[Bug 1068199] Re: please add support for MAP_HUGETLB in eglibc for Lucid

[Rolf Leggewie]

lucid has seen the end of its life and is no longer receiving any
updates. Marking the lucid task for this ticket as "Won't Fix".

** Changed in: eglibc (Ubuntu Lucid)
       Status: Confirmed => Won't Fix

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Title:
  please add support for MAP_HUGETLB in eglibc for Lucid

Status in Lucid Backports:
  Fix Released
Status in eglibc package in Ubuntu:
  Invalid
Status in libhugetlbfs package in Ubuntu:
  Invalid
Status in eglibc source package in Lucid:
  Won't Fix
Status in libhugetlbfs source package in Lucid:
  Invalid

Bug description:
  it looks like eglibc on 10.04 does not have MAP_HUGETLB headers or
  flags activated [1].

  According to hugetlbpage.txt [2] they state that if the application is making use of only (shmget, shmat) calls you don't really
  need a virtual filesystem. This behaviout *DOES NOT* happen on 10.04 using the released hugepages 10.04 packages but it DOES WORK when using precise packages.

  [Impact]
  Those wishing utilize hugepages on Lucid.

  [Test Case]
  Here are some steps to reproduce the issue.

  1. Configure hugepages with filesystem support.
  2. Test and validate that it works with 10.04 packages.
  3. Umount the virtual filesystem
  sudo umount /mnt/hugetlbfs
  4. run:
  LD_PRELOAD=libhugetlbfs.so HUGETLB_MORECORE=yes ls /boot
  You will get the following error message:
  libhugetlbfs: WARNING: Hugepage size 2097152 unavailable
  abi-2.6.32-43-server grub lost+found System.map-2.6.32-43-server vmlinuz-2.6.32-43-server

  5. Download hugepages packages from:
  https://launchpad.net/ubuntu/+source/libhugetlbfs/2.11-0ubuntu1/+build/2263743 and install them.

  6. Try again. It should work without having to configure a virtual
  filesystem.

  [1] - http://old.nabble.com/Missing-MAP_HUGETLB-flag-from-glibc-headers-td30201924.html
  [2] - http://www.kernel.org/doc/Documentation/vm/hugetlbpage.txt

  Leonardo Borda

  [Regressioni Potential]
  Huge page support is already in the kernel so this impact is merely making use of that functionality. There should be no changes needed in current applications since hugepages can be used through existing shmget,shmat routines.

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