linux-kernel - [PATCH v8 2/3] mm: add nr argument in mem_cgroup_swapin_uncharge

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Message-Id: <20240906001047.1245-3-21cnbao@gmail.com>
Date: Fri,  6 Sep 2024 12:10:46 +1200
From: Barry Song <21cnbao@...il.com>
To: akpm@...ux-foundation.org,
	linux-mm@...ck.org
Cc: hanchuanhua@...o.com,
	baolin.wang@...ux.alibaba.com,
	chrisl@...nel.org,
	david@...hat.com,
	hannes@...xchg.org,
	hch@...radead.org,
	hughd@...gle.com,
	kaleshsingh@...gle.com,
	kasong@...cent.com,
	linux-kernel@...r.kernel.org,
	mhocko@...e.com,
	minchan@...nel.org,
	nphamcs@...il.com,
	ryan.roberts@....com,
	ryncsn@...il.com,
	senozhatsky@...omium.org,
	shakeel.butt@...ux.dev,
	shy828301@...il.com,
	surenb@...gle.com,
	v-songbaohua@...o.com,
	willy@...radead.org,
	xiang@...nel.org,
	ying.huang@...el.com,
	yosryahmed@...gle.com
Subject: [PATCH v8 2/3] mm: add nr argument in mem_cgroup_swapin_uncharge_swap() helper to support large folios

From: Barry Song <v-songbaohua@...o.com>

With large folios swap-in, we might need to uncharge multiple entries all
together, add nr argument in mem_cgroup_swapin_uncharge_swap().

For the existing two users, just pass nr=1.

Signed-off-by: Barry Song <v-songbaohua@...o.com>
Acked-by: Chris Li <chrisl@...nel.org>
Cc: Shakeel Butt <shakeel.butt@...ux.dev>
Cc: Baolin Wang <baolin.wang@...ux.alibaba.com>
Cc: Christoph Hellwig <hch@...radead.org>
Cc: David Hildenbrand <david@...hat.com>
Cc: Gao Xiang <xiang@...nel.org>
Cc: "Huang, Ying" <ying.huang@...el.com>
Cc: Hugh Dickins <hughd@...gle.com>
Cc: Johannes Weiner <hannes@...xchg.org>
Cc: Kairui Song <kasong@...cent.com>
Cc: Kairui Song <ryncsn@...il.com>
Cc: Kalesh Singh <kaleshsingh@...gle.com>
Cc: Matthew Wilcox (Oracle) <willy@...radead.org>
Cc: Michal Hocko <mhocko@...e.com>
Cc: Minchan Kim <minchan@...nel.org>
Cc: Nhat Pham <nphamcs@...il.com>
Cc: Ryan Roberts <ryan.roberts@....com>
Cc: Sergey Senozhatsky <senozhatsky@...omium.org>
Cc: Suren Baghdasaryan <surenb@...gle.com>
Cc: Yang Shi <shy828301@...il.com>
Cc: Yosry Ahmed <yosryahmed@...gle.com>
---
 include/linux/memcontrol.h | 5 +++--
 mm/memcontrol.c            | 7 ++++---
 mm/memory.c                | 2 +-
 mm/swap_state.c            | 2 +-
 4 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 2ef94c74847d..34d2da05f2f1 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -699,7 +699,8 @@ int mem_cgroup_hugetlb_try_charge(struct mem_cgroup *memcg, gfp_t gfp,
 
 int mem_cgroup_swapin_charge_folio(struct folio *folio, struct mm_struct *mm,
 				  gfp_t gfp, swp_entry_t entry);
-void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry);
+
+void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry, unsigned int nr_pages);
 
 void __mem_cgroup_uncharge(struct folio *folio);
 
@@ -1206,7 +1207,7 @@ static inline int mem_cgroup_swapin_charge_folio(struct folio *folio,
 	return 0;
 }
 
-static inline void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry)
+static inline void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry, unsigned int nr)
 {
 }
 
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index bda6f75d22ff..c0d36ca20332 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4559,14 +4559,15 @@ int mem_cgroup_swapin_charge_folio(struct folio *folio, struct mm_struct *mm,
 
 /*
  * mem_cgroup_swapin_uncharge_swap - uncharge swap slot
- * @entry: swap entry for which the page is charged
+ * @entry: the first swap entry for which the pages are charged
+ * @nr_pages: number of pages which will be uncharged
  *
  * Call this function after successfully adding the charged page to swapcache.
  *
  * Note: This function assumes the page for which swap slot is being uncharged
  * is order 0 page.
  */
-void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry)
+void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
 {
 	/*
 	 * Cgroup1's unified memory+swap counter has been charged with the
@@ -4586,7 +4587,7 @@ void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry)
 		 * let's not wait for it.  The page already received a
 		 * memory+swap charge, drop the swap entry duplicate.
 		 */
-		mem_cgroup_uncharge_swap(entry, 1);
+		mem_cgroup_uncharge_swap(entry, nr_pages);
 	}
 }
 
diff --git a/mm/memory.c b/mm/memory.c
index 42674c0748cb..cdf03b39a92c 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4100,7 +4100,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
 					ret = VM_FAULT_OOM;
 					goto out_page;
 				}
-				mem_cgroup_swapin_uncharge_swap(entry);
+				mem_cgroup_swapin_uncharge_swap(entry, 1);
 
 				shadow = get_shadow_from_swap_cache(entry);
 				if (shadow)
diff --git a/mm/swap_state.c b/mm/swap_state.c
index a042720554a7..4669f29cf555 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -522,7 +522,7 @@ struct folio *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
 	if (add_to_swap_cache(new_folio, entry, gfp_mask & GFP_RECLAIM_MASK, &shadow))
 		goto fail_unlock;
 
-	mem_cgroup_swapin_uncharge_swap(entry);
+	mem_cgroup_swapin_uncharge_swap(entry, 1);
 
 	if (shadow)
 		workingset_refault(new_folio, shadow);
-- 
2.34.1