Re: [PATCH v1 1/3] mm: process_mrelease: expedite clean file folio reclaim via mmu_gather

[Alexander Gordeev]

On Fri, May 08, 2026 at 02:56:35PM -0700, Minchan Kim wrote:

Hi Minchan,

> > > +void free_pages_and_caches(struct mm_struct *mm, struct encoded_page **pages, int nr)
> > > +{
> > > +	bool try_evict_file_folios = mm_flags_test(MMF_UNSTABLE, mm);
> > > +	struct folio_batch folios;
> > > +	unsigned int refs[PAGEVEC_SIZE];
> > > +
> > > +	folio_batch_init(&folios);
> > > +	for (int i = 0; i < nr; i++) {
> > > +		struct folio *folio = page_folio(encoded_page_ptr(pages[i]));
> > > +
> > > +		if (folio_test_anon(folio))
> > > +			free_swap_cache(folio);
> > > +		else if (unlikely(try_evict_file_folios))
> > > +			free_file_cache(folio);
> > 
> > This condition is absent in free_pages_and_swap_cache().
> > What would happen with non-anon and non-evict folio?
> 
> Are you asking about mlocked pages for file?
> 
> During unmapping, munlock_vma_folio() inside __folio_remove_rmap() clears
> the PG_mlocked flag and moves the folio back to the evictable LRU list.
> 
> By the time the folios reach free_pages_and_caches(), if the folio is
> exclusive, it will be successfully evicted. However, if the folio is shared,
> mapping_evict_folio() detects it via the refcount check and skips the
> eviction.
> 
> However, I realized we miss shmem folios in the swap cache due to the new
> folio_test_anon() check we introduced. I will update the check to something
> like this:
> 
> if (folio_test_swapcache(folio))
>     free_swap_cache(folio);

This condition looks redundant, since free_swap_cache() checks it too.

> else if (unlikely(try_evict_file_folios))
>     free_file_cache(folio);
> 
> Let me know if I missed something from your point.


Thanks!

> Thank you.