[PATCH 02/29] mm: vmscan: introduce some helpers for dynamically allocating shrinker

Qi Zheng
2023-06-22T08:40:29Z

From: Qi Zheng <zhengqi.arch@bytedance.com>

Introduce some helpers for dynamically allocating shrinker instance,
and their uses are as follows:

1. shrinker_alloc_and_init()

Used to allocate and initialize a shrinker instance, the priv_data
parameter is used to pass the pointer of the previously embedded
structure of the shrinker instance.

2. shrinker_free()

Used to free the shrinker instance when the registration of shrinker
fails.

3. unregister_and_free_shrinker()

Used to unregister and free the shrinker instance, and the kfree()
will be changed to kfree_rcu() later.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
include/linux/shrinker.h | 12 ++++++++++++
mm/vmscan.c | 35 +++++++++++++++++++++++++++++++++++
2 files changed, 47 insertions(+)

diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h
index 43e6fcabbf51..8e9ba6fa3fcc 100644
--- a/include/linux/shrinker.h
+++ b/include/linux/shrinker.h
@@ -107,6 +107,18 @@ extern void unregister_shrinker(struct shrinker *shrinker);
extern void free_prealloced_shrinker(struct shrinker *shrinker);
extern void synchronize_shrinkers(void);

+typedef unsigned long (*count_objects_cb)(struct shrinker *s,
+ struct shrink_control *sc);
+typedef unsigned long (*scan_objects_cb)(struct shrinker *s,
+ struct shrink_control *sc);
+
+struct shrinker *shrinker_alloc_and_init(count_objects_cb count,
+ scan_objects_cb scan, long batch,
+ int seeks, unsigned flags,
+ void *priv_data);
+void shrinker_free(struct shrinker *shrinker);
+void unregister_and_free_shrinker(struct shrinker *shrinker);
+
#ifdef CONFIG_SHRINKER_DEBUG
extern int shrinker_debugfs_add(struct shrinker *shrinker);
extern struct dentry *shrinker_debugfs_detach(struct shrinker *shrinker,
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 45d17c7cc555..64ff598fbad9 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -809,6 +809,41 @@ void unregister_shrinker(struct shrinker *shrinker)
}
EXPORT_SYMBOL(unregister_shrinker);

+struct shrinker *shrinker_alloc_and_init(count_objects_cb count,
+ scan_objects_cb scan, long batch,
+ int seeks, unsigned flags,
+ void *priv_data)
+{
+ struct shrinker *shrinker;
+
+ shrinker = kzalloc(sizeof(struct shrinker), GFP_KERNEL);
+ if (!shrinker)
+ return NULL;
+
+ shrinker->count_objects = count;
+ shrinker->scan_objects = scan;
+ shrinker->batch = batch;
+ shrinker->seeks = seeks;
+ shrinker->flags = flags;
+ shrinker->private_data = priv_data;
+
+ return shrinker;
+}
+EXPORT_SYMBOL(shrinker_alloc_and_init);
+
+void shrinker_free(struct shrinker *shrinker)
+{
+ kfree(shrinker);
+}
+EXPORT_SYMBOL(shrinker_free);
+
+void unregister_and_free_shrinker(struct shrinker *shrinker)
+{
+ unregister_shrinker(shrinker);
+ kfree(shrinker);
+}
+EXPORT_SYMBOL(unregister_and_free_shrinker);
+
/**
* synchronize_shrinkers - Wait for all running shrinkers to complete.
*
--
2.30.2