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From eca3858631e0cbad2ca6e40f788892749428e4cb Mon Sep 17 00:00:00 2001
From: Yu Zhao <yuzhao@google.com>
Date: Wed, 21 Dec 2022 21:19:03 -0700
Subject: [PATCH 05/19] UPSTREAM: mm: multi-gen LRU: shuffle should_run_aging()

Move should_run_aging() next to its only caller left.

Link: https://lkml.kernel.org/r/20221222041905.2431096-6-yuzhao@google.com
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michael Larabel <Michael@MichaelLarabel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Bug: 274865848
(cherry picked from commit 77d4459a4a1a472b7309e475f962dda87d950abd)
Signed-off-by: T.J. Mercier <tjmercier@google.com>
Change-Id: I3b0383fe16b93a783b4d8c0b3a0b325160392576
Signed-off-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: T.J. Mercier <tjmercier@google.com>
---
 mm/vmscan.c | 124 ++++++++++++++++++++++++++--------------------------
 1 file changed, 62 insertions(+), 62 deletions(-)

--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4454,68 +4454,6 @@ done:
        return true;
 }
 
-static bool should_run_aging(struct lruvec *lruvec, unsigned long max_seq,
-                            struct scan_control *sc, bool can_swap, unsigned long *nr_to_scan)
-{
-       int gen, type, zone;
-       unsigned long old = 0;
-       unsigned long young = 0;
-       unsigned long total = 0;
-       struct lru_gen_folio *lrugen = &lruvec->lrugen;
-       struct mem_cgroup *memcg = lruvec_memcg(lruvec);
-       DEFINE_MIN_SEQ(lruvec);
-
-       /* whether this lruvec is completely out of cold folios */
-       if (min_seq[!can_swap] + MIN_NR_GENS > max_seq) {
-               *nr_to_scan = 0;
-               return true;
-       }
-
-       for (type = !can_swap; type < ANON_AND_FILE; type++) {
-               unsigned long seq;
-
-               for (seq = min_seq[type]; seq <= max_seq; seq++) {
-                       unsigned long size = 0;
-
-                       gen = lru_gen_from_seq(seq);
-
-                       for (zone = 0; zone < MAX_NR_ZONES; zone++)
-                               size += max(READ_ONCE(lrugen->nr_pages[gen][type][zone]), 0L);
-
-                       total += size;
-                       if (seq == max_seq)
-                               young += size;
-                       else if (seq + MIN_NR_GENS == max_seq)
-                               old += size;
-               }
-       }
-
-       /* try to scrape all its memory if this memcg was deleted */
-       *nr_to_scan = mem_cgroup_online(memcg) ? (total >> sc->priority) : total;
-
-       /*
-        * The aging tries to be lazy to reduce the overhead, while the eviction
-        * stalls when the number of generations reaches MIN_NR_GENS. Hence, the
-        * ideal number of generations is MIN_NR_GENS+1.
-        */
-       if (min_seq[!can_swap] + MIN_NR_GENS < max_seq)
-               return false;
-
-       /*
-        * It's also ideal to spread pages out evenly, i.e., 1/(MIN_NR_GENS+1)
-        * of the total number of pages for each generation. A reasonable range
-        * for this average portion is [1/MIN_NR_GENS, 1/(MIN_NR_GENS+2)]. The
-        * aging cares about the upper bound of hot pages, while the eviction
-        * cares about the lower bound of cold pages.
-        */
-       if (young * MIN_NR_GENS > total)
-               return true;
-       if (old * (MIN_NR_GENS + 2) < total)
-               return true;
-
-       return false;
-}
-
 static bool lruvec_is_sizable(struct lruvec *lruvec, struct scan_control *sc)
 {
        int gen, type, zone;
@@ -5099,6 +5037,68 @@ retry:
        return scanned;
 }
 
+static bool should_run_aging(struct lruvec *lruvec, unsigned long max_seq,
+                            struct scan_control *sc, bool can_swap, unsigned long *nr_to_scan)
+{
+       int gen, type, zone;
+       unsigned long old = 0;
+       unsigned long young = 0;
+       unsigned long total = 0;
+       struct lru_gen_folio *lrugen = &lruvec->lrugen;
+       struct mem_cgroup *memcg = lruvec_memcg(lruvec);
+       DEFINE_MIN_SEQ(lruvec);
+
+       /* whether this lruvec is completely out of cold folios */
+       if (min_seq[!can_swap] + MIN_NR_GENS > max_seq) {
+               *nr_to_scan = 0;
+               return true;
+       }
+
+       for (type = !can_swap; type < ANON_AND_FILE; type++) {
+               unsigned long seq;
+
+               for (seq = min_seq[type]; seq <= max_seq; seq++) {
+                       unsigned long size = 0;
+
+                       gen = lru_gen_from_seq(seq);
+
+                       for (zone = 0; zone < MAX_NR_ZONES; zone++)
+                               size += max(READ_ONCE(lrugen->nr_pages[gen][type][zone]), 0L);
+
+                       total += size;
+                       if (seq == max_seq)
+                               young += size;
+                       else if (seq + MIN_NR_GENS == max_seq)
+                               old += size;
+               }
+       }
+
+       /* try to scrape all its memory if this memcg was deleted */
+       *nr_to_scan = mem_cgroup_online(memcg) ? (total >> sc->priority) : total;
+
+       /*
+        * The aging tries to be lazy to reduce the overhead, while the eviction
+        * stalls when the number of generations reaches MIN_NR_GENS. Hence, the
+        * ideal number of generations is MIN_NR_GENS+1.
+        */
+       if (min_seq[!can_swap] + MIN_NR_GENS < max_seq)
+               return false;
+
+       /*
+        * It's also ideal to spread pages out evenly, i.e., 1/(MIN_NR_GENS+1)
+        * of the total number of pages for each generation. A reasonable range
+        * for this average portion is [1/MIN_NR_GENS, 1/(MIN_NR_GENS+2)]. The
+        * aging cares about the upper bound of hot pages, while the eviction
+        * cares about the lower bound of cold pages.
+        */
+       if (young * MIN_NR_GENS > total)
+               return true;
+       if (old * (MIN_NR_GENS + 2) < total)
+               return true;
+
+       return false;
+}
+
 /*
  * For future optimizations:
  * 1. Defer try_to_inc_max_seq() to workqueues to reduce latency for memcg