb7/0xe0 >> [<ffffffffa002d14b>] ? try_fill_recv+0x31b/0x610 [virtio_net] >> [<ffffffffa002db10>] ? virtnet_receive+0x580/0x890 [virtio_net] >> [<ffffffffa002de46>] ? virtnet_poll+0x26/0x90 [virtio_net] >> [<ffffffff81499629>] ? net_rx_action+0x159/0x330 >> [<ffffffff8107aace>] ? __do_softirq+0xde/0x260 >> [<ffffffff8107ae95>] ? irq_exit+0x95/0xa0 >> [<ffffffff815a0b74>] ? do_IRQ+0x64/0x110 >> [<ffffffff8159e9ee>] ? common_interrupt+0x6e/0x6e >> <EOI> [<ffffffff81020a70>] ? mwait_idle+0x150/0x150 >> [<ffffffff8105e192>] ? native_safe_halt+0x2/0x10 >> [<ffffffff81020a8c>] ? default_idle+0x1c/0xb0 >> [<ffffffff810b67f4>] ? cpu_startup_entry+0x314/0x3e0 >> [<ffffffff8159db87>] ? _raw_spin_unlock_irqrestore+0x17/0x50 >> [<ffffffff8104de55>] ? start_secondary+0x185/0x1b0 > What I don't know is if the network problem was the cause or the > consequence. Because of that I want to understand why the follwoing > order=0 allocation failed: What I still don't understand is how an "order=0" allocation can fail? >> Node 0 DMA: 1*4kB (U) 0*8kB 0*16kB 1*32kB (U) 2*64kB (U) 1*128kB (U) 1*256kB >> (U) 0*512kB 1*1024kB (U) 1*2048kB (R) 3*4096kB (EM) = 15908kB >> Node 0 DMA32: 4701*4kB (UM) 0*8kB 9*16kB (R) 0*32kB 1*64kB (R) 0*128kB >> 0*256kB 1*512kB (R) 0*1024kB 0*2048kB 0*4096kB = 19524kB >> Node 0 Normal: 352*4kB (UM) 5*8kB (UM) 2*16kB (R) 0*32kB 1*64kB (R) 1*128kB >> (R) 0*256kB 0*512kB 1*1024kB (R) 0*2048kB 0*4096kB = 2696kB >> Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 >> hugepages_size=2048kB In every zone there are plenty of free pages, so why doesn't allocation 4 KiB work? I looked at the source code, dis-assembly, similar reports, but now I'm lost. Can someone give me a hint where to look next please? Thank you in advance. Philipp Hahn