The patch titled
Subject: rmap: add folio_add_file_rmap_range()
has been added to the -mm mm-unstable branch. Its filename is
rmap-add-folio_add_file_rmap_range.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/rmap-add-folio_add_file_rmap_range.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Yin Fengwei <fengwei.yin@xxxxxxxxx>
Subject: rmap: add folio_add_file_rmap_range()
Date: Mon, 10 Jul 2023 21:43:36 +0100
folio_add_file_rmap_range() allows to add pte mapping to a specific range
of file folio. Comparing to page_add_file_rmap(), it batched updates
__lruvec_stat for large folio.
Link: https://lkml.kernel.org/r/20230710204339.3554919-36-willy@xxxxxxxxxxxxx
Signed-off-by: Yin Fengwei <fengwei.yin@xxxxxxxxx>
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/rmap.h | 2 +
mm/rmap.c | 60 +++++++++++++++++++++++++++++++----------
2 files changed, 48 insertions(+), 14 deletions(-)
--- a/include/linux/rmap.h~rmap-add-folio_add_file_rmap_range
+++ a/include/linux/rmap.h
@@ -198,6 +198,8 @@ void folio_add_new_anon_rmap(struct foli
unsigned long address);
void page_add_file_rmap(struct page *, struct vm_area_struct *,
bool compound);
+void folio_add_file_rmap_range(struct folio *, struct page *, unsigned int nr,
+ struct vm_area_struct *, bool compound);
void page_remove_rmap(struct page *, struct vm_area_struct *,
bool compound);
--- a/mm/rmap.c~rmap-add-folio_add_file_rmap_range
+++ a/mm/rmap.c
@@ -1306,31 +1306,39 @@ void folio_add_new_anon_rmap(struct foli
}
/**
- * page_add_file_rmap - add pte mapping to a file page
- * @page: the page to add the mapping to
+ * folio_add_file_rmap_range - add pte mapping to page range of a folio
+ * @folio: The folio to add the mapping to
+ * @page: The first page to add
+ * @nr_pages: The number of pages which will be mapped
* @vma: the vm area in which the mapping is added
* @compound: charge the page as compound or small page
*
+ * The page range of folio is defined by [first_page, first_page + nr_pages)
+ *
* The caller needs to hold the pte lock.
*/
-void page_add_file_rmap(struct page *page, struct vm_area_struct *vma,
- bool compound)
+void folio_add_file_rmap_range(struct folio *folio, struct page *page,
+ unsigned int nr_pages, struct vm_area_struct *vma,
+ bool compound)
{
- struct folio *folio = page_folio(page);
atomic_t *mapped = &folio->_nr_pages_mapped;
- int nr = 0, nr_pmdmapped = 0;
- bool first;
+ unsigned int nr_pmdmapped = 0, first;
+ int nr = 0;
- VM_BUG_ON_PAGE(compound && !PageTransHuge(page), page);
+ VM_WARN_ON_FOLIO(compound && !folio_test_pmd_mappable(folio), folio);
/* Is page being mapped by PTE? Is this its first map to be added? */
if (likely(!compound)) {
- first = atomic_inc_and_test(&page->_mapcount);
- nr = first;
- if (first && folio_test_large(folio)) {
- nr = atomic_inc_return_relaxed(mapped);
- nr = (nr < COMPOUND_MAPPED);
- }
+ do {
+ first = atomic_inc_and_test(&page->_mapcount);
+ if (first && folio_test_large(folio)) {
+ first = atomic_inc_return_relaxed(mapped);
+ first = (first < COMPOUND_MAPPED);
+ }
+
+ if (first)
+ nr++;
+ } while (page++, --nr_pages > 0);
} else if (folio_test_pmd_mappable(folio)) {
/* That test is redundant: it's for safety or to optimize out */
@@ -1360,6 +1368,30 @@ void page_add_file_rmap(struct page *pag
}
/**
+ * page_add_file_rmap - add pte mapping to a file page
+ * @page: the page to add the mapping to
+ * @vma: the vm area in which the mapping is added
+ * @compound: charge the page as compound or small page
+ *
+ * The caller needs to hold the pte lock.
+ */
+void page_add_file_rmap(struct page *page, struct vm_area_struct *vma,
+ bool compound)
+{
+ struct folio *folio = page_folio(page);
+ unsigned int nr_pages;
+
+ VM_WARN_ON_ONCE_PAGE(compound && !PageTransHuge(page), page);
+
+ if (likely(!compound))
+ nr_pages = 1;
+ else
+ nr_pages = folio_nr_pages(folio);
+
+ folio_add_file_rmap_range(folio, page, nr_pages, vma, compound);
+}
+
+/**
* page_remove_rmap - take down pte mapping from a page
* @page: page to remove mapping from
* @vma: the vm area from which the mapping is removed
_
Patches currently in -mm which might be from fengwei.yin@xxxxxxxxx are
filemap-add-filemap_map_folio_range.patch
rmap-add-folio_add_file_rmap_range.patch
mm-convert-do_set_pte-to-set_pte_range.patch
filemap-batch-pte-mappings.patch
