Re: [RFC PATCH v3 1/7] mm/damon/paddr: refactor DAMOS_PAGEOUT with migration_mode

SeongJae Park
2024-04-05T19:19:10Z

On Fri, 5 Apr 2024 15:08:50 +0900 Honggyu Kim <honggyu.kim@sk.com> wrote:

> This is a preparation patch that introduces migration modes.
>
> The damon_pa_pageout is renamed to damon_pa_migrate and it receives an
> extra argument for migration_mode.

I personally think keeping damon_pa_pageout() as is and adding a new function
(damon_pa_migrate()) with some duplicated code is also ok, but this approach
also looks fine to me. So I have no strong opinion here, but just letting you
know I would have no objection at both approaches.

>
> No functional changes applied.
>
> Signed-off-by: Honggyu Kim <honggyu.kim@sk.com>
> ---
> mm/damon/paddr.c | 18 +++++++++++++++---
> 1 file changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
> index 081e2a325778..277a1c4d833c 100644
> --- a/mm/damon/paddr.c
> +++ b/mm/damon/paddr.c
> @@ -224,7 +224,12 @@ static bool damos_pa_filter_out(struct damos *scheme, struct folio *folio)
> return false;
> }
>
> -static unsigned long damon_pa_pageout(struct damon_region *r, struct damos *s)
> +enum migration_mode {
> + MIG_PAGEOUT,
> +};

To avoid name conflicts, what about renaming to 'damos_migration_mode' and
'DAMOS_MIG_PAGEOUT'?

> +
> +static unsigned long damon_pa_migrate(struct damon_region *r, struct damos *s,
> + enum migration_mode mm)

My poor brain has a bit confused with the name. What about calling it 'mode'?

> {
> unsigned long addr, applied;
> LIST_HEAD(folio_list);
> @@ -249,7 +254,14 @@ static unsigned long damon_pa_pageout(struct damon_region *r, struct damos *s)
> put_folio:
> folio_put(folio);
> }
> - applied = reclaim_pages(&folio_list);
> + switch (mm) {
> + case MIG_PAGEOUT:
> + applied = reclaim_pages(&folio_list);
> + break;
> + default:
> + /* Unexpected migration mode. */
> + return 0;
> + }
> cond_resched();
> return applied * PAGE_SIZE;
> }
> @@ -297,7 +309,7 @@ static unsigned long damon_pa_apply_scheme(struct damon_ctx *ctx,
> {
> switch (scheme->action) {
> case DAMOS_PAGEOUT:
> - return damon_pa_pageout(r, scheme);
> + return damon_pa_migrate(r, scheme, MIG_PAGEOUT);
> case DAMOS_LRU_PRIO:
> return damon_pa_mark_accessed(r, scheme);
> case DAMOS_LRU_DEPRIO:
> --
> 2.34.1

Thanks,
SJ