Messages in this thread | | | Date | Thu, 17 Aug 2023 09:39:54 -0700 | From | Jerry Snitselaar <> | Subject | Re: [PATCH 0/2] iommu/iova: Make the rcache depot properly flexible |
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On Mon, Aug 14, 2023 at 06:53:32PM +0100, Robin Murphy wrote: > Hi all, > > Prompted by [1], which reminded me I started this a while ago, I've now > finished off my own attempt at sorting out the horrid lack of rcache > scalability. It's become quite clear that given the vast range of system > sizes and workloads there is no right size for a fixed depot array, so I > reckon we're better off not having one at all. > > Note that the reclaim threshold and rate are chosen fairly arbitrarily - > it's enough of a challenge to get my 4-core dev board with spinning disk > and gigabit ethernet to push anything into a depot at all :) > > Thanks, > Robin. > > [1] https://lore.kernel.org/linux-iommu/20230811130246.42719-1-zhangzekun11@huawei.com > > > Robin Murphy (2): > iommu/iova: Make the rcache depot scale better > iommu/iova: Manage the depot list size > > drivers/iommu/iova.c | 94 ++++++++++++++++++++++++++++++-------------- > 1 file changed, 65 insertions(+), 29 deletions(-) > > -- > 2.39.2.101.g768bb238c484.dirty >
I'm trying to hunt down a system where we've seen some issues before, but most of them have involved systems with nvme drives. Commit 3710e2b056cb ("nvme-pci: clamp max_hw_sectors based on DMA optimized limitation") has helped those cases. I ran the patches overnight with IOVA_DEPOT_DELAY fixed up on a couple of Genoa based systems (384 cores) without issue.
Regards, Jerry
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