The patch titled
Subject: vmscan: convert page buffer handling to use folios
has been added to the -mm mm-unstable branch. Its filename is
vmscan-convert-page-buffer-handling-to-use-folios.patch
This patch should soon appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: vmscan: convert page buffer handling to use folios
This mostly just removes calls to compound_head() although nr_reclaimed
should be incremented by the number of pages, not just 1.
Link: https://lkml.kernel.org/r/20220429192329.3034378-10-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 48 +++++++++++++++++++++++++-----------------------
1 file changed, 25 insertions(+), 23 deletions(-)
--- a/mm/vmscan.c~vmscan-convert-page-buffer-handling-to-use-folios
+++ a/mm/vmscan.c
@@ -1859,38 +1859,40 @@ retry:
}
/*
- * If the page has buffers, try to free the buffer mappings
- * associated with this page. If we succeed we try to free
- * the page as well.
+ * If the folio has buffers, try to free the buffer
+ * mappings associated with this folio. If we succeed
+ * we try to free the folio as well.
*
- * We do this even if the page is PageDirty().
- * try_to_release_page() does not perform I/O, but it is
- * possible for a page to have PageDirty set, but it is actually
- * clean (all its buffers are clean). This happens if the
- * buffers were written out directly, with submit_bh(). ext3
- * will do this, as well as the blockdev mapping.
- * try_to_release_page() will discover that cleanness and will
- * drop the buffers and mark the page clean - it can be freed.
+ * We do this even if the folio is dirty.
+ * filemap_release_folio() does not perform I/O, but it
+ * is possible for a folio to have the dirty flag set,
+ * but it is actually clean (all its buffers are clean).
+ * This happens if the buffers were written out directly,
+ * with submit_bh(). ext3 will do this, as well as
+ * the blockdev mapping. filemap_release_folio() will
+ * discover that cleanness and will drop the buffers
+ * and mark the folio clean - it can be freed.
*
- * Rarely, pages can have buffers and no ->mapping. These are
- * the pages which were not successfully invalidated in
- * truncate_cleanup_page(). We try to drop those buffers here
- * and if that worked, and the page is no longer mapped into
- * process address space (page_count == 1) it can be freed.
- * Otherwise, leave the page on the LRU so it is swappable.
+ * Rarely, folios can have buffers and no ->mapping.
+ * These are the folios which were not successfully
+ * invalidated in truncate_cleanup_folio(). We try to
+ * drop those buffers here and if that worked, and the
+ * folio is no longer mapped into process address space
+ * (refcount == 1) it can be freed. Otherwise, leave
+ * the folio on the LRU so it is swappable.
*/
- if (page_has_private(page)) {
- if (!try_to_release_page(page, sc->gfp_mask))
+ if (folio_has_private(folio)) {
+ if (!filemap_release_folio(folio, sc->gfp_mask))
goto activate_locked;
- if (!mapping && page_count(page) == 1) {
- unlock_page(page);
- if (put_page_testzero(page))
+ if (!mapping && folio_ref_count(folio) == 1) {
+ folio_unlock(folio);
+ if (folio_put_testzero(folio))
goto free_it;
else {
/*
* rare race with speculative reference.
* the speculative reference will free
- * this page shortly, so we may
+ * this folio shortly, so we may
* increment nr_reclaimed here (and
* leave it off the LRU).
*/
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
shmem-convert-shmem_alloc_hugepage-to-use-vma_alloc_folio.patch
mm-huge_memory-convert-do_huge_pmd_anonymous_page-to-use-vma_alloc_folio.patch
mm-remove-alloc_pages_vma.patch
vmscan-use-folio_mapped-in-shrink_page_list.patch
vmscan-convert-the-writeback-handling-in-shrink_page_list-to-folios.patch
swap-turn-get_swap_page-into-folio_alloc_swap.patch
swap-convert-add_to_swap-to-take-a-folio.patch
vmscan-convert-dirty-page-handling-to-folios.patch
vmscan-convert-page-buffer-handling-to-use-folios.patch
vmscan-convert-lazy-freeing-to-folios.patch
vmscan-move-initialisation-of-mapping-down.patch
vmscan-convert-the-activate_locked-portion-of-shrink_page_list-to-folios.patch
vmscan-remove-remaining-uses-of-page-in-shrink_page_list.patch
mm-shmem-use-a-folio-in-shmem_unused_huge_shrink.patch
mm-swap-add-folio_throttle_swaprate.patch
mm-shmem-convert-shmem_add_to_page_cache-to-take-a-folio.patch
mm-shmem-turn-shmem_should_replace_page-into-shmem_should_replace_folio.patch
mm-shmem-turn-shmem_alloc_page-into-shmem_alloc_folio.patch
mm-shmem-convert-shmem_alloc_and_acct_page-to-use-a-folio.patch
mm-shmem-convert-shmem_getpage_gfp-to-use-a-folio.patch
mm-shmem-convert-shmem_swapin_page-to-shmem_swapin_folio.patch
vmcore-convert-copy_oldmem_page-to-take-an-iov_iter.patch
vmcore-convert-__read_vmcore-to-use-an-iov_iter.patch
vmcore-convert-read_from_oldmem-to-take-an-iov_iter.patch
