mm: vmscan: move shrinker-related code into a separate file

The mm/vmscan.c file is too large, so separate the shrinker-related code
from it into a separate file.  No functional changes.

Link: https://lkml.kernel.org/r/20230911092517.64141-3-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian König <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Vlastimil Babka <vbabka@suse.cz>
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: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.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: 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: 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: 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: 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: 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: Sean Paul <sean@poorly.run>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
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: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 0 insertions, 701 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 4062bcca5311..4a6551510b65 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -35,7 +35,6 @@
 #include <linux/cpuset.h>
 #include <linux/compaction.h>
 #include <linux/notifier.h>
-#include <linux/rwsem.h>
 #include <linux/delay.h>
 #include <linux/kthread.h>
 #include <linux/freezer.h>
@@ -188,246 +187,7 @@ struct scan_control {
  */
 int vm_swappiness = 60;
 
-LIST_HEAD(shrinker_list);
-DECLARE_RWSEM(shrinker_rwsem);
-
 #ifdef CONFIG_MEMCG
-static int shrinker_nr_max;
-
-/* The shrinker_info is expanded in a batch of BITS_PER_LONG */
-static inline int shrinker_map_size(int nr_items)
-{
-	return (DIV_ROUND_UP(nr_items, BITS_PER_LONG) * sizeof(unsigned long));
-}
-
-static inline int shrinker_defer_size(int nr_items)
-{
-	return (round_up(nr_items, BITS_PER_LONG) * sizeof(atomic_long_t));
-}
-
-static struct shrinker_info *shrinker_info_protected(struct mem_cgroup *memcg,
-						     int nid)
-{
-	return rcu_dereference_protected(memcg->nodeinfo[nid]->shrinker_info,
-					 lockdep_is_held(&shrinker_rwsem));
-}
-
-static int expand_one_shrinker_info(struct mem_cgroup *memcg,
-				    int map_size, int defer_size,
-				    int old_map_size, int old_defer_size,
-				    int new_nr_max)
-{
-	struct shrinker_info *new, *old;
-	struct mem_cgroup_per_node *pn;
-	int nid;
-	int size = map_size + defer_size;
-
-	for_each_node(nid) {
-		pn = memcg->nodeinfo[nid];
-		old = shrinker_info_protected(memcg, nid);
-		/* Not yet online memcg */
-		if (!old)
-			return 0;
-
-		/* Already expanded this shrinker_info */
-		if (new_nr_max <= old->map_nr_max)
-			continue;
-
-		new = kvmalloc_node(sizeof(*new) + size, GFP_KERNEL, nid);
-		if (!new)
-			return -ENOMEM;
-
-		new->nr_deferred = (atomic_long_t *)(new + 1);
-		new->map = (void *)new->nr_deferred + defer_size;
-		new->map_nr_max = new_nr_max;
-
-		/* map: set all old bits, clear all new bits */
-		memset(new->map, (int)0xff, old_map_size);
-		memset((void *)new->map + old_map_size, 0, map_size - old_map_size);
-		/* nr_deferred: copy old values, clear all new values */
-		memcpy(new->nr_deferred, old->nr_deferred, old_defer_size);
-		memset((void *)new->nr_deferred + old_defer_size, 0,
-		       defer_size - old_defer_size);
-
-		rcu_assign_pointer(pn->shrinker_info, new);
-		kvfree_rcu(old, rcu);
-	}
-
-	return 0;
-}
-
-void free_shrinker_info(struct mem_cgroup *memcg)
-{
-	struct mem_cgroup_per_node *pn;
-	struct shrinker_info *info;
-	int nid;
-
-	for_each_node(nid) {
-		pn = memcg->nodeinfo[nid];
-		info = rcu_dereference_protected(pn->shrinker_info, true);
-		kvfree(info);
-		rcu_assign_pointer(pn->shrinker_info, NULL);
-	}
-}
-
-int alloc_shrinker_info(struct mem_cgroup *memcg)
-{
-	struct shrinker_info *info;
-	int nid, size, ret = 0;
-	int map_size, defer_size = 0;
-
-	down_write(&shrinker_rwsem);
-	map_size = shrinker_map_size(shrinker_nr_max);
-	defer_size = shrinker_defer_size(shrinker_nr_max);
-	size = map_size + defer_size;
-	for_each_node(nid) {
-		info = kvzalloc_node(sizeof(*info) + size, GFP_KERNEL, nid);
-		if (!info) {
-			free_shrinker_info(memcg);
-			ret = -ENOMEM;
-			break;
-		}
-		info->nr_deferred = (atomic_long_t *)(info + 1);
-		info->map = (void *)info->nr_deferred + defer_size;
-		info->map_nr_max = shrinker_nr_max;
-		rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_info, info);
-	}
-	up_write(&shrinker_rwsem);
-
-	return ret;
-}
-
-static int expand_shrinker_info(int new_id)
-{
-	int ret = 0;
-	int new_nr_max = round_up(new_id + 1, BITS_PER_LONG);
-	int map_size, defer_size = 0;
-	int old_map_size, old_defer_size = 0;
-	struct mem_cgroup *memcg;
-
-	if (!root_mem_cgroup)
-		goto out;
-
-	lockdep_assert_held(&shrinker_rwsem);
-
-	map_size = shrinker_map_size(new_nr_max);
-	defer_size = shrinker_defer_size(new_nr_max);
-	old_map_size = shrinker_map_size(shrinker_nr_max);
-	old_defer_size = shrinker_defer_size(shrinker_nr_max);
-
-	memcg = mem_cgroup_iter(NULL, NULL, NULL);
-	do {
-		ret = expand_one_shrinker_info(memcg, map_size, defer_size,
-					       old_map_size, old_defer_size,
-					       new_nr_max);
-		if (ret) {
-			mem_cgroup_iter_break(NULL, memcg);
-			goto out;
-		}
-	} while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL);
-out:
-	if (!ret)
-		shrinker_nr_max = new_nr_max;
-
-	return ret;
-}
-
-void set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id)
-{
-	if (shrinker_id >= 0 && memcg && !mem_cgroup_is_root(memcg)) {
-		struct shrinker_info *info;
-
-		rcu_read_lock();
-		info = rcu_dereference(memcg->nodeinfo[nid]->shrinker_info);
-		if (!WARN_ON_ONCE(shrinker_id >= info->map_nr_max)) {
-			/* Pairs with smp mb in shrink_slab() */
-			smp_mb__before_atomic();
-			set_bit(shrinker_id, info->map);
-		}
-		rcu_read_unlock();
-	}
-}
-
-static DEFINE_IDR(shrinker_idr);
-
-static int prealloc_memcg_shrinker(struct shrinker *shrinker)
-{
-	int id, ret = -ENOMEM;
-
-	if (mem_cgroup_disabled())
-		return -ENOSYS;
-
-	down_write(&shrinker_rwsem);
-	/* This may call shrinker, so it must use down_read_trylock() */
-	id = idr_alloc(&shrinker_idr, shrinker, 0, 0, GFP_KERNEL);
-	if (id < 0)
-		goto unlock;
-
-	if (id >= shrinker_nr_max) {
-		if (expand_shrinker_info(id)) {
-			idr_remove(&shrinker_idr, id);
-			goto unlock;
-		}
-	}
-	shrinker->id = id;
-	ret = 0;
-unlock:
-	up_write(&shrinker_rwsem);
-	return ret;
-}
-
-static void unregister_memcg_shrinker(struct shrinker *shrinker)
-{
-	int id = shrinker->id;
-
-	BUG_ON(id < 0);
-
-	lockdep_assert_held(&shrinker_rwsem);
-
-	idr_remove(&shrinker_idr, id);
-}
-
-static long xchg_nr_deferred_memcg(int nid, struct shrinker *shrinker,
-				   struct mem_cgroup *memcg)
-{
-	struct shrinker_info *info;
-
-	info = shrinker_info_protected(memcg, nid);
-	return atomic_long_xchg(&info->nr_deferred[shrinker->id], 0);
-}
-
-static long add_nr_deferred_memcg(long nr, int nid, struct shrinker *shrinker,
-				  struct mem_cgroup *memcg)
-{
-	struct shrinker_info *info;
-
-	info = shrinker_info_protected(memcg, nid);
-	return atomic_long_add_return(nr, &info->nr_deferred[shrinker->id]);
-}
-
-void reparent_shrinker_deferred(struct mem_cgroup *memcg)
-{
-	int i, nid;
-	long nr;
-	struct mem_cgroup *parent;
-	struct shrinker_info *child_info, *parent_info;
-
-	parent = parent_mem_cgroup(memcg);
-	if (!parent)
-		parent = root_mem_cgroup;
-
-	/* Prevent from concurrent shrinker_info expand */
-	down_read(&shrinker_rwsem);
-	for_each_node(nid) {
-		child_info = shrinker_info_protected(memcg, nid);
-		parent_info = shrinker_info_protected(parent, nid);
-		for (i = 0; i < child_info->map_nr_max; i++) {
-			nr = atomic_long_read(&child_info->nr_deferred[i]);
-			atomic_long_add(nr, &parent_info->nr_deferred[i]);
-		}
-	}
-	up_read(&shrinker_rwsem);
-}
 
 /* Returns true for reclaim through cgroup limits or cgroup interfaces. */
 static bool cgroup_reclaim(struct scan_control *sc)
@@ -468,27 +228,6 @@ static bool writeback_throttling_sane(struct scan_control *sc)
 	return false;
 }
 #else
-static int prealloc_memcg_shrinker(struct shrinker *shrinker)
-{
-	return -ENOSYS;
-}
-
-static void unregister_memcg_shrinker(struct shrinker *shrinker)
-{
-}
-
-static long xchg_nr_deferred_memcg(int nid, struct shrinker *shrinker,
-				   struct mem_cgroup *memcg)
-{
-	return 0;
-}
-
-static long add_nr_deferred_memcg(long nr, int nid, struct shrinker *shrinker,
-				  struct mem_cgroup *memcg)
-{
-	return 0;
-}
-
 static bool cgroup_reclaim(struct scan_control *sc)
 {
 	return false;
@@ -557,39 +296,6 @@ static void flush_reclaim_state(struct scan_control *sc)
 	}
 }
 
-static long xchg_nr_deferred(struct shrinker *shrinker,
-			     struct shrink_control *sc)
-{
-	int nid = sc->nid;
-
-	if (!(shrinker->flags & SHRINKER_NUMA_AWARE))
-		nid = 0;
-
-	if (sc->memcg &&
-	    (shrinker->flags & SHRINKER_MEMCG_AWARE))
-		return xchg_nr_deferred_memcg(nid, shrinker,
-					      sc->memcg);
-
-	return atomic_long_xchg(&shrinker->nr_deferred[nid], 0);
-}
-
-
-static long add_nr_deferred(long nr, struct shrinker *shrinker,
-			    struct shrink_control *sc)
-{
-	int nid = sc->nid;
-
-	if (!(shrinker->flags & SHRINKER_NUMA_AWARE))
-		nid = 0;
-
-	if (sc->memcg &&
-	    (shrinker->flags & SHRINKER_MEMCG_AWARE))
-		return add_nr_deferred_memcg(nr, nid, shrinker,
-					     sc->memcg);
-
-	return atomic_long_add_return(nr, &shrinker->nr_deferred[nid]);
-}
-
 static bool can_demote(int nid, struct scan_control *sc)
 {
 	if (!numa_demotion_enabled)
@@ -671,413 +377,6 @@ static unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru,
 	return size;
 }
 
-/*
- * Add a shrinker callback to be called from the vm.
- */
-static int __prealloc_shrinker(struct shrinker *shrinker)
-{
-	unsigned int size;
-	int err;
-
-	if (shrinker->flags & SHRINKER_MEMCG_AWARE) {
-		err = prealloc_memcg_shrinker(shrinker);
-		if (err != -ENOSYS)
-			return err;
-
-		shrinker->flags &= ~SHRINKER_MEMCG_AWARE;
-	}
-
-	size = sizeof(*shrinker->nr_deferred);
-	if (shrinker->flags & SHRINKER_NUMA_AWARE)
-		size *= nr_node_ids;
-
-	shrinker->nr_deferred = kzalloc(size, GFP_KERNEL);
-	if (!shrinker->nr_deferred)
-		return -ENOMEM;
-
-	return 0;
-}
-
-#ifdef CONFIG_SHRINKER_DEBUG
-int prealloc_shrinker(struct shrinker *shrinker, const char *fmt, ...)
-{
-	va_list ap;
-	int err;
-
-	va_start(ap, fmt);
-	shrinker->name = kvasprintf_const(GFP_KERNEL, fmt, ap);
-	va_end(ap);
-	if (!shrinker->name)
-		return -ENOMEM;
-
-	err = __prealloc_shrinker(shrinker);
-	if (err) {
-		kfree_const(shrinker->name);
-		shrinker->name = NULL;
-	}
-
-	return err;
-}
-#else
-int prealloc_shrinker(struct shrinker *shrinker, const char *fmt, ...)
-{
-	return __prealloc_shrinker(shrinker);
-}
-#endif
-
-void free_prealloced_shrinker(struct shrinker *shrinker)
-{
-#ifdef CONFIG_SHRINKER_DEBUG
-	kfree_const(shrinker->name);
-	shrinker->name = NULL;
-#endif
-	if (shrinker->flags & SHRINKER_MEMCG_AWARE) {
-		down_write(&shrinker_rwsem);
-		unregister_memcg_shrinker(shrinker);
-		up_write(&shrinker_rwsem);
-		return;
-	}
-
-	kfree(shrinker->nr_deferred);
-	shrinker->nr_deferred = NULL;
-}
-
-void register_shrinker_prepared(struct shrinker *shrinker)
-{
-	down_write(&shrinker_rwsem);
-	list_add_tail(&shrinker->list, &shrinker_list);
-	shrinker->flags |= SHRINKER_REGISTERED;
-	shrinker_debugfs_add(shrinker);
-	up_write(&shrinker_rwsem);
-}
-
-static int __register_shrinker(struct shrinker *shrinker)
-{
-	int err = __prealloc_shrinker(shrinker);
-
-	if (err)
-		return err;
-	register_shrinker_prepared(shrinker);
-	return 0;
-}
-
-#ifdef CONFIG_SHRINKER_DEBUG
-int register_shrinker(struct shrinker *shrinker, const char *fmt, ...)
-{
-	va_list ap;
-	int err;
-
-	va_start(ap, fmt);
-	shrinker->name = kvasprintf_const(GFP_KERNEL, fmt, ap);
-	va_end(ap);
-	if (!shrinker->name)
-		return -ENOMEM;
-
-	err = __register_shrinker(shrinker);
-	if (err) {
-		kfree_const(shrinker->name);
-		shrinker->name = NULL;
-	}
-	return err;
-}
-#else
-int register_shrinker(struct shrinker *shrinker, const char *fmt, ...)
-{
-	return __register_shrinker(shrinker);
-}
-#endif
-EXPORT_SYMBOL(register_shrinker);
-
-/*
- * Remove one
- */
-void unregister_shrinker(struct shrinker *shrinker)
-{
-	struct dentry *debugfs_entry;
-	int debugfs_id;
-
-	if (!(shrinker->flags & SHRINKER_REGISTERED))
-		return;
-
-	down_write(&shrinker_rwsem);
-	list_del(&shrinker->list);
-	shrinker->flags &= ~SHRINKER_REGISTERED;
-	if (shrinker->flags & SHRINKER_MEMCG_AWARE)
-		unregister_memcg_shrinker(shrinker);
-	debugfs_entry = shrinker_debugfs_detach(shrinker, &debugfs_id);
-	up_write(&shrinker_rwsem);
-
-	shrinker_debugfs_remove(debugfs_entry, debugfs_id);
-
-	kfree(shrinker->nr_deferred);
-	shrinker->nr_deferred = NULL;
-}
-EXPORT_SYMBOL(unregister_shrinker);
-
-/**
- * synchronize_shrinkers - Wait for all running shrinkers to complete.
- *
- * This is equivalent to calling unregister_shrink() and register_shrinker(),
- * but atomically and with less overhead. This is useful to guarantee that all
- * shrinker invocations have seen an update, before freeing memory, similar to
- * rcu.
- */
-void synchronize_shrinkers(void)
-{
-	down_write(&shrinker_rwsem);
-	up_write(&shrinker_rwsem);
-}
-EXPORT_SYMBOL(synchronize_shrinkers);
-
-#define SHRINK_BATCH 128
-
-static unsigned long do_shrink_slab(struct shrink_control *shrinkctl,
-				    struct shrinker *shrinker, int priority)
-{
-	unsigned long freed = 0;
-	unsigned long long delta;
-	long total_scan;
-	long freeable;
-	long nr;
-	long new_nr;
-	long batch_size = shrinker->batch ? shrinker->batch
-					  : SHRINK_BATCH;
-	long scanned = 0, next_deferred;
-
-	freeable = shrinker->count_objects(shrinker, shrinkctl);
-	if (freeable == 0 || freeable == SHRINK_EMPTY)
-		return freeable;
-
-	/*
-	 * copy the current shrinker scan count into a local variable
-	 * and zero it so that other concurrent shrinker invocations
-	 * don't also do this scanning work.
-	 */
-	nr = xchg_nr_deferred(shrinker, shrinkctl);
-
-	if (shrinker->seeks) {
-		delta = freeable >> priority;
-		delta *= 4;
-		do_div(delta, shrinker->seeks);
-	} else {
-		/*
-		 * These objects don't require any IO to create. Trim
-		 * them aggressively under memory pressure to keep
-		 * them from causing refetches in the IO caches.
-		 */
-		delta = freeable / 2;
-	}
-
-	total_scan = nr >> priority;
-	total_scan += delta;
-	total_scan = min(total_scan, (2 * freeable));
-
-	trace_mm_shrink_slab_start(shrinker, shrinkctl, nr,
-				   freeable, delta, total_scan, priority);
-
-	/*
-	 * Normally, we should not scan less than batch_size objects in one
-	 * pass to avoid too frequent shrinker calls, but if the slab has less
-	 * than batch_size objects in total and we are really tight on memory,
-	 * we will try to reclaim all available objects, otherwise we can end
-	 * up failing allocations although there are plenty of reclaimable
-	 * objects spread over several slabs with usage less than the
-	 * batch_size.
-	 *
-	 * We detect the "tight on memory" situations by looking at the total
-	 * number of objects we want to scan (total_scan). If it is greater
-	 * than the total number of objects on slab (freeable), we must be
-	 * scanning at high prio and therefore should try to reclaim as much as
-	 * possible.
-	 */
-	while (total_scan >= batch_size ||
-	       total_scan >= freeable) {
-		unsigned long ret;
-		unsigned long nr_to_scan = min(batch_size, total_scan);
-
-		shrinkctl->nr_to_scan = nr_to_scan;
-		shrinkctl->nr_scanned = nr_to_scan;
-		ret = shrinker->scan_objects(shrinker, shrinkctl);
-		if (ret == SHRINK_STOP)
-			break;
-		freed += ret;
-
-		count_vm_events(SLABS_SCANNED, shrinkctl->nr_scanned);
-		total_scan -= shrinkctl->nr_scanned;
-		scanned += shrinkctl->nr_scanned;
-
-		cond_resched();
-	}
-
-	/*
-	 * The deferred work is increased by any new work (delta) that wasn't
-	 * done, decreased by old deferred work that was done now.
-	 *
-	 * And it is capped to two times of the freeable items.
-	 */
-	next_deferred = max_t(long, (nr + delta - scanned), 0);
-	next_deferred = min(next_deferred, (2 * freeable));
-
-	/*
-	 * move the unused scan count back into the shrinker in a
-	 * manner that handles concurrent updates.
-	 */
-	new_nr = add_nr_deferred(next_deferred, shrinker, shrinkctl);
-
-	trace_mm_shrink_slab_end(shrinker, shrinkctl->nid, freed, nr, new_nr, total_scan);
-	return freed;
-}
-
-#ifdef CONFIG_MEMCG
-static unsigned long shrink_slab_memcg(gfp_t gfp_mask, int nid,
-			struct mem_cgroup *memcg, int priority)
-{
-	struct shrinker_info *info;
-	unsigned long ret, freed = 0;
-	int i;
-
-	if (!mem_cgroup_online(memcg))
-		return 0;
-
-	if (!down_read_trylock(&shrinker_rwsem))
-		return 0;
-
-	info = shrinker_info_protected(memcg, nid);
-	if (unlikely(!info))
-		goto unlock;
-
-	for_each_set_bit(i, info->map, info->map_nr_max) {
-		struct shrink_control sc = {
-			.gfp_mask = gfp_mask,
-			.nid = nid,
-			.memcg = memcg,
-		};
-		struct shrinker *shrinker;
-
-		shrinker = idr_find(&shrinker_idr, i);
-		if (unlikely(!shrinker || !(shrinker->flags & SHRINKER_REGISTERED))) {
-			if (!shrinker)
-				clear_bit(i, info->map);
-			continue;
-		}
-
-		/* Call non-slab shrinkers even though kmem is disabled */
-		if (!memcg_kmem_online() &&
-		    !(shrinker->flags & SHRINKER_NONSLAB))
-			continue;
-
-		ret = do_shrink_slab(&sc, shrinker, priority);
-		if (ret == SHRINK_EMPTY) {
-			clear_bit(i, info->map);
-			/*
-			 * After the shrinker reported that it had no objects to
-			 * free, but before we cleared the corresponding bit in
-			 * the memcg shrinker map, a new object might have been
-			 * added. To make sure, we have the bit set in this
-			 * case, we invoke the shrinker one more time and reset
-			 * the bit if it reports that it is not empty anymore.
-			 * The memory barrier here pairs with the barrier in
-			 * set_shrinker_bit():
-			 *
-			 * list_lru_add()     shrink_slab_memcg()
-			 *   list_add_tail()    clear_bit()
-			 *   <MB>               <MB>
-			 *   set_bit()          do_shrink_slab()
-			 */
-			smp_mb__after_atomic();
-			ret = do_shrink_slab(&sc, shrinker, priority);
-			if (ret == SHRINK_EMPTY)
-				ret = 0;
-			else
-				set_shrinker_bit(memcg, nid, i);
-		}
-		freed += ret;
-
-		if (rwsem_is_contended(&shrinker_rwsem)) {
-			freed = freed ? : 1;
-			break;
-		}
-	}
-unlock:
-	up_read(&shrinker_rwsem);
-	return freed;
-}
-#else /* CONFIG_MEMCG */
-static unsigned long shrink_slab_memcg(gfp_t gfp_mask, int nid,
-			struct mem_cgroup *memcg, int priority)
-{
-	return 0;
-}
-#endif /* CONFIG_MEMCG */
-
-/**
- * shrink_slab - shrink slab caches
- * @gfp_mask: allocation context
- * @nid: node whose slab caches to target
- * @memcg: memory cgroup whose slab caches to target
- * @priority: the reclaim priority
- *
- * Call the shrink functions to age shrinkable caches.
- *
- * @nid is passed along to shrinkers with SHRINKER_NUMA_AWARE set,
- * unaware shrinkers will receive a node id of 0 instead.
- *
- * @memcg specifies the memory cgroup to target. Unaware shrinkers
- * are called only if it is the root cgroup.
- *
- * @priority is sc->priority, we take the number of objects and >> by priority
- * in order to get the scan target.
- *
- * Returns the number of reclaimed slab objects.
- */
-static unsigned long shrink_slab(gfp_t gfp_mask, int nid,
-				 struct mem_cgroup *memcg,
-				 int priority)
-{
-	unsigned long ret, freed = 0;
-	struct shrinker *shrinker;
-
-	/*
-	 * The root memcg might be allocated even though memcg is disabled
-	 * via "cgroup_disable=memory" boot parameter.  This could make
-	 * mem_cgroup_is_root() return false, then just run memcg slab
-	 * shrink, but skip global shrink.  This may result in premature
-	 * oom.
-	 */
-	if (!mem_cgroup_disabled() && !mem_cgroup_is_root(memcg))
-		return shrink_slab_memcg(gfp_mask, nid, memcg, priority);
-
-	if (!down_read_trylock(&shrinker_rwsem))
-		goto out;
-
-	list_for_each_entry(shrinker, &shrinker_list, list) {
-		struct shrink_control sc = {
-			.gfp_mask = gfp_mask,
-			.nid = nid,
-			.memcg = memcg,
-		};
-
-		ret = do_shrink_slab(&sc, shrinker, priority);
-		if (ret == SHRINK_EMPTY)
-			ret = 0;
-		freed += ret;
-		/*
-		 * Bail out if someone want to register a new shrinker to
-		 * prevent the registration from being stalled for long periods
-		 * by parallel ongoing shrinking.
-		 */
-		if (rwsem_is_contended(&shrinker_rwsem)) {
-			freed = freed ? : 1;
-			break;
-		}
-	}
-
-	up_read(&shrinker_rwsem);
-out:
-	cond_resched();
-	return freed;
-}
-
 static unsigned long drop_slab_node(int nid)
 {
 	unsigned long freed = 0;