[merged mm-stable] mm-swap-dont-update-the-counter-up-front.patch removed from -mm tree

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

The quilt patch titled
     Subject: mm, swap: don't update the counter up-front
has been removed from the -mm tree.  Its filename was
     mm-swap-dont-update-the-counter-up-front.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Kairui Song <kasong@tencent.com>
Subject: mm, swap: don't update the counter up-front
Date: Fri, 14 Mar 2025 00:59:32 +0800

The counter update before allocation design was useful to avoid
unnecessary scan when device is full, so it will abort early if the
counter indicates the device is full.  But that is an uncommon case, and
now scanning of a full device is very fast, so the up-front update is not
helpful any more.

Remove it and simplify the slot allocation logic.

Link: https://lkml.kernel.org/r/20250313165935.63303-5-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/swapfile.c |   18 ++----------------
 1 file changed, 2 insertions(+), 16 deletions(-)

--- a/mm/swapfile.c~mm-swap-dont-update-the-counter-up-front
+++ a/mm/swapfile.c
@@ -1201,22 +1201,10 @@ int get_swap_pages(int n_goal, swp_entry
 	int order = swap_entry_order(entry_order);
 	unsigned long size = 1 << order;
 	struct swap_info_struct *si, *next;
-	long avail_pgs;
 	int n_ret = 0;
 	int node;
 
 	spin_lock(&swap_avail_lock);
-
-	avail_pgs = atomic_long_read(&nr_swap_pages) / size;
-	if (avail_pgs <= 0) {
-		spin_unlock(&swap_avail_lock);
-		goto noswap;
-	}
-
-	n_goal = min3((long)n_goal, (long)SWAP_BATCH, avail_pgs);
-
-	atomic_long_sub(n_goal * size, &nr_swap_pages);
-
 start_over:
 	node = numa_node_id();
 	plist_for_each_entry_safe(si, next, &swap_avail_heads[node], avail_lists[node]) {
@@ -1250,10 +1238,8 @@ start_over:
 	spin_unlock(&swap_avail_lock);
 
 check_out:
-	if (n_ret < n_goal)
-		atomic_long_add((long)(n_goal - n_ret) * size,
-				&nr_swap_pages);
-noswap:
+	atomic_long_sub(n_ret * size, &nr_swap_pages);
+
 	return n_ret;
 }
 
_

Patches currently in -mm which might be from kasong@tencent.com are