The patch titled
Subject: mm/vmscan.c: refactor shrink_node()
has been added to the -mm mm-unstable branch. Its filename is
mm-vmscanc-refactor-shrink_node.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmscanc-refactor-shrink_node.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: Yu Zhao <yuzhao@xxxxxxxxxx>
Subject: mm/vmscan.c: refactor shrink_node()
Date: Mon, 15 Aug 2022 01:13:22 -0600
This patch refactors shrink_node() to improve readability for the upcoming
changes to mm/vmscan.c.
Link: https://lkml.kernel.org/r/20220815071332.627393-4-yuzhao@xxxxxxxxxx
Signed-off-by: Yu Zhao <yuzhao@xxxxxxxxxx>
Reviewed-by: Barry Song <baohua@xxxxxxxxxx>
Reviewed-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Acked-by: Brian Geffon <bgeffon@xxxxxxxxxx>
Acked-by: Jan Alexander Steffens (heftig) <heftig@xxxxxxxxxxxxx>
Acked-by: Oleksandr Natalenko <oleksandr@xxxxxxxxxxxxxx>
Acked-by: Steven Barrett <steven@xxxxxxxxxxxx>
Acked-by: Suleiman Souhlal <suleiman@xxxxxxxxxx>
Tested-by: Daniel Byrne <djbyrne@xxxxxxx>
Tested-by: Donald Carr <d@xxxxxxxxxxxxxxx>
Tested-by: Holger Hoffstätte <holger@xxxxxxxxxxxxxxxxxxxxxx>
Tested-by: Konstantin Kharlamov <Hi-Angel@xxxxxxxxx>
Tested-by: Shuang Zhai <szhai2@xxxxxxxxxxxxxxxx>
Tested-by: Sofia Trinh <sofia.trinh@edi.works>
Tested-by: Vaibhav Jain <vaibhav@xxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Hillf Danton <hdanton@xxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Michael Larabel <Michael@xxxxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 198 ++++++++++++++++++++++++++------------------------
1 file changed, 104 insertions(+), 94 deletions(-)
--- a/mm/vmscan.c~mm-vmscanc-refactor-shrink_node
+++ a/mm/vmscan.c
@@ -2728,6 +2728,109 @@ enum scan_balance {
SCAN_FILE,
};
+static void prepare_scan_count(pg_data_t *pgdat, struct scan_control *sc)
+{
+ unsigned long file;
+ struct lruvec *target_lruvec;
+
+ target_lruvec = mem_cgroup_lruvec(sc->target_mem_cgroup, pgdat);
+
+ /*
+ * Flush the memory cgroup stats, so that we read accurate per-memcg
+ * lruvec stats for heuristics.
+ */
+ mem_cgroup_flush_stats();
+
+ /*
+ * Determine the scan balance between anon and file LRUs.
+ */
+ spin_lock_irq(&target_lruvec->lru_lock);
+ sc->anon_cost = target_lruvec->anon_cost;
+ sc->file_cost = target_lruvec->file_cost;
+ spin_unlock_irq(&target_lruvec->lru_lock);
+
+ /*
+ * Target desirable inactive:active list ratios for the anon
+ * and file LRU lists.
+ */
+ if (!sc->force_deactivate) {
+ unsigned long refaults;
+
+ /*
+ * When refaults are being observed, it means a new
+ * workingset is being established. Deactivate to get
+ * rid of any stale active pages quickly.
+ */
+ refaults = lruvec_page_state(target_lruvec,
+ WORKINGSET_ACTIVATE_ANON);
+ if (refaults != target_lruvec->refaults[WORKINGSET_ANON] ||
+ inactive_is_low(target_lruvec, LRU_INACTIVE_ANON))
+ sc->may_deactivate |= DEACTIVATE_ANON;
+ else
+ sc->may_deactivate &= ~DEACTIVATE_ANON;
+
+ refaults = lruvec_page_state(target_lruvec,
+ WORKINGSET_ACTIVATE_FILE);
+ if (refaults != target_lruvec->refaults[WORKINGSET_FILE] ||
+ inactive_is_low(target_lruvec, LRU_INACTIVE_FILE))
+ sc->may_deactivate |= DEACTIVATE_FILE;
+ else
+ sc->may_deactivate &= ~DEACTIVATE_FILE;
+ } else
+ sc->may_deactivate = DEACTIVATE_ANON | DEACTIVATE_FILE;
+
+ /*
+ * If we have plenty of inactive file pages that aren't
+ * thrashing, try to reclaim those first before touching
+ * anonymous pages.
+ */
+ file = lruvec_page_state(target_lruvec, NR_INACTIVE_FILE);
+ if (file >> sc->priority && !(sc->may_deactivate & DEACTIVATE_FILE))
+ sc->cache_trim_mode = 1;
+ else
+ sc->cache_trim_mode = 0;
+
+ /*
+ * Prevent the reclaimer from falling into the cache trap: as
+ * cache pages start out inactive, every cache fault will tip
+ * the scan balance towards the file LRU. And as the file LRU
+ * shrinks, so does the window for rotation from references.
+ * This means we have a runaway feedback loop where a tiny
+ * thrashing file LRU becomes infinitely more attractive than
+ * anon pages. Try to detect this based on file LRU size.
+ */
+ if (!cgroup_reclaim(sc)) {
+ unsigned long total_high_wmark = 0;
+ unsigned long free, anon;
+ int z;
+
+ free = sum_zone_node_page_state(pgdat->node_id, NR_FREE_PAGES);
+ file = node_page_state(pgdat, NR_ACTIVE_FILE) +
+ node_page_state(pgdat, NR_INACTIVE_FILE);
+
+ for (z = 0; z < MAX_NR_ZONES; z++) {
+ struct zone *zone = &pgdat->node_zones[z];
+
+ if (!managed_zone(zone))
+ continue;
+
+ total_high_wmark += high_wmark_pages(zone);
+ }
+
+ /*
+ * Consider anon: if that's low too, this isn't a
+ * runaway file reclaim problem, but rather just
+ * extreme pressure. Reclaim as per usual then.
+ */
+ anon = node_page_state(pgdat, NR_INACTIVE_ANON);
+
+ sc->file_is_tiny =
+ file + free <= total_high_wmark &&
+ !(sc->may_deactivate & DEACTIVATE_ANON) &&
+ anon >> sc->priority;
+ }
+}
+
/*
* Determine how aggressively the anon and file LRU lists should be
* scanned.
@@ -3195,109 +3298,16 @@ static void shrink_node(pg_data_t *pgdat
unsigned long nr_reclaimed, nr_scanned;
struct lruvec *target_lruvec;
bool reclaimable = false;
- unsigned long file;
target_lruvec = mem_cgroup_lruvec(sc->target_mem_cgroup, pgdat);
again:
- /*
- * Flush the memory cgroup stats, so that we read accurate per-memcg
- * lruvec stats for heuristics.
- */
- mem_cgroup_flush_stats();
-
memset(&sc->nr, 0, sizeof(sc->nr));
nr_reclaimed = sc->nr_reclaimed;
nr_scanned = sc->nr_scanned;
- /*
- * Determine the scan balance between anon and file LRUs.
- */
- spin_lock_irq(&target_lruvec->lru_lock);
- sc->anon_cost = target_lruvec->anon_cost;
- sc->file_cost = target_lruvec->file_cost;
- spin_unlock_irq(&target_lruvec->lru_lock);
-
- /*
- * Target desirable inactive:active list ratios for the anon
- * and file LRU lists.
- */
- if (!sc->force_deactivate) {
- unsigned long refaults;
-
- /*
- * When refaults are being observed, it means a new
- * workingset is being established. Deactivate to get
- * rid of any stale active pages quickly.
- */
- refaults = lruvec_page_state(target_lruvec,
- WORKINGSET_ACTIVATE_ANON);
- if (refaults != target_lruvec->refaults[WORKINGSET_ANON] ||
- inactive_is_low(target_lruvec, LRU_INACTIVE_ANON))
- sc->may_deactivate |= DEACTIVATE_ANON;
- else
- sc->may_deactivate &= ~DEACTIVATE_ANON;
-
- refaults = lruvec_page_state(target_lruvec,
- WORKINGSET_ACTIVATE_FILE);
- if (refaults != target_lruvec->refaults[WORKINGSET_FILE] ||
- inactive_is_low(target_lruvec, LRU_INACTIVE_FILE))
- sc->may_deactivate |= DEACTIVATE_FILE;
- else
- sc->may_deactivate &= ~DEACTIVATE_FILE;
- } else
- sc->may_deactivate = DEACTIVATE_ANON | DEACTIVATE_FILE;
-
- /*
- * If we have plenty of inactive file pages that aren't
- * thrashing, try to reclaim those first before touching
- * anonymous pages.
- */
- file = lruvec_page_state(target_lruvec, NR_INACTIVE_FILE);
- if (file >> sc->priority && !(sc->may_deactivate & DEACTIVATE_FILE))
- sc->cache_trim_mode = 1;
- else
- sc->cache_trim_mode = 0;
-
- /*
- * Prevent the reclaimer from falling into the cache trap: as
- * cache pages start out inactive, every cache fault will tip
- * the scan balance towards the file LRU. And as the file LRU
- * shrinks, so does the window for rotation from references.
- * This means we have a runaway feedback loop where a tiny
- * thrashing file LRU becomes infinitely more attractive than
- * anon pages. Try to detect this based on file LRU size.
- */
- if (!cgroup_reclaim(sc)) {
- unsigned long total_high_wmark = 0;
- unsigned long free, anon;
- int z;
-
- free = sum_zone_node_page_state(pgdat->node_id, NR_FREE_PAGES);
- file = node_page_state(pgdat, NR_ACTIVE_FILE) +
- node_page_state(pgdat, NR_INACTIVE_FILE);
-
- for (z = 0; z < MAX_NR_ZONES; z++) {
- struct zone *zone = &pgdat->node_zones[z];
- if (!managed_zone(zone))
- continue;
-
- total_high_wmark += high_wmark_pages(zone);
- }
-
- /*
- * Consider anon: if that's low too, this isn't a
- * runaway file reclaim problem, but rather just
- * extreme pressure. Reclaim as per usual then.
- */
- anon = node_page_state(pgdat, NR_INACTIVE_ANON);
-
- sc->file_is_tiny =
- file + free <= total_high_wmark &&
- !(sc->may_deactivate & DEACTIVATE_ANON) &&
- anon >> sc->priority;
- }
+ prepare_scan_count(pgdat, sc);
shrink_node_memcgs(pgdat, sc);
_
Patches currently in -mm which might be from yuzhao@xxxxxxxxxx are
mm-x86-arm64-add-arch_has_hw_pte_young.patch
mm-x86-add-config_arch_has_nonleaf_pmd_young.patch
mm-vmscanc-refactor-shrink_node.patch
revert-include-linux-mm_inlineh-fold-__update_lru_size-into-its-sole-caller.patch
mm-multi-gen-lru-groundwork.patch
mm-multi-gen-lru-minimal-implementation.patch
mm-multi-gen-lru-exploit-locality-in-rmap.patch
mm-multi-gen-lru-support-page-table-walks.patch
mm-multi-gen-lru-optimize-multiple-memcgs.patch
mm-multi-gen-lru-kill-switch.patch
mm-multi-gen-lru-thrashing-prevention.patch
mm-multi-gen-lru-debugfs-interface.patch
mm-multi-gen-lru-admin-guide.patch
mm-multi-gen-lru-design-doc.patch
