Re: [PATCH] mm/show_mem: Optimize si_meminfo_node by reducing redundant code
From: Mike Rapoport
Date: Wed Mar 26 2025 - 15:29:26 EST
On Tue, Mar 25, 2025 at 03:38:03PM +0800, Ye Liu wrote:
> From: Ye Liu <liuye@xxxxxxxxxx>
>
> Refactors the si_meminfo_node() function by reducing redundant code and
> improving readability.
>
> Moved the calculation of managed_pages inside the existing loop that
> processes pgdat->node_zones, eliminating the need for a separate loop.
>
> Simplified the logic by removing unnecessary preprocessor conditionals.
>
> Ensured that both totalram, totalhigh, and other memory statistics are
> consistently set without duplication.
>
> This change results in cleaner and more efficient code without altering
> functionality.
>
> Signed-off-by: Ye Liu <liuye@xxxxxxxxxx>
> ---
> mm/show_mem.c | 16 +++++-----------
> 1 file changed, 5 insertions(+), 11 deletions(-)
>
> diff --git a/mm/show_mem.c b/mm/show_mem.c
> index 6af13bcd2ab3..ad373b4b6e39 100644
> --- a/mm/show_mem.c
> +++ b/mm/show_mem.c
> @@ -94,26 +94,20 @@ void si_meminfo_node(struct sysinfo *val, int nid)
> unsigned long free_highpages = 0;
> pg_data_t *pgdat = NODE_DATA(nid);
>
> - for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++)
> - managed_pages += zone_managed_pages(&pgdat->node_zones[zone_type]);
> - val->totalram = managed_pages;
> - val->sharedram = node_page_state(pgdat, NR_SHMEM);
> - val->freeram = sum_zone_node_page_state(nid, NR_FREE_PAGES);
> -#ifdef CONFIG_HIGHMEM
> for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
> struct zone *zone = &pgdat->node_zones[zone_type];
> -
> + managed_pages += zone_managed_pages(zone);
nit: don't remove the empty line after the declaration
> if (is_highmem(zone)) {
> managed_highpages += zone_managed_pages(zone);
Looks like highmem pages get counted twice, no?
> free_highpages += zone_page_state(zone, NR_FREE_PAGES);
> }
> }
> +
> + val->totalram = managed_pages;
> + val->sharedram = node_page_state(pgdat, NR_SHMEM);
> + val->freeram = sum_zone_node_page_state(nid, NR_FREE_PAGES);
> val->totalhigh = managed_highpages;
> val->freehigh = free_highpages;
> -#else
> - val->totalhigh = managed_highpages;
> - val->freehigh = free_highpages;
> -#endif
> val->mem_unit = PAGE_SIZE;
> }
> #endif
> --
> 2.25.1
>
>
--
Sincerely yours,
Mike.