Re: [PATCH v3 20/20] mm: stop maintaining the per-page mapcount of large folios (CONFIG_NO_PAGE_MAPCOUNT)
From: Wei Yang <hidden>
Date: 2025-10-14 12:23:38
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On Mon, Mar 03, 2025 at 05:30:13PM +0100, David Hildenbrand wrote: [...]
quoted hunk ↗ jump to hunk
@@ -1678,6 +1726,22 @@ static __always_inline void __folio_remove_rmap(struct folio *folio,break; case RMAP_LEVEL_PMD: case RMAP_LEVEL_PUD: + if (IS_ENABLED(CONFIG_NO_PAGE_MAPCOUNT)) { + last = atomic_add_negative(-1, &folio->_entire_mapcount); + if (level == RMAP_LEVEL_PMD && last) + nr_pmdmapped = folio_large_nr_pages(folio); + nr = folio_dec_return_large_mapcount(folio, vma); + if (!nr) { + /* Now completely unmapped. */ + nr = folio_large_nr_pages(folio); + } else { + partially_mapped = last && + nr < folio_large_nr_pages(folio);
Hi, David Do you think this is better to be? partially_mapped = last && nr < nr_pmdmapped; As commit 349994cf61e6 mentioned, we don't support partially mapped PUD-sized folio yet. Not sure what I missed here.
+ nr = 0;
+ }
+ break;
+ }
+
folio_dec_large_mapcount(folio, vma);
last = atomic_add_negative(-1, &folio->_entire_mapcount);
if (last) {
--
2.48.1-- Wei Yang Help you, Help me