[PATCH v4 20/48] mm: thp: dynamically allocate the thp-related shrinkers

Qi Zheng
2023-08-07T11:32:06Z

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

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
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 947001a7cd42..5d0c7a0b651c 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;

#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 __init thp_shrinker_init(void)
+{
+ 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(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 __init thp_shrinker_exit(void)
+{
+ shrinker_free(huge_zero_page_shrinker);
+ shrinker_free(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);
@@ -2834,7 +2863,7 @@ 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);
@@ -2908,14 +2937,6 @@ 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)
{
--
2.30.2