On Wed, Sep 16, 2020 at 10:11 AM Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote:
>
> Hi,
> Please see comments below.
>
> On 9/15/20 5:59 AM, Muchun Song wrote:
> > Add a kernel parameter hugetlb_free_vmemmap to disable the feature of
> > freeing unused vmemmap pages associated with each hugetlb page on boot.
> >
> > Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
> > ---
> > .../admin-guide/kernel-parameters.txt | 9 ++++++++
> > Documentation/admin-guide/mm/hugetlbpage.rst | 3 +++
> > mm/hugetlb.c | 23 +++++++++++++++++++
> > 3 files changed, 35 insertions(+)
> >
> > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> > index 5debfe238027..69d18ef6f66b 100644
> > --- a/Documentation/admin-guide/kernel-parameters.txt
> > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > @@ -1551,6 +1551,15 @@
> > Documentation/admin-guide/mm/hugetlbpage.rst.
> > Format: size[KMG]
> >
> > + hugetlb_free_vmemmap=
> > + [KNL] When CONFIG_HUGETLB_PAGE_FREE_VMEMMAP is set,
> > + this disables freeing unused vmemmap pages associated
>
> this controls
>
> > + each HugeTLB page.
>
> with each HugeTLB page.
>
> > + Format: { on (default) | off }
> > +
> > + on: enable the feature
> > + off: dosable the feature
>
> disable
>
> > +
> > hung_task_panic=
> > [KNL] Should the hung task detector generate panics.
> > Format: 0 | 1
> > diff --git a/Documentation/admin-guide/mm/hugetlbpage.rst b/Documentation/admin-guide/mm/hugetlbpage.rst
> > index f7b1c7462991..7d6129ee97dd 100644
> > --- a/Documentation/admin-guide/mm/hugetlbpage.rst
> > +++ b/Documentation/admin-guide/mm/hugetlbpage.rst
> > @@ -145,6 +145,9 @@ default_hugepagesz
> >
> > will all result in 256 2M huge pages being allocated. Valid default
> > huge page size is architecture dependent.
>
> insert blank line here.
>
> > +hugetlb_free_vmemmap
> > + When CONFIG_HUGETLB_PAGE_FREE_VMEMMAP is set, this disables freeing
> > + unused vmemmap pages associated each HugeTLB page.
> >
> > When multiple huge page sizes are supported, ``/proc/sys/vm/nr_hugepages``
> > indicates the current number of pre-allocated huge pages of the default size.
>
Thanks for your comments.
>
> --
> ~Randy
>
--
Yours,
Muchun
