On Fri, May 26, 2023 at 08:52:50AM +0000, Haifeng Xu wrote:
> Currently, no matter whether a node actually has memory or not,
> calculate_node_totalpages() is used to account number of pages
> in zone/node. However, for node without memory, these unnecessary
> calculations can be skipped. All the zone/node page counts can be
> set to 0 directly. So introduce reset_memoryless_node_totalpages()
> to perform this action.
>
> Furthermore, calculate_node_totalpages() only gets called for the
> node with memory.
>
> Signed-off-by: Haifeng Xu <haifeng.xu@xxxxxxxxxx>
> Suggested-by: Mike Rapoport <rppt@xxxxxxxxxx>
Reviewed-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
> ---
> v2:
> - drop patch 2 in v1
> - inroduce new function reset_memoryless_node_totalpages()
> - call calculate_node_totalpages only if node actually has
> memory
> ---
> mm/mm_init.c | 31 ++++++++++++++++++++++---------
> 1 file changed, 22 insertions(+), 9 deletions(-)
>
> diff --git a/mm/mm_init.c b/mm/mm_init.c
> index 7f7f9c677854..f674e5798f7d 100644
> --- a/mm/mm_init.c
> +++ b/mm/mm_init.c
> @@ -1174,10 +1174,6 @@ static unsigned long __init zone_absent_pages_in_node(int nid,
> unsigned long zone_start_pfn, zone_end_pfn;
> unsigned long nr_absent;
>
> - /* When hotadd a new node from cpu_up(), the node should be empty */
> - if (!node_start_pfn && !node_end_pfn)
> - return 0;
> -
> zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
> zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
>
> @@ -1227,9 +1223,6 @@ static unsigned long __init zone_spanned_pages_in_node(int nid,
> {
> unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
> unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
> - /* When hotadd a new node from cpu_up(), the node should be empty */
> - if (!node_start_pfn && !node_end_pfn)
> - return 0;
>
> /* Get the start and end of the zone */
> *zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
> @@ -1250,6 +1243,24 @@ static unsigned long __init zone_spanned_pages_in_node(int nid,
> return *zone_end_pfn - *zone_start_pfn;
> }
>
> +static void __init reset_memoryless_node_totalpages(struct pglist_data *pgdat)
> +{
> + struct zone *z;
> +
> + for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++) {
> + z->zone_start_pfn = 0;
> + z->spanned_pages = 0;
> + z->present_pages = 0;
> +#if defined(CONFIG_MEMORY_HOTPLUG)
> + z->present_early_pages = 0;
> +#endif
> + }
> +
> + pgdat->node_spanned_pages = 0;
> + pgdat->node_present_pages = 0;
> + pr_debug("On node %d totalpages: 0\n", pgdat->node_id);
> +}
> +
> static void __init calculate_node_totalpages(struct pglist_data *pgdat,
> unsigned long node_start_pfn,
> unsigned long node_end_pfn)
> @@ -1702,11 +1713,13 @@ static void __init free_area_init_node(int nid)
> pr_info("Initmem setup node %d [mem %#018Lx-%#018Lx]\n", nid,
> (u64)start_pfn << PAGE_SHIFT,
> end_pfn ? ((u64)end_pfn << PAGE_SHIFT) - 1 : 0);
> +
> + calculate_node_totalpages(pgdat, start_pfn, end_pfn);
> } else {
> pr_info("Initmem setup node %d as memoryless\n", nid);
> - }
>
> - calculate_node_totalpages(pgdat, start_pfn, end_pfn);
> + reset_memoryless_node_totalpages(pgdat);
> + }
>
> alloc_node_mem_map(pgdat);
> pgdat_set_deferred_range(pgdat);
> --
> 2.25.1
>
--
Sincerely yours,
Mike.
