On 2024/5/8 17:55, Chengming Zhou wrote:
> During testing, I found ksm_pages_scanned is unchanged although the
> scan_get_next_rmap_item() did return valid rmap_item that is not NULL.
>
> The reason is the scan_get_next_rmap_item() will return NULL after
> a full scan, so ksm_do_scan() just return without accounting of the
> ksm_pages_scanned.
>
> Fix it by just putting ksm_pages_scanned accounting in that loop,
> and it will be accounted more timely if that loop would last for
> a long time.
>
Fixes: b348b5fe2b5f ("mm/ksm: add pages scanned metric")
> Signed-off-by: Chengming Zhou <chengming.zhou@xxxxxxxxx>
> ---
> mm/ksm.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/mm/ksm.c b/mm/ksm.c
> index e1034bf1c937..0f9c491552ff 100644
> --- a/mm/ksm.c
> +++ b/mm/ksm.c
> @@ -2753,18 +2753,16 @@ static void ksm_do_scan(unsigned int scan_npages)
> {
> struct ksm_rmap_item *rmap_item;
> struct page *page;
> - unsigned int npages = scan_npages;
>
> - while (npages-- && likely(!freezing(current))) {
> + while (scan_npages-- && likely(!freezing(current))) {
> cond_resched();
> rmap_item = scan_get_next_rmap_item(&page);
> if (!rmap_item)
> return;
> cmp_and_merge_page(page, rmap_item);
> put_page(page);
> + ksm_pages_scanned++;
> }
> -
> - ksm_pages_scanned += scan_npages - npages;
> }
>
> static int ksmd_should_run(void)
>
