From: Alex Williamson <alex.williamson@redhat.com>
To: Shenming Lu <lushenming@huawei.com>
Cc: Cornelia Huck <cohuck@redhat.com>, Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Joerg Roedel <joro@8bytes.org>,
Jean-Philippe Brucker <jean-philippe@linaro.org>,
Eric Auger <eric.auger@redhat.com>, <kvm@vger.kernel.org>,
<linux-kernel@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<iommu@lists.linux-foundation.org>, <linux-api@vger.kernel.org>,
Kevin Tian <kevin.tian@intel.com>,
Lu Baolu <baolu.lu@linux.intel.com>, <yi.l.liu@intel.com>,
Christoph Hellwig <hch@infradead.org>,
Jonathan Cameron <Jonathan.Cameron@huawei.com>,
Barry Song <song.bao.hua@hisilicon.com>,
<wanghaibin.wang@huawei.com>, <yuzenghui@huawei.com>
Subject: Re: [RFC PATCH v3 4/8] vfio/type1: Pre-map more pages than requested in the IOPF handling
Date: Tue, 18 May 2021 12:58:26 -0600 [thread overview]
Message-ID: <20210518125826.7ba38b78.alex.williamson@redhat.com> (raw)
In-Reply-To: <20210409034420.1799-5-lushenming@huawei.com>
On Fri, 9 Apr 2021 11:44:16 +0800
Shenming Lu <lushenming@huawei.com> wrote:
> To optimize for fewer page fault handlings, we can pre-map more pages
> than requested at once.
>
> Note that IOPF_PREMAP_LEN is just an arbitrary value for now, which we
> could try further tuning.
I'd prefer that the series introduced full end-to-end functionality
before trying to improve performance. The pre-map value seems
arbitrary here and as noted in the previous patch, the IOMMU API does
not guarantee unmaps of ranges smaller than the original mapping. This
would need to map with single page granularity in order to guarantee
page granularity at the mmu notifier when the IOMMU supports
superpages. Thanks,
Alex
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next prev parent reply other threads:[~2021-05-18 19:03 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-09 3:44 [RFC PATCH v3 0/8] Add IOPF support for VFIO passthrough Shenming Lu
2021-04-09 3:44 ` [RFC PATCH v3 1/8] iommu: Evolve the device fault reporting framework Shenming Lu
2021-05-18 18:58 ` Alex Williamson
2021-05-21 6:37 ` Shenming Lu
2021-04-09 3:44 ` [RFC PATCH v3 2/8] vfio/type1: Add a page fault handler Shenming Lu
2021-05-18 18:58 ` Alex Williamson
2021-05-21 6:38 ` Shenming Lu
2021-05-24 22:11 ` Alex Williamson
2021-05-27 11:16 ` Shenming Lu
2021-04-09 3:44 ` [RFC PATCH v3 3/8] vfio/type1: Add an MMU notifier to avoid pinning Shenming Lu
2021-05-18 18:58 ` Alex Williamson
2021-05-21 6:37 ` Shenming Lu
2021-04-09 3:44 ` [RFC PATCH v3 4/8] vfio/type1: Pre-map more pages than requested in the IOPF handling Shenming Lu
2021-05-18 18:58 ` Alex Williamson [this message]
2021-05-21 6:37 ` Shenming Lu
2021-04-09 3:44 ` [RFC PATCH v3 5/8] vfio/type1: VFIO_IOMMU_ENABLE_IOPF Shenming Lu
2021-05-18 18:58 ` Alex Williamson
2021-05-21 6:38 ` Shenming Lu
2021-05-24 22:11 ` Alex Williamson
2021-05-27 11:15 ` Shenming Lu
2021-04-09 3:44 ` [RFC PATCH v3 6/8] vfio/type1: No need to statically pin and map if IOPF enabled Shenming Lu
2021-05-18 18:58 ` Alex Williamson
2021-05-21 6:39 ` Shenming Lu
2021-04-09 3:44 ` [RFC PATCH v3 7/8] vfio/type1: Add selective DMA faulting support Shenming Lu
2021-05-18 18:58 ` Alex Williamson
2021-05-21 6:39 ` Shenming Lu
2021-04-09 3:44 ` [RFC PATCH v3 8/8] vfio: Add nested IOPF support Shenming Lu
2021-05-18 18:58 ` Alex Williamson
2021-05-21 7:59 ` Shenming Lu
2021-05-24 13:11 ` Shenming Lu
2021-05-24 22:11 ` Alex Williamson
2021-05-27 11:03 ` Shenming Lu
2021-05-27 11:18 ` Lu Baolu
2021-06-01 4:36 ` Shenming Lu
2021-04-26 1:41 ` [RFC PATCH v3 0/8] Add IOPF support for VFIO passthrough Shenming Lu
2021-05-11 11:30 ` Shenming Lu
2021-05-18 18:57 ` Alex Williamson
2021-05-21 6:37 ` Shenming Lu
2021-05-24 22:11 ` Alex Williamson
2021-05-27 11:25 ` Shenming Lu
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