Re: [PATCH] mm/vmscan: Fix hard LOCKUP in function isolate_lru_folios

[Andrew Morton]

On Wed, 25 Sep 2024 16:37:14 +0800 liuye <liuye@xxxxxxxxxx> wrote:

> 
> 
> On 2024/9/25 上午8:22, Andrew Morton wrote:
> > On Wed, 14 Aug 2024 17:18:25 +0800 liuye <liuye@xxxxxxxxxx> wrote:
> > 
> >> @@ -1669,10 +1670,12 @@ static unsigned long isolate_lru_folios(unsigned long nr_to_scan,
> >>  		nr_pages = folio_nr_pages(folio);
> >>  		total_scan += nr_pages;
> >>  
> >> -		if (folio_zonenum(folio) > sc->reclaim_idx ||
> >> -				skip_cma(folio, sc)) {
> >> +		/* Using max_nr_skipped to prevent hard LOCKUP*/
> >> +		if ((max_nr_skipped < SWAP_CLUSTER_MAX_SKIPPED) &&
> >> +			(folio_zonenum(folio) > sc->reclaim_idx || skip_cma(folio, sc))) {
> >>  			nr_skipped[folio_zonenum(folio)] += nr_pages;
> >>  			move_to = &folios_skipped;
> >> +			max_nr_skipped++;
> >>  			goto move;
> > 
> > This hunk is not applicable to current mainline.
> > 
> 
> Please see the PATCH v2 in link [1], and the related discussion in link [2].
> Then please explain why it is not applicable,thank you.

What I mean is that the patch doesn't apply.

Current mainline has

		if (folio_zonenum(folio) > sc->reclaim_idx) {
			nr_skipped[folio_zonenum(folio)] += nr_pages;
			move_to = &folios_skipped;
			goto move;
		}