+ mm-swap-make-should_try_to_free_swap-support-large-folio.patch added to mm-unstable branch

+ mm-swap-make-should_try_to_free_swap-support-large-folio.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm: swap: make should_try_to_free_swap() support large-folio
has been added to the -mm mm-unstable branch.  Its filename is
     mm-swap-make-should_try_to_free_swap-support-large-folio.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-swap-make-should_try_to_free_swap-support-large-folio.patch

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

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------------------------------------------------------
From: Chuanhua Han <hanchuanhua@oppo.com>
Subject: mm: swap: make should_try_to_free_swap() support large-folio
Date: Tue, 9 Apr 2024 20:26:28 +1200

The function should_try_to_free_swap() operates under the assumption that
swap-in always occurs at the normal page granularity, i.e., folio_nr_pages
= 1.  However, in reality, for large folios, add_to_swap_cache() will
invoke folio_ref_add(folio, nr).  To accommodate large folio swap-in, this
patch eliminates this assumption.

Link: https://lkml.kernel.org/r/20240409082631.187483-3-21cnbao@gmail.com
Signed-off-by: Chuanhua Han <hanchuanhua@oppo.com>
Co-developed-by: Barry Song <v-songbaohua@oppo.com>
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Acked-by: Chris Li <chrisl@kernel.org>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gao Xiang <xiang@kernel.org>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memory.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/memory.c~mm-swap-make-should_try_to_free_swap-support-large-folio
+++ a/mm/memory.c
@@ -3853,7 +3853,7 @@ static inline bool should_try_to_free_sw
 	 * reference only in case it's likely that we'll be the exlusive user.
 	 */
 	return (fault_flags & FAULT_FLAG_WRITE) && !folio_test_ksm(folio) &&
-		folio_ref_count(folio) == 2;
+		folio_ref_count(folio) == (1 + folio_nr_pages(folio));
 }
 
 static vm_fault_t pte_marker_clear(struct vm_fault *vmf)
_

Patches currently in -mm which might be from hanchuanhua@oppo.com are

mm-swap-introduce-swap_free_nr-for-batched-swap_free.patch
mm-swap-make-should_try_to_free_swap-support-large-folio.patch
mm-swap-entirely-map-large-folios-found-in-swapcache.patch