From: Thomas Monjalon <thomas@monjalon.net>
To: Anatoly Burakov <anatoly.burakov@intel.com>
Cc: dev@dpdk.org, ray.kinsella@intel.com,
kuralamudhan.ramakrishnan@intel.com, louise.m.daly@intel.com,
bruce.richardson@intel.com, ferruh.yigit@intel.com,
konstantin.ananyev@intel.com
Subject: Re: [dpdk-dev] [PATCH v2 9/9] mem: support in-memory mode
Date: Fri, 13 Jul 2018 14:15:44 +0200 [thread overview]
Message-ID: <2386265.Zj3uxajx9O@xps> (raw)
In-Reply-To: <8fef5019ebdb9d941c1ade936fcdda1ace303738.1531477505.git.anatoly.burakov@intel.com>
There is a compilation error:
../lib/librte_eal/linuxapp/eal/eal_memalloc.c: In function ‘alloc_seg’:
../lib/librte_eal/linuxapp/eal/eal_memalloc.c:619:3: error:
‘map_offset’ may be used uninitialized in this function
13/07/2018 12:27, Anatoly Burakov:
> Implement the final piece of the in-memory mode puzzle - enable running
> DPDK entirely in memory, without creating any files.
>
> To do it, use mmap with MAP_HUGETLB and size flags to enable DPDK to work
> without hugetlbfs mountpoints. In order to enable this, a few things needed
> to be changed.
>
> First of all, we need to allow empty hugetlbfs mountpoints in
> hugepage_info, and handle them correctly (by not trying to create any
> files and lock any directories).
>
> Next, we need to reorder the mapping sequence, because the page is not
> really allocated until the page fault, and we cannot get its IOVA
> address before we trigger the page fault.
>
> Finally, decide at compile time whether we are going to be supporting
> anonymous hugepages or not, because we cannot check for it at runtime.
>
> Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
> ---
>
> Notes:
> RFC->v1:
> - Drop memfd and instead use mmap() with MAP_HUGETLB. This will drop the
> kernel requirements down to 3.8, and does not impose any restrictions
> glibc (as far as i known).
>
> Unfortunately, there's a bit of an issue with this approach, because
> mmap() is stupid and will happily ignore unsupported arguments. This
> means that if the binary were to be compiled on a 3.8+ kernel but run
> on a pre-3.8 kernel (such as currently supported minimum of 3.2), then
> most likely the memory would be allocated using regular pages, causing
> unthinkable performance degradation. No solution to this problem is
> currently known to me.
prev parent reply other threads:[~2018-07-13 12:15 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-01 17:15 [dpdk-dev] [PATCH 0/9] Support running DPDK without hugetlbfs mountpoint Anatoly Burakov
2018-06-01 17:15 ` [dpdk-dev] [PATCH 1/9] fbarray: support no-shconf mode Anatoly Burakov
2018-06-01 17:15 ` [dpdk-dev] [PATCH 2/9] ipc: add support for " Anatoly Burakov
2018-06-01 17:15 ` [dpdk-dev] [PATCH 3/9] eal: add support for no-shconf for hugepage info Anatoly Burakov
2018-06-01 17:15 ` [dpdk-dev] [PATCH 4/9] eal: add support for no-shconf in hugepage data file Anatoly Burakov
2018-06-01 17:15 ` [dpdk-dev] [PATCH 5/9] eal: do not create runtime dir in no-shconf mode Anatoly Burakov
2018-06-01 17:15 ` [dpdk-dev] [PATCH 6/9] mem: add support for hugepage-unlink mode Anatoly Burakov
2018-06-01 17:15 ` [dpdk-dev] [PATCH 7/9] eal: add --in-memory option Anatoly Burakov
2018-06-01 17:15 ` [dpdk-dev] [PATCH 8/9] doc: add deprecation notice for EAL command line options Anatoly Burakov
2018-06-01 17:15 ` [dpdk-dev] [PATCH 9/9] mem: support in-memory mode Anatoly Burakov
2018-07-13 10:27 ` [dpdk-dev] [PATCH v2 0/9] Support running DPDK without hugetlbfs mountpoint Anatoly Burakov
2018-07-13 12:47 ` [dpdk-dev] [PATCH v3 0/8] " Anatoly Burakov
2018-07-13 13:41 ` Thomas Monjalon
2018-07-13 12:47 ` [dpdk-dev] [PATCH v3 1/8] fbarray: support no-shconf mode Anatoly Burakov
2018-07-13 12:47 ` [dpdk-dev] [PATCH v3 2/8] ipc: add support for " Anatoly Burakov
2018-07-13 12:47 ` [dpdk-dev] [PATCH v3 3/8] eal: add support for no-shconf for hugepage info Anatoly Burakov
2018-07-13 12:48 ` [dpdk-dev] [PATCH v3 4/8] eal: add support for no-shconf in hugepage data file Anatoly Burakov
2018-07-13 12:48 ` [dpdk-dev] [PATCH v3 5/8] eal: do not create runtime dir in no-shconf mode Anatoly Burakov
2018-07-13 12:48 ` [dpdk-dev] [PATCH v3 6/8] mem: add support for hugepage-unlink mode Anatoly Burakov
2018-07-13 12:48 ` [dpdk-dev] [PATCH v3 7/8] eal: add --in-memory option Anatoly Burakov
2018-07-13 12:48 ` [dpdk-dev] [PATCH v3 8/8] mem: support in-memory mode Anatoly Burakov
2018-07-13 10:27 ` [dpdk-dev] [PATCH v2 1/9] fbarray: support no-shconf mode Anatoly Burakov
2018-07-13 10:27 ` [dpdk-dev] [PATCH v2 2/9] ipc: add support for " Anatoly Burakov
2018-07-13 10:27 ` [dpdk-dev] [PATCH v2 3/9] eal: add support for no-shconf for hugepage info Anatoly Burakov
2018-07-13 10:27 ` [dpdk-dev] [PATCH v2 4/9] eal: add support for no-shconf in hugepage data file Anatoly Burakov
2018-07-13 10:27 ` [dpdk-dev] [PATCH v2 5/9] eal: do not create runtime dir in no-shconf mode Anatoly Burakov
2018-07-13 10:27 ` [dpdk-dev] [PATCH v2 6/9] mem: add support for hugepage-unlink mode Anatoly Burakov
2018-07-13 10:27 ` [dpdk-dev] [PATCH v2 7/9] eal: add --in-memory option Anatoly Burakov
2018-07-13 12:13 ` Thomas Monjalon
2018-07-13 12:27 ` Burakov, Anatoly
2018-07-13 10:27 ` [dpdk-dev] [PATCH v2 8/9] doc: add deprecation notice for EAL command line options Anatoly Burakov
2018-07-13 12:13 ` Thomas Monjalon
2018-07-13 12:29 ` Burakov, Anatoly
2018-07-13 10:27 ` [dpdk-dev] [PATCH v2 9/9] mem: support in-memory mode Anatoly Burakov
2018-07-13 12:15 ` Thomas Monjalon [this message]
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