diff mbox series

[2/4] mm/filemap: clean up hugetlb exclusion code

Message ID 20240319092733.4501-3-ryncsn@gmail.com (mailing list archive)
State New
Headers show
Series mm/filemap: optimize folio adding and splitting | expand

Commit Message

Kairui Song March 19, 2024, 9:27 a.m. UTC 
From: Kairui Song <kasong@tencent.com>

__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.

Signed-off-by: Kairui Song <kasong@tencent.com>
---
 mm/filemap.c | 21 ++++++++-------------
 1 file changed, 8 insertions(+), 13 deletions(-)

Comments

Matthew Wilcox March 19, 2024, 4:48 p.m. UTC | #1 
On Tue, Mar 19, 2024 at 05:27:31PM +0800, Kairui Song wrote:
> From: Kairui Song <kasong@tencent.com>
> 
> __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.
> 
> Signed-off-by: Kairui Song <kasong@tencent.com>

Ah; excellent.  I once had a patch along these lines, but it never made
it in.  Happy things got refactored to the point where it's now easy,
and mildly annoyed at myself that I hadn't spotted it yet.

Acked-by: Matthew Wilcox (Oracle) <willy@infradead.org>

(I'm acking these on the assumption that Andrew's just going to take
them; I can collect them myself if that makes anybody else's life
easier)
diff mbox series

Patch

diff --git a/mm/filemap.c b/mm/filemap.c
index f07ea0b97698..6bbec8783793 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 @@  noinline int __filemap_add_folio(struct address_space *mapping,
 	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