From: Kairui Song <kasong@tencent.com>
Date: Mon, 15 Apr 2024 17:18:54 +0000 (+0800)
Subject: mm/filemap: clean up hugetlb exclusion code
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=b2ebcf9d3d5a0108f640d8c8200ece8848045725;p=linux.git

mm/filemap: clean up hugetlb exclusion code

__filemap_add_folio only has two callers, one never passes hugetlb folio
and one always passes in hugetlb folio.  So move the hugetlb related
cgroup charging out of it to make the code cleaner.

Link: https://lkml.kernel.org/r/20240415171857.19244-3-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Acked-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/filemap.c b/mm/filemap.c
index 12089c24abfbd..17a66ea544e71 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -853,20 +853,12 @@ noinline int __filemap_add_folio(struct address_space *mapping,
 {
 	XA_STATE(xas, &mapping->i_pages, index);
 	bool huge = folio_test_hugetlb(folio);
-	bool charged = false;
-	long nr = 1;
+	long nr;
 
 	VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
 	VM_BUG_ON_FOLIO(folio_test_swapbacked(folio), folio);
 	mapping_set_update(&xas, mapping);
 
-	if (!huge) {
-		int error = mem_cgroup_charge(folio, NULL, gfp);
-		if (error)
-			return error;
-		charged = true;
-	}
-
 	VM_BUG_ON_FOLIO(index & (folio_nr_pages(folio) - 1), folio);
 	xas_set_order(&xas, index, folio_order(folio));
 	nr = folio_nr_pages(folio);
@@ -931,8 +923,6 @@ unlock:
 	trace_mm_filemap_add_to_page_cache(folio);
 	return 0;
 error:
-	if (charged)
-		mem_cgroup_uncharge(folio);
 	folio->mapping = NULL;
 	/* Leave page->index set: truncation relies upon it */
 	folio_put_refs(folio, nr);
@@ -946,11 +936,16 @@ int filemap_add_folio(struct address_space *mapping, struct folio *folio,
 	void *shadow = NULL;
 	int ret;
 
+	ret = mem_cgroup_charge(folio, NULL, gfp);
+	if (ret)
+		return ret;
+
 	__folio_set_locked(folio);
 	ret = __filemap_add_folio(mapping, folio, index, gfp, &shadow);
-	if (unlikely(ret))
+	if (unlikely(ret)) {
+		mem_cgroup_uncharge(folio);
 		__folio_clear_locked(folio);
-	else {
+	} else {
 		/*
 		 * The folio might have been evicted from cache only
 		 * recently, in which case it should be activated like