On Tue, Oct 30, 2018 at 10:34 AM Lin, Xueqin <xueqin....@intel.com> wrote:
> Hi Lucero, > > > > No, we have reproduced multi-process issues(include symmetric_mp, > simple_mp, hotplug_mp, multi-process unit test… )on most of our servers. > > It is also strange that 1~2 servers don’t have the issue. > > > Yes, you are right. I could execute it but it was due to how this problem triggers. I think I can fix this and at the same time solving properly the initial issue without any limitation like that potential race condition I mentioned. I can give you a patch to try in a couple of hours. Thanks > Bind two NNT ports or FVL ports > > > > ./build/symmetric_mp -c 4 --proc-type=auto -- -p 3 --num-procs=4 > --proc-id=1 > > > > EAL: Detected 88 lcore(s) > > EAL: Detected 2 NUMA nodes > > EAL: Auto-detected process type: SECONDARY > > [New Thread 0x7ffff6eda700 (LWP 90103)] > > EAL: Multi-process socket /var/run/dpdk/rte/mp_socket_90099_2f1b553882b62 > > [New Thread 0x7ffff66d9700 (LWP 90104)] > > > > Thread 1 "symmetric_mp" received signal SIGSEGV, Segmentation fault. > > 0x00000000005566b5 in rte_fbarray_find_next_used () > > (gdb) bt > > #0 0x00000000005566b5 in rte_fbarray_find_next_used () > > #1 0x000000000054da9c in rte_eal_check_dma_mask () > > #2 0x0000000000572ae7 in pci_one_device_iommu_support_va () > > #3 0x0000000000573988 in rte_pci_get_iommu_class () > > #4 0x000000000054f743 in rte_bus_get_iommu_class () > > #5 0x000000000053c123 in rte_eal_init () > > #6 0x000000000046be2b in main () > > > > Best regards, > > Xueqin > > > > *From:* Alejandro Lucero [mailto:alejandro.luc...@netronome.com] > *Sent:* Tuesday, October 30, 2018 5:41 PM > *To:* Lin, Xueqin <xueqin....@intel.com> > *Cc:* Yao, Lei A <lei.a....@intel.com>; Thomas Monjalon < > tho...@monjalon.net>; dev <dev@dpdk.org>; Xu, Qian Q <qian.q...@intel.com>; > Burakov, Anatoly <anatoly.bura...@intel.com>; Yigit, Ferruh < > ferruh.yi...@intel.com>; Zhang, Qi Z <qi.z.zh...@intel.com> > *Subject:* Re: [dpdk-dev] [PATCH v3 0/6] use IOVAs check based on DMA mask > > > > > > On Tue, Oct 30, 2018 at 3:20 AM Lin, Xueqin <xueqin....@intel.com> wrote: > > Hi Lucero&Thomas, > > > > Find the patch can’t fix multi-process cases. > > > > Hi, > > > > I think it is not specifically about multiprocess but about hotplug with > multiprocess because I can execute the symmetric_mp successfully with a > secondary process. > > > > Working on this as a priority. > > > > Thanks. > > > > Steps: > > 1. Setup primary process successfully > > ./hotplug_mp --proc-type=auto > > > > 2. Fail to setup secondary process > > ./hotplug_mp --proc-type=auto > > EAL: Detected 88 lcore(s) > > EAL: Detected 2 NUMA nodes > > EAL: Auto-detected process type: SECONDARY > > EAL: Multi-process socket /var/run/dpdk/rte/mp_socket_147212_2bfe08ee88d23 > > Segmentation fault (core dumped) > > > > More information as below: > > Thread 1 "hotplug_mp" received signal SIGSEGV, Segmentation fault. > > 0x0000000000597cfb in find_next (arr=0x7ffff7ff20a4, start=0, used=true) > > at /root/dpdk/lib/librte_eal/common/eal_common_fbarray.c:264 > > 264 for (idx = first; idx < msk->n_masks; idx++) { > > #0 0x0000000000597cfb in find_next (arr=0x7ffff7ff20a4, start=0, > used=true) > > at /root/dpdk/lib/librte_eal/common/eal_common_fbarray.c:264 > > #1 0x0000000000598573 in fbarray_find (arr=0x7ffff7ff20a4, start=0, > next=true, > > used=true) at > /root/dpdk/lib/librte_eal/common/eal_common_fbarray.c:1001 > > #2 0x000000000059929b in rte_fbarray_find_next_used (arr=0x7ffff7ff20a4, > start=0) > > at /root/dpdk/lib/librte_eal/common/eal_common_fbarray.c:1018 > > #3 0x000000000058c877 in rte_memseg_walk_thread_unsafe (func=0x58c401 > <check_iova>, > > arg=0x7fffffffcc38) at > /root/dpdk/lib/librte_eal/common/eal_common_memory.c:589 > > #4 0x000000000058ce08 in rte_eal_check_dma_mask (maskbits=48 '0') > > at /root/dpdk/lib/librte_eal/common/eal_common_memory.c:465 > > #5 0x00000000005b96c4 in pci_one_device_iommu_support_va (dev=0x11b3d90) > > at /root/dpdk/drivers/bus/pci/linux/pci.c:593 > > #6 0x00000000005b9738 in pci_devices_iommu_support_va () > > at /root/dpdk/drivers/bus/pci/linux/pci.c:626 > > #7 0x00000000005b97a7 in rte_pci_get_iommu_class () > > at /root/dpdk/drivers/bus/pci/linux/pci.c:650 > > #8 0x000000000058f1ce in rte_bus_get_iommu_class () > > at /root/dpdk/lib/librte_eal/common/eal_common_bus.c:237 > > #9 0x0000000000577c7a in rte_eal_init (argc=2, argv=0x7fffffffdf98) > > at /root/dpdk/lib/librte_eal/linuxapp/eal/eal.c:919 > > #10 0x000000000045dd56 in main (argc=2, argv=0x7fffffffdf98) > > at /root/dpdk/examples/multi_process/hotplug_mp/main.c:28 > > > > > > Best regards, > > Xueqin > > > > *From:* Alejandro Lucero [mailto:alejandro.luc...@netronome.com] > *Sent:* Monday, October 29, 2018 9:41 PM > *To:* Yao, Lei A <lei.a....@intel.com> > *Cc:* Thomas Monjalon <tho...@monjalon.net>; dev <dev@dpdk.org>; Xu, Qian > Q <qian.q...@intel.com>; Lin, Xueqin <xueqin....@intel.com>; Burakov, > Anatoly <anatoly.bura...@intel.com>; Yigit, Ferruh <ferruh.yi...@intel.com > > > *Subject:* Re: [dpdk-dev] [PATCH v3 0/6] use IOVAs check based on DMA mask > > > > > > On Mon, Oct 29, 2018 at 1:18 PM Yao, Lei A <lei.a....@intel.com> wrote: > > > > > > *From:* Alejandro Lucero [mailto:alejandro.luc...@netronome.com] > *Sent:* Monday, October 29, 2018 8:56 PM > *To:* Thomas Monjalon <tho...@monjalon.net> > *Cc:* Yao, Lei A <lei.a....@intel.com>; dev <dev@dpdk.org>; Xu, Qian Q < > qian.q...@intel.com>; Lin, Xueqin <xueqin....@intel.com>; Burakov, > Anatoly <anatoly.bura...@intel.com>; Yigit, Ferruh <ferruh.yi...@intel.com > > > *Subject:* Re: [dpdk-dev] [PATCH v3 0/6] use IOVAs check based on DMA mask > > > > > > On Mon, Oct 29, 2018 at 11:46 AM Thomas Monjalon <tho...@monjalon.net> > wrote: > > 29/10/2018 12:39, Alejandro Lucero: > > I got a patch that solves a bug when calling rte_eal_dma_mask using the > > mask instead of the maskbits. However, this does not solves the > deadlock. > > The deadlock is a bigger concern I think. > > > > I think once the call to rte_eal_check_dma_mask uses the maskbits instead > of the mask, calling rte_memseg_walk_thread_unsafe avoids the deadlock. > > > > Yao, can you try with the attached patch? > > > > Hi, Lucero > > > > This patch can fix the issue at my side. Thanks a lot > > for you quick action. > > > > > > Great! > > > > I will send an official patch with the changes. > > > > I have to say that I tested the patchset, but I think it was where > legacy_mem was still there and therefore dynamic memory allocation code not > used during memory initialization. > > > > There is something that concerns me though. Using > rte_memseg_walk_thread_unsafe could be a problem under some situations > although those situations being unlikely. > > > > Usually, calling rte_eal_check_dma_mask happens during initialization. > Then it is safe to use the unsafe function for walking memsegs, but with > device hotplug and dynamic memory allocation, there exists a potential race > condition when the primary process is allocating more memory and > concurrently a device is hotplugged and a secondary process does the device > initialization. By now, this is just a problem with the NFP, and the > potential race condition window really unlikely, but I will work on this > asap. > > > > BRs > > Lei > > > > > Interestingly, the problem looks like a compiler one. Calling > > rte_memseg_walk does not return when calling inside rt_eal_dma_mask, > but if > > you modify the call like this: > > > > - if (rte_memseg_walk(check_iova, &mask)) > > + if (!rte_memseg_walk(check_iova, &mask)) > > > > it works, although the value returned to the invoker changes, of course. > > But the point here is it should be the same behaviour when calling > > rte_memseg_walk than before and it is not. > > Anyway, the coding style requires to save the return value in a variable, > instead of nesting the call in an "if" condition. > And the "if" check should be explicitly != 0 because it is not a real > boolean. > > PS: please do not top post and avoid HTML emails, thanks > >
