The patch titled
Subject: zsmalloc: add a LRU to zs_pool to keep track of zspages in LRU order
has been added to the -mm mm-unstable branch. Its filename is
zsmalloc-add-a-lru-to-zs_pool-to-keep-track-of-zspages-in-lru-order.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zsmalloc-add-a-lru-to-zs_pool-to-keep-track-of-zspages-in-lru-order.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: Nhat Pham <nphamcs@xxxxxxxxx>
Subject: zsmalloc: add a LRU to zs_pool to keep track of zspages in LRU order
Date: Tue, 8 Nov 2022 11:32:05 -0800
This helps determines the coldest zspages as candidates for writeback.
Link: https://lkml.kernel.org/r/20221108193207.3297327-4-nphamcs@xxxxxxxxx
Signed-off-by: Nhat Pham <nphamcs@xxxxxxxxx>
Cc: Dan Streetman <ddstreet@xxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Nitin Gupta <ngupta@xxxxxxxxxx>
Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Seth Jennings <sjenning@xxxxxxxxxx>
Cc: Vitaly Wool <vitaly.wool@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/zsmalloc.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
--- a/mm/zsmalloc.c~zsmalloc-add-a-lru-to-zs_pool-to-keep-track-of-zspages-in-lru-order
+++ a/mm/zsmalloc.c
@@ -231,6 +231,9 @@ struct zs_pool {
/* Compact classes */
struct shrinker shrinker;
+ /* List tracking the zspages in LRU order by most recently added object */
+ struct list_head lru;
+
#ifdef CONFIG_ZSMALLOC_STAT
struct dentry *stat_dentry;
#endif
@@ -252,6 +255,10 @@ struct zspage {
unsigned int freeobj;
struct page *first_page;
struct list_head list; /* fullness list */
+
+ /* links the zspage to the lru list in the pool */
+ struct list_head lru;
+
struct zs_pool *pool;
#ifdef CONFIG_COMPACTION
rwlock_t lock;
@@ -344,6 +351,16 @@ static void cache_free_zspage(struct zs_
kmem_cache_free(pool->zspage_cachep, zspage);
}
+/* Moves the zspage to the front of the zspool's LRU */
+static void move_to_front(struct zs_pool *pool, struct zspage *zspage)
+{
+ assert_spin_locked(&pool->lock);
+
+ if (!list_empty(&zspage->lru))
+ list_del(&zspage->lru);
+ list_add(&zspage->lru, &pool->lru);
+}
+
/* pool->lock(which owns the handle) synchronizes races */
static void record_obj(unsigned long handle, unsigned long obj)
{
@@ -948,6 +965,7 @@ static void free_zspage(struct zs_pool *
}
remove_zspage(class, zspage, ZS_EMPTY);
+ list_del(&zspage->lru);
__free_zspage(pool, class, zspage);
}
@@ -993,6 +1011,8 @@ static void init_zspage(struct size_clas
off %= PAGE_SIZE;
}
+ INIT_LIST_HEAD(&zspage->lru);
+
set_freeobj(zspage, 0);
}
@@ -1434,6 +1454,8 @@ unsigned long zs_malloc(struct zs_pool *
fix_fullness_group(class, zspage);
record_obj(handle, obj);
class_stat_inc(class, OBJ_USED, 1);
+ /* Move the zspage to front of pool's LRU */
+ move_to_front(pool, zspage);
spin_unlock(&pool->lock);
return handle;
@@ -1460,6 +1482,8 @@ unsigned long zs_malloc(struct zs_pool *
/* We completely set up zspage so mark them as movable */
SetZsPageMovable(pool, zspage);
+ /* Move the zspage to front of pool's LRU */
+ move_to_front(pool, zspage);
spin_unlock(&pool->lock);
return handle;
@@ -1983,6 +2007,7 @@ static void async_free_zspage(struct wor
VM_BUG_ON(fullness != ZS_EMPTY);
class = pool->size_class[class_idx];
spin_lock(&pool->lock);
+ list_del(&zspage->lru);
__free_zspage(pool, class, zspage);
spin_unlock(&pool->lock);
}
@@ -2313,6 +2338,8 @@ struct zs_pool *zs_create_pool(const cha
*/
zs_register_shrinker(pool);
+ INIT_LIST_HEAD(&pool->lru);
+
return pool;
err:
_
Patches currently in -mm which might be from nphamcs@xxxxxxxxx are
zsmalloc-consolidate-zs_pools-migrate_lock-and-size_classs-locks.patch
zsmalloc-add-a-lru-to-zs_pool-to-keep-track-of-zspages-in-lru-order.patch
zsmalloc-add-ops-fields-to-zs_pool-to-store-evict-handlers.patch
zsmalloc-implement-writeback-mechanism-for-zsmalloc.patch
