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From: bugzilla@dpdk.org
To: dev@dpdk.org
Subject: [Bug 893] no_hugetlbfs should not mean legacy_mem on iommu/vfio platforms
Date: Fri, 03 Dec 2021 02:17:40 +0000	[thread overview]
Message-ID: <bug-893-3@http.bugs.dpdk.org/> (raw)

https://bugs.dpdk.org/show_bug.cgi?id=893

            Bug ID: 893
           Summary: no_hugetlbfs should not mean legacy_mem on iommu/vfio
                    platforms
           Product: DPDK
           Version: unspecified
          Hardware: All
                OS: All
            Status: UNCONFIRMED
          Severity: normal
          Priority: Normal
         Component: core
          Assignee: dev@dpdk.org
          Reporter: niketkandya@google.com
  Target Milestone: ---

From my reading of the code and docs this is what I understand:
1. Huge pages are needed by DPDK so that user pages are always present and
pinned.
2. In systems with IOMMU and VFIO support, there should be no need for huge
pages. VFIO_IOMMU_MAP_DMA on any aligned buffer should do the same pinning.

--no-hugetlbfs today means that the system is also in --legacy-mem (which means
no dynamic allocation, 1 fixed heap of 64MB MEMSIZE_IF_NO_HUGE). I think this
is restrictive.
On systems with IOMMU/VFIO support --no-hugetlbfs should also support
dynamic(non legacy behavior) allocation.

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                 reply	other threads:[~2021-12-03  2:17 UTC|newest]

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