17/01/2022 09:14, Dmitry Kozlyuk: > Expose Linux EAL ability to reuse existing hugepage files > via --huge-unlink=never switch. > Default behavior is unchanged, it can also be specified > using --huge-unlink=existing for consistency. > Old --huge-unlink switch is kept, > it is an alias for --huge-unlink=always. > > Signed-off-by: Dmitry Kozlyuk <dkozl...@nvidia.com> > --- > doc/guides/linux_gsg/linux_eal_parameters.rst | 21 ++++++++-- > .../prog_guide/env_abstraction_layer.rst | 9 +++++ > doc/guides/rel_notes/release_22_03.rst | 7 ++++ > lib/eal/common/eal_common_options.c | 39 +++++++++++++++++-- > 4 files changed, 69 insertions(+), 7 deletions(-) > > diff --git a/doc/guides/linux_gsg/linux_eal_parameters.rst > b/doc/guides/linux_gsg/linux_eal_parameters.rst > index 74df2611b5..7586f15ce3 100644 > --- a/doc/guides/linux_gsg/linux_eal_parameters.rst > +++ b/doc/guides/linux_gsg/linux_eal_parameters.rst > @@ -84,10 +84,23 @@ Memory-related options > Use specified hugetlbfs directory instead of autodetected ones. This can > be > a sub-directory within a hugetlbfs mountpoint. > > -* ``--huge-unlink`` > - > - Unlink hugepage files after creating them (implies no secondary process > - support). > +* ``--huge-unlink[=existing|always|never]`` > + > + No ``--huge-unlink`` option or ``--huge-unlink=existing`` is the default: > + existing hugepage files are removed and re-created > + to ensure the kernel clears the memory and prevents any data leaks. > + > + With ``--huge-unlink`` (no value) or ``--huge-unlink=always``, > + hugepage files are also removed after creating them, > + so that the application leaves no files in hugetlbfs. > + This mode implies no multi-process support. > + > + When ``--huge-unlink=never`` is specified, existing hugepage files > + are not removed either before or after mapping them.
One detail not clear: the second unlink is before or after mapping? > + This makes restart faster by saving time to clear memory at > initialization, > + but it may slow down zeroed allocations later. > + Reused hugepages can contain data from previous processes that used them, > + which may be a security concern. I absolutely love these options. It keeps compability while making things consistent and understandable. Acked-by: Thomas Monjalon <tho...@monjalon.net>
