mm: thp: dynamically allocate the thp-related shrinkers

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

Link: https://lkml.kernel.org/r/20230911094444.68966-18-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sean Paul <sean@poorly.run>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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 = {
+static struct shrinker *huge_zero_page_shrinker;
-	.count_objects = shrink_huge_zero_page_count,
-	.scan_objects = shrink_huge_zero_page_scan,
-	.seeks = DEFAULT_SEEKS,
-};
 
 #ifdef CONFIG_SYSFS
 static ssize_t enabled_show(struct kobject *kobj,
@@ -454,6 +454,38 @@ 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;
+	shrinker_register(huge_zero_page_shrinker);
+
+	deferred_split_shrinker->count_objects = deferred_split_count;
+	deferred_split_shrinker->scan_objects = deferred_split_scan;
+	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 +514,9 @@ static int __init hugepage_init(void)
 	if (err)
 		goto err_slab;
 
-	err = register_shrinker(&huge_zero_page_shrinker, "thp-zero");
+	err = thp_shrinker_init();
 	if (err)
-		goto err_hzp_shrinker;
+		goto err_shrinker;
-	err = register_shrinker(&deferred_split_shrinker, "thp-deferred_split");
-	if (err)
-		goto err_split_shrinker;
 
 	/*
 	 * By default disable transparent hugepages on smaller systems,
@@ -505,10 +534,8 @@ static int __init hugepage_init(void)
 
 	return 0;
 err_khugepaged:
-	unregister_shrinker(&deferred_split_shrinker);
+	thp_shrinker_exit();
-err_split_shrinker:
+err_shrinker:
-	unregister_shrinker(&huge_zero_page_shrinker);
-err_hzp_shrinker:
 	khugepaged_destroy();
 err_slab:
 	hugepage_exit_sysfs(hugepage_kobj);
@@ -2828,7 +2855,7 @@ 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);
@@ -2902,14 +2929,6 @@ next:
 	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)
 {