From fb72415938d109fe8cca339a4f1423f76ba213c5 Mon Sep 17 00:00:00 2001 From: Baolin Wang Date: Mon, 12 Aug 2024 15:42:05 +0800 Subject: [PATCH] mm: filemap: use xa_get_order() to get the swap entry order In the following patches, shmem will support the swap out of large folios, which means the shmem mappings may contain large order swap entries, so using xa_get_order() to get the folio order of the shmem swap entry to update the '*start' correctly. [hughd@google.com: use xa_get_order() to get the swap entry order] Link: https://lkml.kernel.org/r/c336e6e4-da7f-b714-c0f1-12df715f2611@google.com Link: https://lkml.kernel.org/r/6876d55145c1cc80e79df7884aa3a62e397b101d.1723434324.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang Signed-off-by: Hugh Dickins Cc: Barry Song Cc: Chris Li Cc: Daniel Gomez Cc: David Hildenbrand Cc: "Huang, Ying" Cc: Kefeng Wang Cc: Lance Yang Cc: Matthew Wilcox Cc: Pankaj Raghav Cc: Ryan Roberts Cc: Yang Shi Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/filemap.c | 41 +++++++++++++++++++++++++++-------------- 1 file changed, 27 insertions(+), 14 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index fcfec2a78a30..fdaa1e5e3078 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2046,17 +2046,20 @@ unsigned find_get_entries(struct address_space *mapping, pgoff_t *start, if (!folio_batch_add(fbatch, folio)) break; } - rcu_read_unlock(); if (folio_batch_count(fbatch)) { - unsigned long nr = 1; + unsigned long nr; int idx = folio_batch_count(fbatch) - 1; folio = fbatch->folios[idx]; if (!xa_is_value(folio)) nr = folio_nr_pages(folio); - *start = indices[idx] + nr; + else + nr = 1 << xa_get_order(&mapping->i_pages, indices[idx]); + *start = round_down(indices[idx] + nr, nr); } + rcu_read_unlock(); + return folio_batch_count(fbatch); } @@ -2088,10 +2091,17 @@ unsigned find_lock_entries(struct address_space *mapping, pgoff_t *start, rcu_read_lock(); while ((folio = find_get_entry(&xas, end, XA_PRESENT))) { + unsigned long base; + unsigned long nr; + if (!xa_is_value(folio)) { - if (folio->index < *start) + nr = folio_nr_pages(folio); + base = folio->index; + /* Omit large folio which begins before the start */ + if (base < *start) goto put; - if (folio_next_index(folio) - 1 > end) + /* Omit large folio which extends beyond the end */ + if (base + nr - 1 > end) goto put; if (!folio_trylock(folio)) goto put; @@ -2100,7 +2110,19 @@ unsigned find_lock_entries(struct address_space *mapping, pgoff_t *start, goto unlock; VM_BUG_ON_FOLIO(!folio_contains(folio, xas.xa_index), folio); + } else { + nr = 1 << xa_get_order(&mapping->i_pages, xas.xa_index); + base = xas.xa_index & ~(nr - 1); + /* Omit order>0 value which begins before the start */ + if (base < *start) + continue; + /* Omit order>0 value which extends beyond the end */ + if (base + nr - 1 > end) + break; } + + /* Update start now so that last update is correct on return */ + *start = base + nr; indices[fbatch->nr] = xas.xa_index; if (!folio_batch_add(fbatch, folio)) break; @@ -2112,15 +2134,6 @@ put: } rcu_read_unlock(); - if (folio_batch_count(fbatch)) { - unsigned long nr = 1; - int idx = folio_batch_count(fbatch) - 1; - - folio = fbatch->folios[idx]; - if (!xa_is_value(folio)) - nr = folio_nr_pages(folio); - *start = indices[idx] + nr; - } return folio_batch_count(fbatch); } -- 2.25.1