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> LIST_HEAD(ret_folios); > LIST_HEAD(demote_folios); > + LIST_HEAD(pageout_list); > unsigned int nr_reclaimed = 0; > unsigned int pgactivate = 0; > bool do_demote_pass; > @@ -1351,39 +1352,9 @@ static unsigned int shrink_folio_list(struct > list_head *folio_list, > if (!sc->may_writepage) > goto keep_locked; > > - /* > - * Folio is dirty. Flush the TLB if a writable entry > - * potentially exists to avoid CPU writes after I/O > - * starts and then write it out here. > - */ > - try_to_unmap_flush_dirty(); > - switch (pageout(folio, mapping, &plug)) { > - case PAGE_KEEP: > - goto keep_locked; > - case PAGE_ACTIVATE: > - goto activate_locked; > - case PAGE_SUCCESS: > - stat->nr_pageout += nr_pages; > - > - if (folio_test_writeback(folio)) > - goto keep; > - if (folio_test_dirty(folio)) > - goto keep; > - > - /* > - * A synchronous write - probably a ramdisk. Go > - * ahead and try to reclaim the folio. > - */ > - if (!folio_trylock(folio)) > - goto keep; > - if (folio_test_dirty(folio) || > - folio_test_writeback(folio)) > - goto keep_locked; > - mapping = folio_mapping(folio); > - fallthrough; > - case PAGE_CLEAN: > - ; /* try to free the folio below */ > - } > + /* Add to pageout list for defered bio submissions */ > + list_add(&folio->lru, &pageout_list); > + continue; The dirty pages are collected in a list here... > } > > /* > @@ -1494,6 +1465,76 @@ static unsigned int shrink_folio_list(struct > list_head *folio_list, > } > /* 'folio_list' is always empty here */ > > + if (!list_empty(&pageout_list)) { > + /* > + * Batch TLB flushes by flushing once before processing > all dirty pages. > + * Since we operate on one PMD at a time, this batches > TLB flushes at > + * PMD granularity rather than per-page, reducing IPIs. > + */ > + struct address_space *mapping; > + try_to_unmap_flush_dirty(); and one flush request is issued for the entire list. Where is the PMD level (512) batching done? Is that implicit elsewhere in the flow? > + > + while (!list_empty(&pageout_list)) { > + struct folio *folio = lru_to_folio(&pageout_list); > + list_del(&folio->lru); > + > + /* Recheck if page got reactivated */ > + if (folio_test_active(folio) || > + (folio_mapped(folio) && folio_test_young(folio))) > + goto skip_pageout_locked; > + > + mapping = folio_mapping(folio); > + pageout_t pageout_res = pageout(folio, mapping, &plug); > + switch (pageout_res) { > + case PAGE_KEEP: > + goto skip_pageout_locked; > + case PAGE_ACTIVATE: > + goto skip_pageout_locked; > + case PAGE_SUCCESS: > + stat->nr_pageout += folio_nr_pages(folio); > + > + if (folio_test_writeback(folio) || > + folio_test_dirty(folio)) > + goto skip_pageout; > + > + /* > + * A synchronous write - probably a ramdisk. Go > + * ahead and try to reclaim the folio. > + */ > + if (!folio_trylock(folio)) > + goto skip_pageout; > + if (folio_test_dirty(folio) || > + folio_test_writeback(folio)) > + goto skip_pageout_locked; > + > + // Try to free the page > + if (!mapping || > + !__remove_mapping(mapping, folio, true, > + sc->target_mem_cgroup)) > + goto skip_pageout_locked; > + > + nr_reclaimed += folio_nr_pages(folio); > + folio_unlock(folio); > + continue; > + > + case PAGE_CLEAN: > + if (!mapping || > + !__remove_mapping(mapping, folio, true, > + sc->target_mem_cgroup)) > + goto skip_pageout_locked; > + > + nr_reclaimed += folio_nr_pages(folio); > + folio_unlock(folio); > + continue; > + } > + > +skip_pageout_locked: > + folio_unlock(folio); > +skip_pageout: > + list_add(&folio->lru, &ret_folios); > + } > + } > + > /* Migrate folios selected for demotion */ > nr_reclaimed += demote_folio_list(&demote_folios, pgdat); > /* Folios that could not be demoted are still in @demote_folios */ Regards, Bharata.