mm: move mm counter updating out of set_pte_range()

Patch series "mm: batch mm counter updating in filemap_map_pages()", v3.

Let's batch mm counter updating to accelerate filemap_map_pages().


This patch (of 2):

In order to support batch mm counter updating in filemap_map_pages(), move
mm counter updating out of set_pte_range(), the folios are file from
filemap, and distinguish folios by vmf->flags and vma->vm_flags from
another caller finish_fault().

Link: https://lkml.kernel.org/r/20240412064751.119015-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240412064751.119015-2-wangkefeng.wang@huawei.comSigned-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/filemap.c

@@ -3539,6 +3539,8 @@ static vm_fault_t filemap_map_folio_range(struct vm_fault *vmf,
 skip:
 		if (count) {
 			set_pte_range(vmf, folio, page, count, addr);
+			add_mm_counter(vmf->vma->vm_mm, mm_counter_file(folio),
+				       count);
 			folio_ref_add(folio, count);
 			if (in_range(vmf->address, addr, count * PAGE_SIZE))
 				ret = VM_FAULT_NOPAGE;
@@ -3553,6 +3555,7 @@ static vm_fault_t filemap_map_folio_range(struct vm_fault *vmf,
 
 	if (count) {
 		set_pte_range(vmf, folio, page, count, addr);
+		add_mm_counter(vmf->vma->vm_mm, mm_counter_file(folio), count);
 		folio_ref_add(folio, count);
 		if (in_range(vmf->address, addr, count * PAGE_SIZE))
 			ret = VM_FAULT_NOPAGE;
@@ -3589,6 +3592,7 @@ static vm_fault_t filemap_map_order0_folio(struct vm_fault *vmf,
 		ret = VM_FAULT_NOPAGE;
 
 	set_pte_range(vmf, folio, page, 1, addr);
+	add_mm_counter(vmf->vma->vm_mm, mm_counter_file(folio), 1);
 	folio_ref_inc(folio);
 
 	return ret;

mm/memory.c

@@ -4687,12 +4687,10 @@ void set_pte_range(struct vm_fault *vmf, struct folio *folio,
 		entry = pte_mkuffd_wp(entry);
 	/* copy-on-write page */
 	if (write && !(vma->vm_flags & VM_SHARED)) {
-		add_mm_counter(vma->vm_mm, MM_ANONPAGES, nr);
 		VM_BUG_ON_FOLIO(nr != 1, folio);
 		folio_add_new_anon_rmap(folio, vma, addr);
 		folio_add_lru_vma(folio, vma);
 	} else {
-		add_mm_counter(vma->vm_mm, mm_counter_file(folio), nr);
 		folio_add_file_rmap_ptes(folio, page, nr, vma);
 	}
 	set_ptes(vma->vm_mm, addr, vmf->pte, entry, nr);
@@ -4729,9 +4727,11 @@ vm_fault_t finish_fault(struct vm_fault *vmf)
 	struct vm_area_struct *vma = vmf->vma;
 	struct page *page;
 	vm_fault_t ret;
+	bool is_cow = (vmf->flags & FAULT_FLAG_WRITE) &&
+		      !(vma->vm_flags & VM_SHARED);
 
 	/* Did we COW the page? */
-	if ((vmf->flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED))
+	if (is_cow)
 		page = vmf->cow_page;
 	else
 		page = vmf->page;
@@ -4767,8 +4767,10 @@ vm_fault_t finish_fault(struct vm_fault *vmf)
 	/* Re-check under ptl */
 	if (likely(!vmf_pte_changed(vmf))) {
 		struct folio *folio = page_folio(page);
+		int type = is_cow ? MM_ANONPAGES : mm_counter_file(folio);
 
 		set_pte_range(vmf, folio, page, 1, vmf->address);
+		add_mm_counter(vma->vm_mm, type, 1);
 		ret = 0;
 	} else {
 		update_mmu_tlb(vma, vmf->address, vmf->pte);