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From:   Nhat Pham <nphamcs@gmail.com>
To:     akpm@linux-foundation.org
Cc:     hannes@cmpxchg.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, minchan@kernel.org,
        ngupta@vflare.org, senozhatsky@chromium.org, sjenning@redhat.com,
        ddstreet@ieee.org, vitaly.wool@konsulko.com
Subject: [PATCH v3 4/5] zsmalloc: Add ops fields to zs_pool to store evict handlers
Date:   Tue,  8 Nov 2022 11:32:06 -0800
Message-Id: <20221108193207.3297327-5-nphamcs@gmail.com>
In-Reply-To: <20221108193207.3297327-1-nphamcs@gmail.com>
References: <20221108193207.3297327-1-nphamcs@gmail.com>
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This adds fields to zs_pool to store evict handlers for writeback,
analogous to the zbud allocator.

Signed-off-by: Nhat Pham <nphamcs@gmail.com>
---
 mm/zsmalloc.c | 38 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 37 insertions(+), 1 deletion(-)

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 600c40121544..ac86cffa62cd 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -225,6 +225,12 @@ struct link_free {
 	};
 };

+struct zs_pool;
+
+struct zs_ops {
+	int (*evict)(struct zs_pool *pool, unsigned long handle);
+};
+
 struct zs_pool {
 	const char *name;

@@ -242,6 +248,12 @@ struct zs_pool {
 	/* List tracking the zspages in LRU order by most recently added object */
 	struct list_head lru;

+#ifdef CONFIG_ZPOOL
+	const struct zs_ops *ops;
+	struct zpool *zpool;
+	const struct zpool_ops *zpool_ops;
+#endif
+
 #ifdef CONFIG_ZSMALLOC_STAT
 	struct dentry *stat_dentry;
 #endif
@@ -379,6 +391,18 @@ static void record_obj(unsigned long handle, unsigned long obj)

 #ifdef CONFIG_ZPOOL

+static int zs_zpool_evict(struct zs_pool *pool, unsigned long handle)
+{
+	if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict)
+		return pool->zpool_ops->evict(pool->zpool, handle);
+	else
+		return -ENOENT;
+}
+
+static const struct zs_ops zs_zpool_ops = {
+	.evict =	zs_zpool_evict
+};
+
 static void *zs_zpool_create(const char *name, gfp_t gfp,
 			     const struct zpool_ops *zpool_ops,
 			     struct zpool *zpool)
@@ -388,7 +412,19 @@ static void *zs_zpool_create(const char *name, gfp_t gfp,
 	 * different contexts and its caller must provide a valid
 	 * gfp mask.
 	 */
-	return zs_create_pool(name);
+	struct zs_pool *pool = zs_create_pool(name);
+
+	if (pool) {
+		pool->zpool = zpool;
+		pool->zpool_ops = zpool_ops;
+
+		if (zpool_ops)
+			pool->ops = &zs_zpool_ops;
+		else
+			pool->ops = NULL;
+	}
+
+	return pool;
 }

 static void zs_zpool_destroy(void *pool)
--
2.30.2