Re: [PATCH v3 0/4] mm/page_reporting: Make page reporting work on arm64 with 64KB page size

[Alexander Duyck <alexander.duyck@gmail.com>]

So the series looks okay, although I would strongly suggest getting to
work on the virtio_ballon patches to enable reporting the min_order of
the host so that you can override the value in cases where the host is
actually using 512M pages.

For the series:
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>

On Tue, Jun 22, 2021 at 5:34 PM Gavin Shan <gshan@redhat.com> wrote:
>
> The page reporting threshold is currently equal to @pageblock_order, which
> is 13 and 512MB on arm64 with 64KB base page size selected. The page
> reporting won't be triggered if the freeing page can't come up with a free
> area like that huge. The condition is hard to be met, especially when the
> system memory becomes fragmented.
>
> This series intends to solve the issue by having page reporting threshold
> as 5 (2MB) on arm64 with 64KB base page size. The patches are organized as:
>
>    PATCH[1/4] Fix some coding style in __page_reporting_request().
>    PATCH[2/4] Represents page reporting order with variable so that it can
>               be exported as module parameter.
>    PATCH[3/4] Allows the device driver (e.g. virtio_balloon) to specify
>               the page reporting order when the device info is registered.
>    PATCH[4/4] Specifies the page reporting order to 5, corresponding to
>               2MB in size on ARM64 when 64KB base page size is used.
>
> Changelog
> =========
> v3:
>    * Avoid overhead introduced by function all                    (Alex)
>    * Export page reporting order as module parameter              (Gavin)
> v2:
>    * Rewrite the patches as Alex suggested                        (Alex)
>
> Gavin Shan (4):
>   mm/page_reporting: Fix code style in __page_reporting_request()
>   mm/page_reporting: Export reporting order as module parameter
>   mm/page_reporting: Allow driver to specify reporting order
>   virtio_balloon: Specify page reporting order if needed
>
>  Documentation/admin-guide/kernel-parameters.txt |  6 ++++++
>  drivers/virtio/virtio_balloon.c                 | 17 +++++++++++++++++
>  include/linux/page_reporting.h                  |  3 +++
>  mm/page_reporting.c                             | 16 ++++++++++++----
>  mm/page_reporting.h                             |  5 ++---
>  5 files changed, 40 insertions(+), 7 deletions(-)
>
> --
> 2.23.0
>