On 2023/7/26 15:10, Muchun Song wrote:

On 2023/7/24 17:43, Qi Zheng wrote:

quoted

Use new APIs to dynamically allocate the thp-zero and thp-deferred_split
shrinkers.

Signed-off-by: Qi Zheng <redacted>
---
  mm/huge_memory.c | 69 +++++++++++++++++++++++++++++++-----------------
  1 file changed, 45 insertions(+), 24 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 8c94b34024a2..4db5a1834d81 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c

@@ -65,7 +65,11 @@ unsigned long transparent_hugepage_flags 

__read_mostly =
      (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)|
      (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
-static struct shrinker deferred_split_shrinker;
+static struct shrinker *deferred_split_shrinker;
+static unsigned long deferred_split_count(struct shrinker *shrink,
+                      struct shrink_control *sc);
+static unsigned long deferred_split_scan(struct shrinker *shrink,
+                     struct shrink_control *sc);
  static atomic_t huge_zero_refcount;
  struct page *huge_zero_page __read_mostly;

@@ -229,11 +233,7 @@ static unsigned long 

shrink_huge_zero_page_scan(struct shrinker *shrink,
      return 0;
  }
-static struct shrinker huge_zero_page_shrinker = {
-    .count_objects = shrink_huge_zero_page_count,
-    .scan_objects = shrink_huge_zero_page_scan,
-    .seeks = DEFAULT_SEEKS,
-};
+static struct shrinker *huge_zero_page_shrinker;

Same as patch #17.

OK, will do.

quoted

  #ifdef CONFIG_SYSFS
  static ssize_t enabled_show(struct kobject *kobj,

@@ -454,6 +454,40 @@ static inline void hugepage_exit_sysfs(struct 

kobject *hugepage_kobj)
  }
  #endif /* CONFIG_SYSFS */
+static int thp_shrinker_init(void)

Better to declare it as __init.

Will do.

quoted

+{
+    huge_zero_page_shrinker = shrinker_alloc(0, "thp-zero");
+    if (!huge_zero_page_shrinker)
+        return -ENOMEM;
+
+    deferred_split_shrinker = shrinker_alloc(SHRINKER_NUMA_AWARE |
+                         SHRINKER_MEMCG_AWARE |
+                         SHRINKER_NONSLAB,
+                         "thp-deferred_split");
+    if (!deferred_split_shrinker) {
+        shrinker_free_non_registered(huge_zero_page_shrinker);
+        return -ENOMEM;
+    }
+
+    huge_zero_page_shrinker->count_objects = 
shrink_huge_zero_page_count;
+    huge_zero_page_shrinker->scan_objects = shrink_huge_zero_page_scan;
+    huge_zero_page_shrinker->seeks = DEFAULT_SEEKS;
+    shrinker_register(huge_zero_page_shrinker);
+
+    deferred_split_shrinker->count_objects = deferred_split_count;
+    deferred_split_shrinker->scan_objects = deferred_split_scan;
+    deferred_split_shrinker->seeks = DEFAULT_SEEKS;
+    shrinker_register(deferred_split_shrinker);
+
+    return 0;
+}
+
+static void thp_shrinker_exit(void)

Same as here.

Will do.

quoted

+{
+    shrinker_unregister(huge_zero_page_shrinker);
+    shrinker_unregister(deferred_split_shrinker);
+}
+
  static int __init hugepage_init(void)
  {
      int err;

@@ -482,12 +516,9 @@ static int __init hugepage_init(void)

      if (err)
          goto err_slab;
-    err = register_shrinker(&huge_zero_page_shrinker, "thp-zero");
-    if (err)
-        goto err_hzp_shrinker;
-    err = register_shrinker(&deferred_split_shrinker, 
"thp-deferred_split");
+    err = thp_shrinker_init();
      if (err)
-        goto err_split_shrinker;
+        goto err_shrinker;
      /*
       * By default disable transparent hugepages on smaller systems,

@@ -505,10 +536,8 @@ static int __init hugepage_init(void)

      return 0;
  err_khugepaged:
-    unregister_shrinker(&deferred_split_shrinker);
-err_split_shrinker:
-    unregister_shrinker(&huge_zero_page_shrinker);
-err_hzp_shrinker:
+    thp_shrinker_exit();
+err_shrinker:
      khugepaged_destroy();
  err_slab:
      hugepage_exit_sysfs(hugepage_kobj);

@@ -2851,7 +2880,7 @@ void deferred_split_folio(struct folio *folio)

  #ifdef CONFIG_MEMCG
          if (memcg)
              set_shrinker_bit(memcg, folio_nid(folio),
-                     deferred_split_shrinker.id);
+                     deferred_split_shrinker->id);
  #endif
      }
      spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags);

@@ -2925,14 +2954,6 @@ static unsigned long deferred_split_scan(struct 

shrinker *shrink,
      return split;
  }
-static struct shrinker deferred_split_shrinker = {
-    .count_objects = deferred_split_count,
-    .scan_objects = deferred_split_scan,
-    .seeks = DEFAULT_SEEKS,
-    .flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE |
-         SHRINKER_NONSLAB,
-};
-
  #ifdef CONFIG_DEBUG_FS
  static void split_huge_pages_all(void)
  {