Jan Stancek wrote: > > Jan, can you reproduce your problem with below patch applied? > > I took v4.5-rc1, applied your memalloc patch and then patch below. > > I have mixed results so far. First attempt hanged after ~15 minutes, > second is still running (for 12+ hours). > > The way it hanged is different from previous ones, I don't recall seeing > messages like these before: > SLUB: Unable to allocate memory on node -1 (gfp=0x2000000) > NMI watchdog: Watchdog detected hard LOCKUP on cpu 0 > > Full log from one that hanged: > http://jan.stancek.eu/tmp/oom_hangs/console.log.4-v4.5-rc1_and_wait_iff_congested_patch.txt > The first attempt's failure is not a OOM bug. It's a hard lockup due to flood of memory allocation failure messages which lasted for 10 seconds with IRQ disabled. The caller which requested these atomic allocation did not expect such situation. I think dma_active_cacheline can consider adding __GFP_NOWARN. Please consult lib/dma-debug.c maintainers. static RADIX_TREE(dma_active_cacheline, GFP_NOWAIT); ---------- int ata_scsi_queuecmd(struct Scsi_Host *shost, struct scsi_cmnd *cmd) { spin_lock_irqsave(ap->lock, irq_flags); /* Disable IRQ. */ __ata_scsi_queuecmd(cmd, dev) { ata_scsi_translate(dev, scmd, xlat_func) { ata_qc_issue(qc) { ata_sg_setup(qc) { dma_map_sg(ap->dev, qc->sg, qc->n_elem, qc->dma_dir) { debug_dma_map_sg(dev, sg, nents, ents, dir) { add_dma_entry(entry) { /* Iterate the loop for "ents" times. */ rc = active_cacheline_insert(entry); /* "SLUB: Unable to allocate memory" message */ if (rc == -ENOMEM) { pr_err("DMA-API: cacheline tracking ENOMEM, dma-debug disabled\n"); global_disable = true; } } } } } } } } spin_unlock_irqrestore(ap->lock, irq_flags); /* Enable IRQ */ } ---------- By the way, I think there is no need to print these error messages again after global_disable became true. ---------- [ 1053.123934] SLUB: Unable to allocate memory on node -1 (gfp=0x2000000) [ 1053.147529] DMA-API: cacheline tracking ENOMEM, dma-debug disabled [ 1053.796970] SLUB: Unable to allocate memory on node -1 (gfp=0x2000000) [ 1053.820563] DMA-API: cacheline tracking ENOMEM, dma-debug disabled [ 1054.469776] SLUB: Unable to allocate memory on node -1 (gfp=0x2000000) [ 1054.493371] DMA-API: cacheline tracking ENOMEM, dma-debug disabled [ 1055.142562] SLUB: Unable to allocate memory on node -1 (gfp=0x2000000) [ 1055.166156] DMA-API: cacheline tracking ENOMEM, dma-debug disabled [ 1055.815330] SLUB: Unable to allocate memory on node -1 (gfp=0x2000000) [ 1055.838924] DMA-API: cacheline tracking ENOMEM, dma-debug disabled [ 1056.495796] SLUB: Unable to allocate memory on node -1 (gfp=0x2000000) [ 1056.519400] DMA-API: cacheline tracking ENOMEM, dma-debug disabled [ 1057.168741] SLUB: Unable to allocate memory on node -1 (gfp=0x2000000) [ 1057.192333] DMA-API: cacheline tracking ENOMEM, dma-debug disabled [ 1057.841671] SLUB: Unable to allocate memory on node -1 (gfp=0x2000000) [ 1057.865264] DMA-API: cacheline tracking ENOMEM, dma-debug disabled [ 1058.514604] SLUB: Unable to allocate memory on node -1 (gfp=0x2000000) [ 1058.538200] DMA-API: cacheline tracking ENOMEM, dma-debug disabled [ 1059.187551] SLUB: Unable to allocate memory on node -1 (gfp=0x2000000) [ 1059.211142] DMA-API: cacheline tracking ENOMEM, dma-debug disabled [ 1059.860486] SLUB: Unable to allocate memory on node -1 (gfp=0x2000000) [ 1059.884080] DMA-API: cacheline tracking ENOMEM, dma-debug disabled [ 1060.533430] SLUB: Unable to allocate memory on node -1 (gfp=0x2000000) [ 1060.557023] DMA-API: cacheline tracking ENOMEM, dma-debug disabled [ 1061.206393] SLUB: Unable to allocate memory on node -1 (gfp=0x2000000) [ 1061.229984] DMA-API: cacheline tracking ENOMEM, dma-debug disabled [ 1061.879330] SLUB: Unable to allocate memory on node -1 (gfp=0x2000000) [ 1061.902924] DMA-API: cacheline tracking ENOMEM, dma-debug disabled [ 1062.552266] SLUB: Unable to allocate memory on node -1 (gfp=0x2000000) [ 1062.575857] DMA-API: cacheline tracking ENOMEM, dma-debug disabled [ 1063.219374] SLUB: Unable to allocate memory on node -1 (gfp=0x2000000) [ 1063.242967] DMA-API: cacheline tracking ENOMEM, dma-debug disabled [ 1063.892314] SLUB: Unable to allocate memory on node -1 (gfp=0x2000000) [ 1063.915908] DMA-API: cacheline tracking ENOMEM, dma-debug disabled ---------- -- 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>