On Mon, 9 May 2016 12:53:38 -0500
Reza Arbab <ar...@linux.vnet.ibm.com> wrote:
> When memory is onlined, we are only able to rezone from ZONE_MOVABLE to
> ZONE_KERNEL, or from (ZONE_MOVABLE - 1) to ZONE_MOVABLE.
>
> To be more flexible, use the following criteria instead; to online memory
> from zone X into zone Y,
>
> * Any zones between X and Y must be unused.
> * If X is lower than Y, the onlined memory must lie at the end of X.
> * If X is higher than Y, the onlined memory must lie at the start of X.
>
> Add zone_can_shift() to make this determination.
>
> Signed-off-by: Reza Arbab <ar...@linux.vnet.ibm.com>
> ---
Looks good to me.
Reviewd-by: Yasuaki Ishimatsu <isimatu.yasu...@jp.fujitsu.com>
Thanks,
Yasuaki Ishimatsu
> include/linux/memory_hotplug.h | 2 ++
> mm/memory_hotplug.c | 42
> +++++++++++++++++++++++++++++++++++-------
> 2 files changed, 37 insertions(+), 7 deletions(-)
>
> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
> index adbef58..7bff0f9 100644
> --- a/include/linux/memory_hotplug.h
> +++ b/include/linux/memory_hotplug.h
> @@ -284,5 +284,7 @@ extern void sparse_remove_one_section(struct zone *zone,
> struct mem_section *ms,
> unsigned long map_offset);
> extern struct page *sparse_decode_mem_map(unsigned long coded_mem_map,
> unsigned long pnum);
> +extern int zone_can_shift(unsigned long pfn, unsigned long nr_pages,
> + enum zone_type target);
>
> #endif /* __LINUX_MEMORY_HOTPLUG_H */
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 6b4b005..b63cc28 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1032,6 +1032,37 @@ static void node_states_set_node(int node, struct
> memory_notify *arg)
> node_set_state(node, N_MEMORY);
> }
>
> +int zone_can_shift(unsigned long pfn, unsigned long nr_pages,
> + enum zone_type target)
> +{
> + struct zone *zone = page_zone(pfn_to_page(pfn));
> + enum zone_type idx = zone_idx(zone);
> + int i;
> +
> + if (idx < target) {
> + /* pages must be at end of current zone */
> + if (pfn + nr_pages != zone_end_pfn(zone))
> + return 0;
> +
> + /* no zones in use between current zone and target */
> + for (i = idx + 1; i < target; i++)
> + if (zone_is_initialized(zone - idx + i))
> + return 0;
> + }
> +
> + if (target < idx) {
> + /* pages must be at beginning of current zone */
> + if (pfn != zone->zone_start_pfn)
> + return 0;
> +
> + /* no zones in use between current zone and target */
> + for (i = target + 1; i < idx; i++)
> + if (zone_is_initialized(zone - idx + i))
> + return 0;
> + }
> +
> + return target - idx;
> +}
>
> /* Must be protected by mem_hotplug_begin() */
> int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int
> online_type)
> @@ -1057,13 +1088,10 @@ int __ref online_pages(unsigned long pfn, unsigned
> long nr_pages, int online_typ
> !can_online_high_movable(zone))
> return -EINVAL;
>
> - if (online_type == MMOP_ONLINE_KERNEL &&
> - zone_idx(zone) == ZONE_MOVABLE)
> - zone_shift = -1;
> -
> - if (online_type == MMOP_ONLINE_MOVABLE &&
> - zone_idx(zone) == ZONE_MOVABLE - 1)
> - zone_shift = 1;
> + if (online_type == MMOP_ONLINE_KERNEL)
> + zone_shift = zone_can_shift(pfn, nr_pages, ZONE_NORMAL);
> + else if (online_type == MMOP_ONLINE_MOVABLE)
> + zone_shift = zone_can_shift(pfn, nr_pages, ZONE_MOVABLE);
>
> zone = move_pfn_range(zone_shift, pfn, pfn + nr_pages);
> if (!zone)
> --
> 1.8.3.1
>
> --
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