+ mm-filemap-batch-mm-counter-updating-in-filemap_map_pages.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm: filemap: batch mm counter updating in filemap_map_pages()
has been added to the -mm mm-unstable branch.  Its filename is
     mm-filemap-batch-mm-counter-updating-in-filemap_map_pages.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-filemap-batch-mm-counter-updating-in-filemap_map_pages.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: Kefeng Wang <wangkefeng.wang@huawei.com>
Subject: mm: filemap: batch mm counter updating in filemap_map_pages()
Date: Fri, 12 Apr 2024 14:47:51 +0800

Like copy_pte_range()/zap_pte_range(), make mm counter batch updating in
filemap_map_pages(), since folios type are same(MM_SHMEMPAGES or
MM_FILEPAGES) in filemap_map_pages(), only check the first folio type is
enough, the 'lat_pagefault -P 1 file' test from lmbench shows 12%
improvement, and the percpu_counter_add_batch() is gone from perf flame
graph.

Link: https://lkml.kernel.org/r/20240412064751.119015-3-wangkefeng.wang@huawei.com
Signed-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 |   21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

--- a/mm/filemap.c~mm-filemap-batch-mm-counter-updating-in-filemap_map_pages
+++ a/mm/filemap.c
@@ -3505,7 +3505,7 @@ skip:
 static vm_fault_t filemap_map_folio_range(struct vm_fault *vmf,
 			struct folio *folio, unsigned long start,
 			unsigned long addr, unsigned int nr_pages,
-			unsigned int *mmap_miss)
+			unsigned long *rss, unsigned int *mmap_miss)
 {
 	vm_fault_t ret = 0;
 	struct page *page = folio_page(folio, start);
@@ -3539,8 +3539,7 @@ static vm_fault_t filemap_map_folio_rang
 skip:
 		if (count) {
 			set_pte_range(vmf, folio, page, count, addr);
-			add_mm_counter(vmf->vma->vm_mm, mm_counter_file(folio),
-				       count);
+			*rss += count;
 			folio_ref_add(folio, count);
 			if (in_range(vmf->address, addr, count * PAGE_SIZE))
 				ret = VM_FAULT_NOPAGE;
@@ -3555,7 +3554,7 @@ skip:
 
 	if (count) {
 		set_pte_range(vmf, folio, page, count, addr);
-		add_mm_counter(vmf->vma->vm_mm, mm_counter_file(folio), count);
+		*rss += count;
 		folio_ref_add(folio, count);
 		if (in_range(vmf->address, addr, count * PAGE_SIZE))
 			ret = VM_FAULT_NOPAGE;
@@ -3568,7 +3567,7 @@ skip:
 
 static vm_fault_t filemap_map_order0_folio(struct vm_fault *vmf,
 		struct folio *folio, unsigned long addr,
-		unsigned int *mmap_miss)
+		unsigned long *rss, unsigned int *mmap_miss)
 {
 	vm_fault_t ret = 0;
 	struct page *page = &folio->page;
@@ -3592,7 +3591,7 @@ static vm_fault_t filemap_map_order0_fol
 		ret = VM_FAULT_NOPAGE;
 
 	set_pte_range(vmf, folio, page, 1, addr);
-	add_mm_counter(vmf->vma->vm_mm, mm_counter_file(folio), 1);
+	(*rss)++;
 	folio_ref_inc(folio);
 
 	return ret;
@@ -3609,7 +3608,8 @@ vm_fault_t filemap_map_pages(struct vm_f
 	XA_STATE(xas, &mapping->i_pages, start_pgoff);
 	struct folio *folio;
 	vm_fault_t ret = 0;
-	unsigned int nr_pages = 0, mmap_miss = 0, mmap_miss_saved;
+	unsigned long rss = 0;
+	unsigned int nr_pages = 0, mmap_miss = 0, mmap_miss_saved, folio_type;
 
 	rcu_read_lock();
 	folio = next_uptodate_folio(&xas, mapping, end_pgoff);
@@ -3628,6 +3628,8 @@ vm_fault_t filemap_map_pages(struct vm_f
 		folio_put(folio);
 		goto out;
 	}
+
+	folio_type = mm_counter_file(folio);
 	do {
 		unsigned long end;
 
@@ -3639,15 +3641,16 @@ vm_fault_t filemap_map_pages(struct vm_f
 
 		if (!folio_test_large(folio))
 			ret |= filemap_map_order0_folio(vmf,
-					folio, addr, &mmap_miss);
+					folio, addr, &rss, &mmap_miss);
 		else
 			ret |= filemap_map_folio_range(vmf, folio,
 					xas.xa_index - folio->index, addr,
-					nr_pages, &mmap_miss);
+					nr_pages, &rss, &mmap_miss);
 
 		folio_unlock(folio);
 		folio_put(folio);
 	} while ((folio = next_uptodate_folio(&xas, mapping, end_pgoff)) != NULL);
+	add_mm_counter(vma->vm_mm, folio_type, rss);
 	pte_unmap_unlock(vmf->pte, vmf->ptl);
 out:
 	rcu_read_unlock();
_

Patches currently in -mm which might be from wangkefeng.wang@huawei.com are

mm-backing-dev-use-group-allocation-free-of-per-cpu-counters-api.patch
mm-remove-__set_page_dirty_nobuffers.patch
arm64-mm-cleanup-__do_page_fault.patch
arm64-mm-accelerate-pagefault-when-vm_fault_badaccess.patch
arm-mm-accelerate-pagefault-when-vm_fault_badaccess.patch
powerpc-mm-accelerate-pagefault-when-badaccess.patch
riscv-mm-accelerate-pagefault-when-badaccess.patch
riscv-mm-accelerate-pagefault-when-badaccess-fix.patch
s390-mm-accelerate-pagefault-when-badaccess.patch
x86-mm-accelerate-pagefault-when-badaccess.patch
arm64-mm-drop-vm_fault_badmap-vm_fault_badaccess.patch
arm-mm-drop-vm_fault_badmap-vm_fault_badaccess.patch
mm-move-mm-counter-updating-out-of-set_pte_range.patch
mm-filemap-batch-mm-counter-updating-in-filemap_map_pages.patch