> -----Original Message----- > From: linux-scsi-owner@xxxxxxxxxxxxxxx [mailto:linux-scsi- > owner@xxxxxxxxxxxxxxx] On Behalf Of Alex Thorlton > Sent: Tuesday, 02 December, 2014 3:58 PM ... > We've recently upgraded our big machine up to 6144 cores, and we're > shaking out a number of bugs related to booting at that large core > count. Last night I tripped a warning from the lpfc driver that appears > to be related to a kzalloc that uses the number of cores as part of it's > size calculation. Here's the backtrace from the warning: ... > For a little bit more information on exactly what's going wrong, we're > tripping the warning from lpfc_pci_probe_one_s4 (as you can see from the > trace). That function calls down to lpfc_sli4_driver_resource_setup, > which contains the failing kzalloc here: > > phba->sli4_hba.cpu_map = kzalloc((sizeof(struct lpfc_vector_map_info) * > phba->sli4_hba.num_present_cpu), > GFP_KERNEL); > > As mentioned, it looks like we're multiplying the number available cpus > by that struct size to get an allocation size, which ends up being > greater than KMALLOC_MAX_SIZE. > > Does anyone have any ideas on what could be done to break that > allocation up into smaller pieces, or to make it in a different way so > that we avoid this warning? > > Any help is greatly appreciated. Thanks! > That structure includes an NR_CPU-based maskbits field, which is probably too big. include/cpumask.h: typedef struct cpumask { DECLARE_BITMAP(bits, NR_CPUS); } cpumask_t; drivers/scsi/lpfc/lpfc_sli4.h: struct lpfc_vector_map_info { uint16_t phys_id; uint16_t core_id; uint16_t irq; uint16_t channel_id; struct cpumask maskbits; }; maskbits appears to only be used for setting IRQ affinity hints in drivers/scsi/lpfc_init.c: for (idx = 0; idx < vectors; idx++) { cpup = phba->sli4_hba.cpu_map; cpu = lpfc_find_next_cpu(phba, phys_id); ... mask = &cpup->maskbits; cpumask_clear(mask); cpumask_set_cpu(cpu, mask); i = irq_set_affinity_hint(phba->sli4_hba.msix_entries[idx]. vector, mask); In similar code, mpt3sas and lockless hpsa just call get_cpu_mask() inside the loop: cpu = cpumask_first(cpu_online_mask); for (i = 0; i < h->msix_vector; i++) { rc = irq_set_affinity_hint(h->intr[i], get_cpu_mask(cpu)); cpu = cpumask_next(cpu, cpu_online_mask); } get_cpu_mask() uses the global cpu_bit_bitmap array, which is declared in kernel/cpu.c: extern const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)]; That approach should work for lpfc. --- Rob Elliott HP Server Storage -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
