[to-be-updated] zsmalloc-add-a-lru-to-zs_pool-to-keep-track-of-zspages-in-lru-order.patch removed from -mm tree

[to-be-updated] zsmalloc-add-a-lru-to-zs_pool-to-keep-track-of-zspages-in-lru-order.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: zsmalloc: add a LRU to zs_pool to keep track of zspages in LRU order
has been removed from the -mm tree.  Its filename was
     zsmalloc-add-a-lru-to-zs_pool-to-keep-track-of-zspages-in-lru-order.patch

This patch was dropped because an updated version will be merged

------------------------------------------------------
From: Nhat Pham <nphamcs@gmail.com>
Subject: zsmalloc: add a LRU to zs_pool to keep track of zspages in LRU order
Date: Wed, 26 Oct 2022 13:06:11 -0700

This helps determines the coldest zspages as candidates for writeback.

Link: https://lkml.kernel.org/r/20221026200613.1031261-4-nphamcs@gmail.com
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 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
@@ -239,6 +239,9 @@ 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
@@ -260,6 +263,10 @@ 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;
@@ -352,6 +359,16 @@ 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)
 {
@@ -953,6 +970,7 @@ static void free_zspage(struct zs_pool *
 	}
 
 	remove_zspage(class, zspage, ZS_EMPTY);
+	list_del(&zspage->lru);
 	__free_zspage(pool, class, zspage);
 }
 
@@ -998,6 +1016,8 @@ static void init_zspage(struct size_clas
 		off %= PAGE_SIZE;
 	}
 
+	INIT_LIST_HEAD(&zspage->lru);
+
 	set_freeobj(zspage, 0);
 }
 
@@ -1418,6 +1438,8 @@ 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;
@@ -1444,6 +1466,8 @@ 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;
@@ -1967,6 +1991,7 @@ 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);
 	}
@@ -2278,6 +2303,8 @@ 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@gmail.com are

zsmalloc-add-ops-fields-to-zs_pool-to-store-evict-handlers.patch
zsmalloc-implement-writeback-mechanism-for-zsmalloc.patch

[to-be-updated] zsmalloc-add-a-lru-to-zs_pool-to-keep-track-of-zspages-in-lru-order.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: zsmalloc: add a LRU to zs_pool to keep track of zspages in LRU order
has been removed from the -mm tree.  Its filename was
     zsmalloc-add-a-lru-to-zs_pool-to-keep-track-of-zspages-in-lru-order.patch

This patch was dropped because an updated version will be merged

------------------------------------------------------
From: Nhat Pham <nphamcs@gmail.com>
Subject: zsmalloc: add a LRU to zs_pool to keep track of zspages in LRU order
Date: Fri, 18 Nov 2022 16:15:34 -0800

This helps determines the coldest zspages as candidates for writeback.

Link: https://lkml.kernel.org/r/20221119001536.2086599-5-nphamcs@gmail.com
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/zsmalloc.c |   50 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

--- a/mm/zsmalloc.c~zsmalloc-add-a-lru-to-zs_pool-to-keep-track-of-zspages-in-lru-order
+++ a/mm/zsmalloc.c
@@ -239,6 +239,11 @@ struct zs_pool {
 	/* Compact classes */
 	struct shrinker shrinker;
 
+#ifdef CONFIG_ZPOOL
+	/* List tracking the zspages in LRU order by most recently added object */
+	struct list_head lru;
+#endif
+
 #ifdef CONFIG_ZSMALLOC_STAT
 	struct dentry *stat_dentry;
 #endif
@@ -260,6 +265,12 @@ struct zspage {
 	unsigned int freeobj;
 	struct page *first_page;
 	struct list_head list; /* fullness list */
+
+#ifdef CONFIG_ZPOOL
+	/* links the zspage to the lru list in the pool */
+	struct list_head lru;
+#endif
+
 	struct zs_pool *pool;
 #ifdef CONFIG_COMPACTION
 	rwlock_t lock;
@@ -953,6 +964,9 @@ static void free_zspage(struct zs_pool *
 	}
 
 	remove_zspage(class, zspage, ZS_EMPTY);
+#ifdef CONFIG_ZPOOL
+	list_del(&zspage->lru);
+#endif
 	__free_zspage(pool, class, zspage);
 }
 
@@ -998,6 +1012,10 @@ static void init_zspage(struct size_clas
 		off %= PAGE_SIZE;
 	}
 
+#ifdef CONFIG_ZPOOL
+	INIT_LIST_HEAD(&zspage->lru);
+#endif
+
 	set_freeobj(zspage, 0);
 }
 
@@ -1270,6 +1288,31 @@ void *zs_map_object(struct zs_pool *pool
 	obj_to_location(obj, &page, &obj_idx);
 	zspage = get_zspage(page);
 
+#ifdef CONFIG_ZPOOL
+	/*
+	 * Move the zspage to front of pool's LRU.
+	 *
+	 * Note that this is swap-specific, so by definition there are no ongoing
+	 * accesses to the memory while the page is swapped out that would make
+	 * it "hot". A new entry is hot, then ages to the tail until it gets either
+	 * written back or swaps back in.
+	 *
+	 * Furthermore, map is also called during writeback. We must not put an
+	 * isolated page on the LRU mid-reclaim.
+	 *
+	 * As a result, only update the LRU when the page is mapped for write
+	 * when it's first instantiated.
+	 *
+	 * This is a deviation from the other backends, which perform this update
+	 * in the allocation function (zbud_alloc, z3fold_alloc).
+	 */
+	if (mm == ZS_MM_WO) {
+		if (!list_empty(&zspage->lru))
+			list_del(&zspage->lru);
+		list_add(&zspage->lru, &pool->lru);
+	}
+#endif
+
 	/*
 	 * migration cannot move any zpages in this zspage. Here, pool->lock
 	 * is too heavy since callers would take some time until they calls
@@ -1988,6 +2031,9 @@ static void async_free_zspage(struct wor
 		VM_BUG_ON(fullness != ZS_EMPTY);
 		class = pool->size_class[class_idx];
 		spin_lock(&pool->lock);
+#ifdef CONFIG_ZPOOL
+		list_del(&zspage->lru);
+#endif
 		__free_zspage(pool, class, zspage);
 		spin_unlock(&pool->lock);
 	}
@@ -2299,6 +2345,10 @@ struct zs_pool *zs_create_pool(const cha
 	 */
 	zs_register_shrinker(pool);
 
+#ifdef CONFIG_ZPOOL
+	INIT_LIST_HEAD(&pool->lru);
+#endif
+
 	return pool;
 
 err:
_

Patches currently in -mm which might be from nphamcs@gmail.com are

zsmalloc-add-zpool_ops-field-to-zs_pool-to-store-evict-handlers.patch
zsmalloc-implement-writeback-mechanism-for-zsmalloc.patch