Add function to do file page mapping based on folio and update
filemap_map_pages() to use new function. So the filemap page
mapping will deal with folio granularity instead of page
granularity. This allow batched folio refcount update.
Signed-off-by: Yin Fengwei <fengwei.yin@xxxxxxxxx>
---
mm/filemap.c | 82 ++++++++++++++++++++++++++++++----------------------
1 file changed, 48 insertions(+), 34 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index c915ded191f0..fe0c226c8b1e 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3351,6 +3351,43 @@ static inline struct folio *next_map_page(struct address_space *mapping,
mapping, xas, end_pgoff);
}
+
+static vm_fault_t filemap_map_folio_range(struct vm_fault *vmf,
+ struct folio *folio, struct page *page, unsigned long addr,
+ int len)
+{
+ vm_fault_t ret = 0;
+ struct vm_area_struct *vma = vmf->vma;
+ struct file *file = vma->vm_file;
+ unsigned int mmap_miss = READ_ONCE(file->f_ra.mmap_miss);
+ int ref_count = 0, count = 0;
+
+ do {
+ if (PageHWPoison(page))
+ continue;
+
+ if (mmap_miss > 0)
+ mmap_miss--;
+
+ if (!pte_none(*vmf->pte))
+ continue;
+
+ if (vmf->address == addr)
+ ret = VM_FAULT_NOPAGE;
+
+ ref_count++;
+
+ do_set_pte(vmf, page, addr);
+ update_mmu_cache(vma, addr, vmf->pte);
+
+ } while (vmf->pte++, page++, addr += PAGE_SIZE, ++count < len);
+
+ folio_ref_add(folio, ref_count);
+ WRITE_ONCE(file->f_ra.mmap_miss, mmap_miss);
+
+ return ret;
+}
+
vm_fault_t filemap_map_pages(struct vm_fault *vmf,
pgoff_t start_pgoff, pgoff_t end_pgoff)
{
@@ -3361,9 +3398,9 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf,
unsigned long addr;
XA_STATE(xas, &mapping->i_pages, start_pgoff);
struct folio *folio;
- struct page *page;
unsigned int mmap_miss = READ_ONCE(file->f_ra.mmap_miss);
vm_fault_t ret = 0;
+ int len = 0;
rcu_read_lock();
folio = first_map_page(mapping, &xas, end_pgoff);
@@ -3378,45 +3415,22 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf,
addr = vma->vm_start + ((start_pgoff - vma->vm_pgoff) << PAGE_SHIFT);
vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, addr, &vmf->ptl);
do {
-again:
- page = folio_file_page(folio, xas.xa_index);
- if (PageHWPoison(page))
- goto unlock;
-
- if (mmap_miss > 0)
- mmap_miss--;
+ struct page *page;
+ unsigned long end;
+ page = folio_file_page(folio, xas.xa_index);
addr += (xas.xa_index - last_pgoff) << PAGE_SHIFT;
- vmf->pte += xas.xa_index - last_pgoff;
+ vmf->pte += xas.xa_index - last_pgoff - len;
last_pgoff = xas.xa_index;
+ end = folio->index + folio_nr_pages(folio) - 1;
+ len = min(end, end_pgoff) - xas.xa_index + 1;
- /*
- * NOTE: If there're PTE markers, we'll leave them to be
- * handled in the specific fault path, and it'll prohibit the
- * fault-around logic.
- */
- if (!pte_none(*vmf->pte))
- goto unlock;
-
- /* We're about to handle the fault */
- if (vmf->address == addr)
+ if (VM_FAULT_NOPAGE ==
+ filemap_map_folio_range(vmf, folio, page, addr, len))
ret = VM_FAULT_NOPAGE;
- do_set_pte(vmf, page, addr);
- /* no need to invalidate: a not-present page won't be cached */
- update_mmu_cache(vma, addr, vmf->pte);
- if (folio_more_pages(folio, xas.xa_index, end_pgoff)) {
- xas.xa_index++;
- folio_ref_inc(folio);
- goto again;
- }
- folio_unlock(folio);
- continue;
-unlock:
- if (folio_more_pages(folio, xas.xa_index, end_pgoff)) {
- xas.xa_index++;
- goto again;
- }
+ xas.xa_index = end;
+
folio_unlock(folio);
folio_put(folio);
} while ((folio = next_map_page(mapping, &xas, end_pgoff)) != NULL);
--
2.30.2
