[PATCH v3 -next 0/3] mm/hugetlb_cgroup: rework on cftypes

[PATCH v3 -next 0/3] mm/hugetlb_cgroup: rework on cftypes

[Xiu Jianfeng]

Hi,

This patchset provides an intuitive view of the control files through
static templates of cftypes, improve the readability of the code.

Changes from v2:
 - Add Reviewed-by tag of Oscar (the 1st patch)
 - Rebuild cft->private unconditionally

Changes from v1:
 - Fix smatch warnings of 'tmpl->name'

Xiu Jianfeng (3):
  mm/hugetlb_cgroup: identify the legacy using cgroup_subsys_on_dfl()
  mm/hugetlb_cgroup: prepare cftypes based on template
  mm/hugetlb_cgroup: switch to the new cftypes

 include/linux/hugetlb.h |   5 -
 mm/hugetlb_cgroup.c     | 302 ++++++++++++++++++++++------------------
 2 files changed, 164 insertions(+), 143 deletions(-)

-- 
2.34.1

[PATCH v3 -next 1/3] mm/hugetlb_cgroup: identify the legacy using cgroup_subsys_on_dfl()

[Xiu Jianfeng]

Currently the numa_stat file encodes 1 into .private using the micro
MEMFILE_PRIVATE() to identify the legacy. Actually, we can use
cgroup_subsys_on_dfl() instead. This is helpful to handle .private
in the static templates in the next patch.

Reviewed-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
---
 mm/hugetlb_cgroup.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
index e20339a346b9..45f94a869776 100644
--- a/mm/hugetlb_cgroup.c
+++ b/mm/hugetlb_cgroup.c
@@ -460,7 +460,7 @@ static int hugetlb_cgroup_read_numa_stat(struct seq_file *seq, void *dummy)
 	int nid;
 	struct cftype *cft = seq_cft(seq);
 	int idx = MEMFILE_IDX(cft->private);
-	bool legacy = MEMFILE_ATTR(cft->private);
+	bool legacy = !cgroup_subsys_on_dfl(hugetlb_cgrp_subsys);
 	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(seq_css(seq));
 	struct cgroup_subsys_state *css;
 	unsigned long usage;
@@ -839,7 +839,7 @@ static void __init __hugetlb_cgroup_file_legacy_init(int idx)
 	/* Add the numa stat file */
 	cft = &h->cgroup_files_legacy[8];
 	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.numa_stat", buf);
-	cft->private = MEMFILE_PRIVATE(idx, 1);
+	cft->private = MEMFILE_PRIVATE(idx, 0);
 	cft->seq_show = hugetlb_cgroup_read_numa_stat;
 
 	/* NULL terminate the last cft */
-- 
2.34.1

[PATCH v3 -next 2/3] mm/hugetlb_cgroup: prepare cftypes based on template

[Xiu Jianfeng]

Unlike other cgroup subsystems, the hugetlb cgroup does not provide
a static array of cftype that explicitly displays the properties,
handling functions, etc., of each file. Instead, it dynamically creates
the attribute of cftypes based on the hstate during the startup
procedure. This reduces the readability of the code.

To fix this issue, introduce two templates of cftypes, and rebuild the
attributes according to the hstate to make it ready to be added to
cgroup framework.

Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
---
 mm/hugetlb_cgroup.c | 156 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 156 insertions(+)

diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
index 45f94a869776..43aae8f88d5f 100644
--- a/mm/hugetlb_cgroup.c
+++ b/mm/hugetlb_cgroup.c
@@ -27,7 +27,17 @@
 #define MEMFILE_IDX(val)	(((val) >> 16) & 0xffff)
 #define MEMFILE_ATTR(val)	((val) & 0xffff)
 
+/* Use t->m[0] to encode the offset */
+#define MEMFILE_OFFSET(t, m0)	(((offsetof(t, m0) << 16) | sizeof_field(t, m0)))
+#define MEMFILE_OFFSET0(val)	(((val) >> 16) & 0xffff)
+#define MEMFILE_FIELD_SIZE(val)	((val) & 0xffff)
+
+#define DFL_TMPL_SIZE		ARRAY_SIZE(hugetlb_dfl_tmpl)
+#define LEGACY_TMPL_SIZE	ARRAY_SIZE(hugetlb_legacy_tmpl)
+
 static struct hugetlb_cgroup *root_h_cgroup __read_mostly;
+static struct cftype *dfl_files;
+static struct cftype *legacy_files;
 
 static inline struct page_counter *
 __hugetlb_cgroup_counter_from_cgroup(struct hugetlb_cgroup *h_cg, int idx,
@@ -702,12 +712,142 @@ static int hugetlb_events_local_show(struct seq_file *seq, void *v)
 	return __hugetlb_events_show(seq, true);
 }
 
+static struct cftype hugetlb_dfl_tmpl[] = {
+	{
+		.name = "max",
+		.private = RES_LIMIT,
+		.seq_show = hugetlb_cgroup_read_u64_max,
+		.write = hugetlb_cgroup_write_dfl,
+		.flags = CFTYPE_NOT_ON_ROOT,
+	},
+	{
+		.name = "rsvd.max",
+		.private = RES_RSVD_LIMIT,
+		.seq_show = hugetlb_cgroup_read_u64_max,
+		.write = hugetlb_cgroup_write_dfl,
+		.flags = CFTYPE_NOT_ON_ROOT,
+	},
+	{
+		.name = "current",
+		.private = RES_USAGE,
+		.seq_show = hugetlb_cgroup_read_u64_max,
+		.flags = CFTYPE_NOT_ON_ROOT,
+	},
+	{
+		.name = "rsvd.current",
+		.private = RES_RSVD_USAGE,
+		.seq_show = hugetlb_cgroup_read_u64_max,
+		.flags = CFTYPE_NOT_ON_ROOT,
+	},
+	{
+		.name = "events",
+		.seq_show = hugetlb_events_show,
+		.file_offset = MEMFILE_OFFSET(struct hugetlb_cgroup, events_file[0]),
+		.flags = CFTYPE_NOT_ON_ROOT,
+	},
+	{
+		.name = "events.local",
+		.seq_show = hugetlb_events_local_show,
+		.file_offset = MEMFILE_OFFSET(struct hugetlb_cgroup, events_local_file[0]),
+		.flags = CFTYPE_NOT_ON_ROOT,
+	},
+	{
+		.name = "numa_stat",
+		.seq_show = hugetlb_cgroup_read_numa_stat,
+		.flags = CFTYPE_NOT_ON_ROOT,
+	},
+	/* don't need terminator here */
+};
+
+static struct cftype hugetlb_legacy_tmpl[] = {
+	{
+		.name = "limit_in_bytes",
+		.private = RES_LIMIT,
+		.read_u64 = hugetlb_cgroup_read_u64,
+		.write = hugetlb_cgroup_write_legacy,
+	},
+	{
+		.name = "rsvd.limit_in_bytes",
+		.private = RES_RSVD_LIMIT,
+		.read_u64 = hugetlb_cgroup_read_u64,
+		.write = hugetlb_cgroup_write_legacy,
+	},
+	{
+		.name = "usage_in_bytes",
+		.private = RES_USAGE,
+		.read_u64 = hugetlb_cgroup_read_u64,
+	},
+	{
+		.name = "rsvd.usage_in_bytes",
+		.private = RES_RSVD_USAGE,
+		.read_u64 = hugetlb_cgroup_read_u64,
+	},
+	{
+		.name = "max_usage_in_bytes",
+		.private = RES_MAX_USAGE,
+		.write = hugetlb_cgroup_reset,
+		.read_u64 = hugetlb_cgroup_read_u64,
+	},
+	{
+		.name = "rsvd.max_usage_in_bytes",
+		.private = RES_RSVD_MAX_USAGE,
+		.write = hugetlb_cgroup_reset,
+		.read_u64 = hugetlb_cgroup_read_u64,
+	},
+	{
+		.name = "failcnt",
+		.private = RES_FAILCNT,
+		.write = hugetlb_cgroup_reset,
+		.read_u64 = hugetlb_cgroup_read_u64,
+	},
+	{
+		.name = "rsvd.failcnt",
+		.private = RES_RSVD_FAILCNT,
+		.write = hugetlb_cgroup_reset,
+		.read_u64 = hugetlb_cgroup_read_u64,
+	},
+	{
+		.name = "numa_stat",
+		.seq_show = hugetlb_cgroup_read_numa_stat,
+	},
+	/* don't need terminator here */
+};
+
+static void __init
+hugetlb_cgroup_cfttypes_init(struct hstate *h, struct cftype *cft,
+			     struct cftype *tmpl, int tmpl_size)
+{
+	char buf[32];
+	int i, idx = hstate_index(h);
+
+	/* format the size */
+	mem_fmt(buf, sizeof(buf), huge_page_size(h));
+
+	for (i = 0; i < tmpl_size; cft++, tmpl++, i++) {
+		*cft = *tmpl;
+		/* rebuild the name */
+		snprintf(cft->name, MAX_CFTYPE_NAME, "%s.%s", buf, tmpl->name);
+		/* rebuild the private */
+		cft->private = MEMFILE_PRIVATE(idx, tmpl->private);
+		/* rebuild the file_offset */
+		if (tmpl->file_offset) {
+			unsigned int offset = tmpl->file_offset;
+
+			cft->file_offset = MEMFILE_OFFSET0(offset) +
+					   MEMFILE_FIELD_SIZE(offset) * idx;
+		}
+	}
+}
+
 static void __init __hugetlb_cgroup_file_dfl_init(int idx)
 {
 	char buf[32];
 	struct cftype *cft;
 	struct hstate *h = &hstates[idx];
 
+	hugetlb_cgroup_cfttypes_init(h, dfl_files + idx * DFL_TMPL_SIZE,
+				     hugetlb_dfl_tmpl, DFL_TMPL_SIZE);
+
 	/* format the size */
 	mem_fmt(buf, sizeof(buf), huge_page_size(h));
 
@@ -779,6 +919,9 @@ static void __init __hugetlb_cgroup_file_legacy_init(int idx)
 	struct cftype *cft;
 	struct hstate *h = &hstates[idx];
 
+	hugetlb_cgroup_cfttypes_init(h, legacy_files + idx * LEGACY_TMPL_SIZE,
+				     hugetlb_legacy_tmpl, LEGACY_TMPL_SIZE);
+
 	/* format the size */
 	mem_fmt(buf, sizeof(buf), huge_page_size(h));
 
@@ -856,10 +999,23 @@ static void __init __hugetlb_cgroup_file_init(int idx)
 	__hugetlb_cgroup_file_legacy_init(idx);
 }
 
+static void __init __hugetlb_cgroup_file_pre_init(void)
+{
+	int cft_count;
+
+	cft_count = hugetlb_max_hstate * DFL_TMPL_SIZE + 1; /* add terminator */
+	dfl_files = kcalloc(cft_count, sizeof(struct cftype), GFP_KERNEL);
+	BUG_ON(!dfl_files);
+	cft_count = hugetlb_max_hstate * LEGACY_TMPL_SIZE + 1; /* add terminator */
+	legacy_files = kcalloc(cft_count, sizeof(struct cftype), GFP_KERNEL);
+	BUG_ON(!legacy_files);
+}
+
 void __init hugetlb_cgroup_file_init(void)
 {
 	struct hstate *h;
 
+	__hugetlb_cgroup_file_pre_init();
 	for_each_hstate(h)
 		__hugetlb_cgroup_file_init(hstate_index(h));
 }
-- 
2.34.1

[PATCH v3 -next 3/3] mm/hugetlb_cgroup: switch to the new cftypes

[Xiu Jianfeng]

The previous patch has already reconstructed the cftype attributes
based on the templates and saved them in dfl_cftypes and legacy_cftypes.
then remove the old procedure and switch to the new cftypes.

Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
---
 include/linux/hugetlb.h |   5 --
 mm/hugetlb_cgroup.c     | 163 +++++-----------------------------------
 2 files changed, 17 insertions(+), 151 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 279aca379b95..a951c0d06061 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -686,11 +686,6 @@ struct hstate {
 	unsigned int nr_huge_pages_node[MAX_NUMNODES];
 	unsigned int free_huge_pages_node[MAX_NUMNODES];
 	unsigned int surplus_huge_pages_node[MAX_NUMNODES];
-#ifdef CONFIG_CGROUP_HUGETLB
-	/* cgroup control files */
-	struct cftype cgroup_files_dfl[8];
-	struct cftype cgroup_files_legacy[10];
-#endif
 	char name[HSTATE_NAME_LEN];
 };
 
diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
index 43aae8f88d5f..2b899c4ae968 100644
--- a/mm/hugetlb_cgroup.c
+++ b/mm/hugetlb_cgroup.c
@@ -839,164 +839,26 @@ hugetlb_cgroup_cfttypes_init(struct hstate *h, struct cftype *cft,
 	}
 }
 
-static void __init __hugetlb_cgroup_file_dfl_init(int idx)
+static void __init __hugetlb_cgroup_file_dfl_init(struct hstate *h)
 {
-	char buf[32];
-	struct cftype *cft;
-	struct hstate *h = &hstates[idx];
+	int idx = hstate_index(h);
 
 	hugetlb_cgroup_cfttypes_init(h, dfl_files + idx * DFL_TMPL_SIZE,
 				     hugetlb_dfl_tmpl, DFL_TMPL_SIZE);
-
-	/* format the size */
-	mem_fmt(buf, sizeof(buf), huge_page_size(h));
-
-	/* Add the limit file */
-	cft = &h->cgroup_files_dfl[0];
-	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max", buf);
-	cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT);
-	cft->seq_show = hugetlb_cgroup_read_u64_max;
-	cft->write = hugetlb_cgroup_write_dfl;
-	cft->flags = CFTYPE_NOT_ON_ROOT;
-
-	/* Add the reservation limit file */
-	cft = &h->cgroup_files_dfl[1];
-	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.max", buf);
-	cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_LIMIT);
-	cft->seq_show = hugetlb_cgroup_read_u64_max;
-	cft->write = hugetlb_cgroup_write_dfl;
-	cft->flags = CFTYPE_NOT_ON_ROOT;
-
-	/* Add the current usage file */
-	cft = &h->cgroup_files_dfl[2];
-	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.current", buf);
-	cft->private = MEMFILE_PRIVATE(idx, RES_USAGE);
-	cft->seq_show = hugetlb_cgroup_read_u64_max;
-	cft->flags = CFTYPE_NOT_ON_ROOT;
-
-	/* Add the current reservation usage file */
-	cft = &h->cgroup_files_dfl[3];
-	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.current", buf);
-	cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_USAGE);
-	cft->seq_show = hugetlb_cgroup_read_u64_max;
-	cft->flags = CFTYPE_NOT_ON_ROOT;
-
-	/* Add the events file */
-	cft = &h->cgroup_files_dfl[4];
-	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.events", buf);
-	cft->private = MEMFILE_PRIVATE(idx, 0);
-	cft->seq_show = hugetlb_events_show;
-	cft->file_offset = offsetof(struct hugetlb_cgroup, events_file[idx]);
-	cft->flags = CFTYPE_NOT_ON_ROOT;
-
-	/* Add the events.local file */
-	cft = &h->cgroup_files_dfl[5];
-	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.events.local", buf);
-	cft->private = MEMFILE_PRIVATE(idx, 0);
-	cft->seq_show = hugetlb_events_local_show;
-	cft->file_offset = offsetof(struct hugetlb_cgroup,
-				    events_local_file[idx]);
-	cft->flags = CFTYPE_NOT_ON_ROOT;
-
-	/* Add the numa stat file */
-	cft = &h->cgroup_files_dfl[6];
-	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.numa_stat", buf);
-	cft->private = MEMFILE_PRIVATE(idx, 0);
-	cft->seq_show = hugetlb_cgroup_read_numa_stat;
-	cft->flags = CFTYPE_NOT_ON_ROOT;
-
-	/* NULL terminate the last cft */
-	cft = &h->cgroup_files_dfl[7];
-	memset(cft, 0, sizeof(*cft));
-
-	WARN_ON(cgroup_add_dfl_cftypes(&hugetlb_cgrp_subsys,
-				       h->cgroup_files_dfl));
 }
 
-static void __init __hugetlb_cgroup_file_legacy_init(int idx)
+static void __init __hugetlb_cgroup_file_legacy_init(struct hstate *h)
 {
-	char buf[32];
-	struct cftype *cft;
-	struct hstate *h = &hstates[idx];
+	int idx = hstate_index(h);
 
 	hugetlb_cgroup_cfttypes_init(h, legacy_files + idx * LEGACY_TMPL_SIZE,
 				     hugetlb_legacy_tmpl, LEGACY_TMPL_SIZE);
-
-	/* format the size */
-	mem_fmt(buf, sizeof(buf), huge_page_size(h));
-
-	/* Add the limit file */
-	cft = &h->cgroup_files_legacy[0];
-	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.limit_in_bytes", buf);
-	cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT);
-	cft->read_u64 = hugetlb_cgroup_read_u64;
-	cft->write = hugetlb_cgroup_write_legacy;
-
-	/* Add the reservation limit file */
-	cft = &h->cgroup_files_legacy[1];
-	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.limit_in_bytes", buf);
-	cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_LIMIT);
-	cft->read_u64 = hugetlb_cgroup_read_u64;
-	cft->write = hugetlb_cgroup_write_legacy;
-
-	/* Add the usage file */
-	cft = &h->cgroup_files_legacy[2];
-	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.usage_in_bytes", buf);
-	cft->private = MEMFILE_PRIVATE(idx, RES_USAGE);
-	cft->read_u64 = hugetlb_cgroup_read_u64;
-
-	/* Add the reservation usage file */
-	cft = &h->cgroup_files_legacy[3];
-	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.usage_in_bytes", buf);
-	cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_USAGE);
-	cft->read_u64 = hugetlb_cgroup_read_u64;
-
-	/* Add the MAX usage file */
-	cft = &h->cgroup_files_legacy[4];
-	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max_usage_in_bytes", buf);
-	cft->private = MEMFILE_PRIVATE(idx, RES_MAX_USAGE);
-	cft->write = hugetlb_cgroup_reset;
-	cft->read_u64 = hugetlb_cgroup_read_u64;
-
-	/* Add the MAX reservation usage file */
-	cft = &h->cgroup_files_legacy[5];
-	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.max_usage_in_bytes", buf);
-	cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_MAX_USAGE);
-	cft->write = hugetlb_cgroup_reset;
-	cft->read_u64 = hugetlb_cgroup_read_u64;
-
-	/* Add the failcntfile */
-	cft = &h->cgroup_files_legacy[6];
-	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.failcnt", buf);
-	cft->private = MEMFILE_PRIVATE(idx, RES_FAILCNT);
-	cft->write = hugetlb_cgroup_reset;
-	cft->read_u64 = hugetlb_cgroup_read_u64;
-
-	/* Add the reservation failcntfile */
-	cft = &h->cgroup_files_legacy[7];
-	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.failcnt", buf);
-	cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_FAILCNT);
-	cft->write = hugetlb_cgroup_reset;
-	cft->read_u64 = hugetlb_cgroup_read_u64;
-
-	/* Add the numa stat file */
-	cft = &h->cgroup_files_legacy[8];
-	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.numa_stat", buf);
-	cft->private = MEMFILE_PRIVATE(idx, 0);
-	cft->seq_show = hugetlb_cgroup_read_numa_stat;
-
-	/* NULL terminate the last cft */
-	cft = &h->cgroup_files_legacy[9];
-	memset(cft, 0, sizeof(*cft));
-
-	WARN_ON(cgroup_add_legacy_cftypes(&hugetlb_cgrp_subsys,
-					  h->cgroup_files_legacy));
 }
 
-static void __init __hugetlb_cgroup_file_init(int idx)
+static void __init __hugetlb_cgroup_file_init(struct hstate *h)
 {
-	__hugetlb_cgroup_file_dfl_init(idx);
-	__hugetlb_cgroup_file_legacy_init(idx);
+	__hugetlb_cgroup_file_dfl_init(h);
+	__hugetlb_cgroup_file_legacy_init(h);
 }
 
 static void __init __hugetlb_cgroup_file_pre_init(void)
@@ -1011,13 +873,22 @@ static void __init __hugetlb_cgroup_file_pre_init(void)
 	BUG_ON(!legacy_files);
 }
 
+static void __init __hugetlb_cgroup_file_post_init(void)
+{
+	WARN_ON(cgroup_add_dfl_cftypes(&hugetlb_cgrp_subsys,
+				       dfl_files));
+	WARN_ON(cgroup_add_legacy_cftypes(&hugetlb_cgrp_subsys,
+					  legacy_files));
+}
+
 void __init hugetlb_cgroup_file_init(void)
 {
 	struct hstate *h;
 
 	__hugetlb_cgroup_file_pre_init();
 	for_each_hstate(h)
-		__hugetlb_cgroup_file_init(hstate_index(h));
+		__hugetlb_cgroup_file_init(h);
+	__hugetlb_cgroup_file_post_init();
 }
 
 /*
-- 
2.34.1

Re: [PATCH v3 -next 3/3] mm/hugetlb_cgroup: switch to the new cftypes

[Marek Szyprowski]

Dear All,

On 12.06.2024 11:24, Xiu Jianfeng wrote:
> The previous patch has already reconstructed the cftype attributes
> based on the templates and saved them in dfl_cftypes and legacy_cftypes.
> then remove the old procedure and switch to the new cftypes.
>
> Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>

This patch landed in yesterday's linux-next (next-20240617) as commit 
11308a02a56cc ("mm/hugetlb_cgroup: switch to the new cftypes"). In my 
daily tests I found that it triggers the following lock dependency 
checker warning on most of my ARM64 test machines:

BUG: key ffff000005c080d8 has not been registered!
------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(1)
WARNING: CPU: 1 PID: 1080 at kernel/locking/lockdep.c:4895 
lockdep_init_map_type+0x1cc/0x284
Modules linked in: ipv6
CPU: 1 PID: 1080 Comm: cgmanager Not tainted 6.10.0-rc3+ #1011
Hardware name: linux,dummy-virt (DT)
pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : lockdep_init_map_type+0x1cc/0x284
lr : lockdep_init_map_type+0x1cc/0x284
...
Call trace:
  lockdep_init_map_type+0x1cc/0x284
  __kernfs_create_file+0x7c/0x138
  cgroup_addrm_files+0x170/0x360
  css_populate_dir+0x70/0x174
  cgroup_apply_control_enable+0x128/0x378
  rebind_subsystems+0x384/0x504
  cgroup_setup_root+0x224/0x420
  cgroup1_get_tree+0x248/0x36c
  vfs_get_tree+0x28/0xe8
  path_mount+0x3e8/0xb78
  __arm64_sys_mount+0x1f0/0x2dc
  invoke_syscall+0x48/0x118
  el0_svc_common.constprop.0+0x40/0xe8
  do_el0_svc_compat+0x20/0x3c
  el0_svc_compat+0x44/0xe0
  el0t_32_sync_handler+0x98/0x148
  el0t_32_sync+0x194/0x198
irq event stamp: 8225
hardirqs last  enabled at (8225): [<ffff800080136134>] 
console_unlock+0x164/0x190
hardirqs last disabled at (8224): [<ffff800080136120>] 
console_unlock+0x150/0x190
softirqs last  enabled at (8214): [<ffff8000800ae1f4>] 
handle_softirqs+0x4dc/0x4f4
softirqs last disabled at (8207): [<ffff8000800105d4>] 
__do_softirq+0x14/0x20
---[ end trace 0000000000000000 ]---

It looks that something is not properly intialized. Reverting $subject 
on top of linux-next fixes this issue.

I've used defconfig with some debug options enabled and some drivers 
compiled-in (if this matters):

make ARCH=arm64 defconfig

./scripts/config -e BLK_DEV_RAM --set-val BLK_DEV_RAM_COUNT 4 --set-val 
BLK_DEV_RAM_SIZE 81920 --set-val CMA_SIZE_MBYTES 96 -e PROVE_LOCKING -e 
DEBUG_ATOMIC_SLEEP -e STAGING -e I2C_GPIO -e PM_DEBUG -e 
PM_ADVANCED_DEBUG -e USB_GADGET -e USB_ETH -e CONFIG_DEVFREQ_THERMAL -e 
CONFIG_BRCMFMAC_PCIE -e CONFIG_NFC -d ARCH_SUNXI -d ARCH_ALPINE -d 
DRM_NOUVEAU -d ARCH_BCM_IPROC -d ARCH_BERLIN -d ARCH_BRCMSTB -d 
ARCH_LAYERSCAPE -d ARCH_LG1K -d ARCH_HISI -d ARCH_MEDIATEK -d ARCH_MVEBU 
-d ARCH_SEATTLE -d ARCH_SYNQUACER -d ARCH_RENESAS -d ARCH_STRATIX10 -d 
ARCH_TEGRA -d ARCH_SPRD -d ARCH_THUNDER -d ARCH_THUNDER2 -d 
ARCH_UNIPHIER -d ARCH_XGENE -d ARCH_ZX -d ARCH_ZYNQMP -d HIBERNATION -d 
CLK_SUNXI -d CONFIG_EFI -d CONFIG_TEE -e FW_CFG_SYSFS


> ---
>   include/linux/hugetlb.h |   5 --
>   mm/hugetlb_cgroup.c     | 163 +++++-----------------------------------
>   2 files changed, 17 insertions(+), 151 deletions(-)
>
> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> index 279aca379b95..a951c0d06061 100644
> --- a/include/linux/hugetlb.h
> +++ b/include/linux/hugetlb.h
> @@ -686,11 +686,6 @@ struct hstate {
>   	unsigned int nr_huge_pages_node[MAX_NUMNODES];
>   	unsigned int free_huge_pages_node[MAX_NUMNODES];
>   	unsigned int surplus_huge_pages_node[MAX_NUMNODES];
> -#ifdef CONFIG_CGROUP_HUGETLB
> -	/* cgroup control files */
> -	struct cftype cgroup_files_dfl[8];
> -	struct cftype cgroup_files_legacy[10];
> -#endif
>   	char name[HSTATE_NAME_LEN];
>   };
>   
> diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
> index 43aae8f88d5f..2b899c4ae968 100644
> --- a/mm/hugetlb_cgroup.c
> +++ b/mm/hugetlb_cgroup.c
> @@ -839,164 +839,26 @@ hugetlb_cgroup_cfttypes_init(struct hstate *h, struct cftype *cft,
>   	}
>   }
>   
> -static void __init __hugetlb_cgroup_file_dfl_init(int idx)
> +static void __init __hugetlb_cgroup_file_dfl_init(struct hstate *h)
>   {
> -	char buf[32];
> -	struct cftype *cft;
> -	struct hstate *h = &hstates[idx];
> +	int idx = hstate_index(h);
>   
>   	hugetlb_cgroup_cfttypes_init(h, dfl_files + idx * DFL_TMPL_SIZE,
>   				     hugetlb_dfl_tmpl, DFL_TMPL_SIZE);
> -
> -	/* format the size */
> -	mem_fmt(buf, sizeof(buf), huge_page_size(h));
> -
> -	/* Add the limit file */
> -	cft = &h->cgroup_files_dfl[0];
> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max", buf);
> -	cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT);
> -	cft->seq_show = hugetlb_cgroup_read_u64_max;
> -	cft->write = hugetlb_cgroup_write_dfl;
> -	cft->flags = CFTYPE_NOT_ON_ROOT;
> -
> -	/* Add the reservation limit file */
> -	cft = &h->cgroup_files_dfl[1];
> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.max", buf);
> -	cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_LIMIT);
> -	cft->seq_show = hugetlb_cgroup_read_u64_max;
> -	cft->write = hugetlb_cgroup_write_dfl;
> -	cft->flags = CFTYPE_NOT_ON_ROOT;
> -
> -	/* Add the current usage file */
> -	cft = &h->cgroup_files_dfl[2];
> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.current", buf);
> -	cft->private = MEMFILE_PRIVATE(idx, RES_USAGE);
> -	cft->seq_show = hugetlb_cgroup_read_u64_max;
> -	cft->flags = CFTYPE_NOT_ON_ROOT;
> -
> -	/* Add the current reservation usage file */
> -	cft = &h->cgroup_files_dfl[3];
> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.current", buf);
> -	cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_USAGE);
> -	cft->seq_show = hugetlb_cgroup_read_u64_max;
> -	cft->flags = CFTYPE_NOT_ON_ROOT;
> -
> -	/* Add the events file */
> -	cft = &h->cgroup_files_dfl[4];
> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.events", buf);
> -	cft->private = MEMFILE_PRIVATE(idx, 0);
> -	cft->seq_show = hugetlb_events_show;
> -	cft->file_offset = offsetof(struct hugetlb_cgroup, events_file[idx]);
> -	cft->flags = CFTYPE_NOT_ON_ROOT;
> -
> -	/* Add the events.local file */
> -	cft = &h->cgroup_files_dfl[5];
> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.events.local", buf);
> -	cft->private = MEMFILE_PRIVATE(idx, 0);
> -	cft->seq_show = hugetlb_events_local_show;
> -	cft->file_offset = offsetof(struct hugetlb_cgroup,
> -				    events_local_file[idx]);
> -	cft->flags = CFTYPE_NOT_ON_ROOT;
> -
> -	/* Add the numa stat file */
> -	cft = &h->cgroup_files_dfl[6];
> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.numa_stat", buf);
> -	cft->private = MEMFILE_PRIVATE(idx, 0);
> -	cft->seq_show = hugetlb_cgroup_read_numa_stat;
> -	cft->flags = CFTYPE_NOT_ON_ROOT;
> -
> -	/* NULL terminate the last cft */
> -	cft = &h->cgroup_files_dfl[7];
> -	memset(cft, 0, sizeof(*cft));
> -
> -	WARN_ON(cgroup_add_dfl_cftypes(&hugetlb_cgrp_subsys,
> -				       h->cgroup_files_dfl));
>   }
>   
> -static void __init __hugetlb_cgroup_file_legacy_init(int idx)
> +static void __init __hugetlb_cgroup_file_legacy_init(struct hstate *h)
>   {
> -	char buf[32];
> -	struct cftype *cft;
> -	struct hstate *h = &hstates[idx];
> +	int idx = hstate_index(h);
>   
>   	hugetlb_cgroup_cfttypes_init(h, legacy_files + idx * LEGACY_TMPL_SIZE,
>   				     hugetlb_legacy_tmpl, LEGACY_TMPL_SIZE);
> -
> -	/* format the size */
> -	mem_fmt(buf, sizeof(buf), huge_page_size(h));
> -
> -	/* Add the limit file */
> -	cft = &h->cgroup_files_legacy[0];
> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.limit_in_bytes", buf);
> -	cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT);
> -	cft->read_u64 = hugetlb_cgroup_read_u64;
> -	cft->write = hugetlb_cgroup_write_legacy;
> -
> -	/* Add the reservation limit file */
> -	cft = &h->cgroup_files_legacy[1];
> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.limit_in_bytes", buf);
> -	cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_LIMIT);
> -	cft->read_u64 = hugetlb_cgroup_read_u64;
> -	cft->write = hugetlb_cgroup_write_legacy;
> -
> -	/* Add the usage file */
> -	cft = &h->cgroup_files_legacy[2];
> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.usage_in_bytes", buf);
> -	cft->private = MEMFILE_PRIVATE(idx, RES_USAGE);
> -	cft->read_u64 = hugetlb_cgroup_read_u64;
> -
> -	/* Add the reservation usage file */
> -	cft = &h->cgroup_files_legacy[3];
> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.usage_in_bytes", buf);
> -	cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_USAGE);
> -	cft->read_u64 = hugetlb_cgroup_read_u64;
> -
> -	/* Add the MAX usage file */
> -	cft = &h->cgroup_files_legacy[4];
> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max_usage_in_bytes", buf);
> -	cft->private = MEMFILE_PRIVATE(idx, RES_MAX_USAGE);
> -	cft->write = hugetlb_cgroup_reset;
> -	cft->read_u64 = hugetlb_cgroup_read_u64;
> -
> -	/* Add the MAX reservation usage file */
> -	cft = &h->cgroup_files_legacy[5];
> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.max_usage_in_bytes", buf);
> -	cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_MAX_USAGE);
> -	cft->write = hugetlb_cgroup_reset;
> -	cft->read_u64 = hugetlb_cgroup_read_u64;
> -
> -	/* Add the failcntfile */
> -	cft = &h->cgroup_files_legacy[6];
> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.failcnt", buf);
> -	cft->private = MEMFILE_PRIVATE(idx, RES_FAILCNT);
> -	cft->write = hugetlb_cgroup_reset;
> -	cft->read_u64 = hugetlb_cgroup_read_u64;
> -
> -	/* Add the reservation failcntfile */
> -	cft = &h->cgroup_files_legacy[7];
> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.failcnt", buf);
> -	cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_FAILCNT);
> -	cft->write = hugetlb_cgroup_reset;
> -	cft->read_u64 = hugetlb_cgroup_read_u64;
> -
> -	/* Add the numa stat file */
> -	cft = &h->cgroup_files_legacy[8];
> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.numa_stat", buf);
> -	cft->private = MEMFILE_PRIVATE(idx, 0);
> -	cft->seq_show = hugetlb_cgroup_read_numa_stat;
> -
> -	/* NULL terminate the last cft */
> -	cft = &h->cgroup_files_legacy[9];
> -	memset(cft, 0, sizeof(*cft));
> -
> -	WARN_ON(cgroup_add_legacy_cftypes(&hugetlb_cgrp_subsys,
> -					  h->cgroup_files_legacy));
>   }
>   
> -static void __init __hugetlb_cgroup_file_init(int idx)
> +static void __init __hugetlb_cgroup_file_init(struct hstate *h)
>   {
> -	__hugetlb_cgroup_file_dfl_init(idx);
> -	__hugetlb_cgroup_file_legacy_init(idx);
> +	__hugetlb_cgroup_file_dfl_init(h);
> +	__hugetlb_cgroup_file_legacy_init(h);
>   }
>   
>   static void __init __hugetlb_cgroup_file_pre_init(void)
> @@ -1011,13 +873,22 @@ static void __init __hugetlb_cgroup_file_pre_init(void)
>   	BUG_ON(!legacy_files);
>   }
>   
> +static void __init __hugetlb_cgroup_file_post_init(void)
> +{
> +	WARN_ON(cgroup_add_dfl_cftypes(&hugetlb_cgrp_subsys,
> +				       dfl_files));
> +	WARN_ON(cgroup_add_legacy_cftypes(&hugetlb_cgrp_subsys,
> +					  legacy_files));
> +}
> +
>   void __init hugetlb_cgroup_file_init(void)
>   {
>   	struct hstate *h;
>   
>   	__hugetlb_cgroup_file_pre_init();
>   	for_each_hstate(h)
> -		__hugetlb_cgroup_file_init(hstate_index(h));
> +		__hugetlb_cgroup_file_init(h);
> +	__hugetlb_cgroup_file_post_init();
>   }
>   
>   /*

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Re: [PATCH v3 -next 3/3] mm/hugetlb_cgroup: switch to the new cftypes

[xiujianfeng]

Hi,

On 2024/6/18 20:55, Marek Szyprowski wrote:
> Dear All,
> 
> On 12.06.2024 11:24, Xiu Jianfeng wrote:
>> The previous patch has already reconstructed the cftype attributes
>> based on the templates and saved them in dfl_cftypes and legacy_cftypes.
>> then remove the old procedure and switch to the new cftypes.
>>
>> Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
> 
> This patch landed in yesterday's linux-next (next-20240617) as commit 
> 11308a02a56cc ("mm/hugetlb_cgroup: switch to the new cftypes"). In my 
> daily tests I found that it triggers the following lock dependency 
> checker warning on most of my ARM64 test machines:
> 
> BUG: key ffff000005c080d8 has not been registered!
> ------------[ cut here ]------------
> DEBUG_LOCKS_WARN_ON(1)
> WARNING: CPU: 1 PID: 1080 at kernel/locking/lockdep.c:4895 
> lockdep_init_map_type+0x1cc/0x284
> Modules linked in: ipv6
> CPU: 1 PID: 1080 Comm: cgmanager Not tainted 6.10.0-rc3+ #1011
> Hardware name: linux,dummy-virt (DT)
> pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> pc : lockdep_init_map_type+0x1cc/0x284
> lr : lockdep_init_map_type+0x1cc/0x284
> ...
> Call trace:
>   lockdep_init_map_type+0x1cc/0x284
>   __kernfs_create_file+0x7c/0x138
>   cgroup_addrm_files+0x170/0x360
>   css_populate_dir+0x70/0x174
>   cgroup_apply_control_enable+0x128/0x378
>   rebind_subsystems+0x384/0x504
>   cgroup_setup_root+0x224/0x420
>   cgroup1_get_tree+0x248/0x36c
>   vfs_get_tree+0x28/0xe8
>   path_mount+0x3e8/0xb78
>   __arm64_sys_mount+0x1f0/0x2dc
>   invoke_syscall+0x48/0x118
>   el0_svc_common.constprop.0+0x40/0xe8
>   do_el0_svc_compat+0x20/0x3c
>   el0_svc_compat+0x44/0xe0
>   el0t_32_sync_handler+0x98/0x148
>   el0t_32_sync+0x194/0x198
> irq event stamp: 8225
> hardirqs last  enabled at (8225): [<ffff800080136134>] 
> console_unlock+0x164/0x190
> hardirqs last disabled at (8224): [<ffff800080136120>] 
> console_unlock+0x150/0x190
> softirqs last  enabled at (8214): [<ffff8000800ae1f4>] 
> handle_softirqs+0x4dc/0x4f4
> softirqs last disabled at (8207): [<ffff8000800105d4>] 
> __do_softirq+0x14/0x20
> ---[ end trace 0000000000000000 ]---
> 
> It looks that something is not properly intialized. Reverting $subject 
> on top of linux-next fixes this issue.

Yes, the root cause is that the cft->lockdep_key has not been registered
proactively when the CONFIG_DEBUG_LOCK_ALLOC is enabled.

Would you please try the following patch?

https://lore.kernel.org/all/20240618071922.2127289-1-xiujianfeng@huawei.com/

> 
> I've used defconfig with some debug options enabled and some drivers 
> compiled-in (if this matters):
> 
> make ARCH=arm64 defconfig
> 
> ./scripts/config -e BLK_DEV_RAM --set-val BLK_DEV_RAM_COUNT 4 --set-val 
> BLK_DEV_RAM_SIZE 81920 --set-val CMA_SIZE_MBYTES 96 -e PROVE_LOCKING -e 
> DEBUG_ATOMIC_SLEEP -e STAGING -e I2C_GPIO -e PM_DEBUG -e 
> PM_ADVANCED_DEBUG -e USB_GADGET -e USB_ETH -e CONFIG_DEVFREQ_THERMAL -e 
> CONFIG_BRCMFMAC_PCIE -e CONFIG_NFC -d ARCH_SUNXI -d ARCH_ALPINE -d 
> DRM_NOUVEAU -d ARCH_BCM_IPROC -d ARCH_BERLIN -d ARCH_BRCMSTB -d 
> ARCH_LAYERSCAPE -d ARCH_LG1K -d ARCH_HISI -d ARCH_MEDIATEK -d ARCH_MVEBU 
> -d ARCH_SEATTLE -d ARCH_SYNQUACER -d ARCH_RENESAS -d ARCH_STRATIX10 -d 
> ARCH_TEGRA -d ARCH_SPRD -d ARCH_THUNDER -d ARCH_THUNDER2 -d 
> ARCH_UNIPHIER -d ARCH_XGENE -d ARCH_ZX -d ARCH_ZYNQMP -d HIBERNATION -d 
> CLK_SUNXI -d CONFIG_EFI -d CONFIG_TEE -e FW_CFG_SYSFS
> 
> 
>> ---
>>   include/linux/hugetlb.h |   5 --
>>   mm/hugetlb_cgroup.c     | 163 +++++-----------------------------------
>>   2 files changed, 17 insertions(+), 151 deletions(-)
>>
>> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
>> index 279aca379b95..a951c0d06061 100644
>> --- a/include/linux/hugetlb.h
>> +++ b/include/linux/hugetlb.h
>> @@ -686,11 +686,6 @@ struct hstate {
>>   	unsigned int nr_huge_pages_node[MAX_NUMNODES];
>>   	unsigned int free_huge_pages_node[MAX_NUMNODES];
>>   	unsigned int surplus_huge_pages_node[MAX_NUMNODES];
>> -#ifdef CONFIG_CGROUP_HUGETLB
>> -	/* cgroup control files */
>> -	struct cftype cgroup_files_dfl[8];
>> -	struct cftype cgroup_files_legacy[10];
>> -#endif
>>   	char name[HSTATE_NAME_LEN];
>>   };
>>   
>> diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
>> index 43aae8f88d5f..2b899c4ae968 100644
>> --- a/mm/hugetlb_cgroup.c
>> +++ b/mm/hugetlb_cgroup.c
>> @@ -839,164 +839,26 @@ hugetlb_cgroup_cfttypes_init(struct hstate *h, struct cftype *cft,
>>   	}
>>   }
>>   
>> -static void __init __hugetlb_cgroup_file_dfl_init(int idx)
>> +static void __init __hugetlb_cgroup_file_dfl_init(struct hstate *h)
>>   {
>> -	char buf[32];
>> -	struct cftype *cft;
>> -	struct hstate *h = &hstates[idx];
>> +	int idx = hstate_index(h);
>>   
>>   	hugetlb_cgroup_cfttypes_init(h, dfl_files + idx * DFL_TMPL_SIZE,
>>   				     hugetlb_dfl_tmpl, DFL_TMPL_SIZE);
>> -
>> -	/* format the size */
>> -	mem_fmt(buf, sizeof(buf), huge_page_size(h));
>> -
>> -	/* Add the limit file */
>> -	cft = &h->cgroup_files_dfl[0];
>> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max", buf);
>> -	cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT);
>> -	cft->seq_show = hugetlb_cgroup_read_u64_max;
>> -	cft->write = hugetlb_cgroup_write_dfl;
>> -	cft->flags = CFTYPE_NOT_ON_ROOT;
>> -
>> -	/* Add the reservation limit file */
>> -	cft = &h->cgroup_files_dfl[1];
>> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.max", buf);
>> -	cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_LIMIT);
>> -	cft->seq_show = hugetlb_cgroup_read_u64_max;
>> -	cft->write = hugetlb_cgroup_write_dfl;
>> -	cft->flags = CFTYPE_NOT_ON_ROOT;
>> -
>> -	/* Add the current usage file */
>> -	cft = &h->cgroup_files_dfl[2];
>> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.current", buf);
>> -	cft->private = MEMFILE_PRIVATE(idx, RES_USAGE);
>> -	cft->seq_show = hugetlb_cgroup_read_u64_max;
>> -	cft->flags = CFTYPE_NOT_ON_ROOT;
>> -
>> -	/* Add the current reservation usage file */
>> -	cft = &h->cgroup_files_dfl[3];
>> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.current", buf);
>> -	cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_USAGE);
>> -	cft->seq_show = hugetlb_cgroup_read_u64_max;
>> -	cft->flags = CFTYPE_NOT_ON_ROOT;
>> -
>> -	/* Add the events file */
>> -	cft = &h->cgroup_files_dfl[4];
>> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.events", buf);
>> -	cft->private = MEMFILE_PRIVATE(idx, 0);
>> -	cft->seq_show = hugetlb_events_show;
>> -	cft->file_offset = offsetof(struct hugetlb_cgroup, events_file[idx]);
>> -	cft->flags = CFTYPE_NOT_ON_ROOT;
>> -
>> -	/* Add the events.local file */
>> -	cft = &h->cgroup_files_dfl[5];
>> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.events.local", buf);
>> -	cft->private = MEMFILE_PRIVATE(idx, 0);
>> -	cft->seq_show = hugetlb_events_local_show;
>> -	cft->file_offset = offsetof(struct hugetlb_cgroup,
>> -				    events_local_file[idx]);
>> -	cft->flags = CFTYPE_NOT_ON_ROOT;
>> -
>> -	/* Add the numa stat file */
>> -	cft = &h->cgroup_files_dfl[6];
>> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.numa_stat", buf);
>> -	cft->private = MEMFILE_PRIVATE(idx, 0);
>> -	cft->seq_show = hugetlb_cgroup_read_numa_stat;
>> -	cft->flags = CFTYPE_NOT_ON_ROOT;
>> -
>> -	/* NULL terminate the last cft */
>> -	cft = &h->cgroup_files_dfl[7];
>> -	memset(cft, 0, sizeof(*cft));
>> -
>> -	WARN_ON(cgroup_add_dfl_cftypes(&hugetlb_cgrp_subsys,
>> -				       h->cgroup_files_dfl));
>>   }
>>   
>> -static void __init __hugetlb_cgroup_file_legacy_init(int idx)
>> +static void __init __hugetlb_cgroup_file_legacy_init(struct hstate *h)
>>   {
>> -	char buf[32];
>> -	struct cftype *cft;
>> -	struct hstate *h = &hstates[idx];
>> +	int idx = hstate_index(h);
>>   
>>   	hugetlb_cgroup_cfttypes_init(h, legacy_files + idx * LEGACY_TMPL_SIZE,
>>   				     hugetlb_legacy_tmpl, LEGACY_TMPL_SIZE);
>> -
>> -	/* format the size */
>> -	mem_fmt(buf, sizeof(buf), huge_page_size(h));
>> -
>> -	/* Add the limit file */
>> -	cft = &h->cgroup_files_legacy[0];
>> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.limit_in_bytes", buf);
>> -	cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT);
>> -	cft->read_u64 = hugetlb_cgroup_read_u64;
>> -	cft->write = hugetlb_cgroup_write_legacy;
>> -
>> -	/* Add the reservation limit file */
>> -	cft = &h->cgroup_files_legacy[1];
>> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.limit_in_bytes", buf);
>> -	cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_LIMIT);
>> -	cft->read_u64 = hugetlb_cgroup_read_u64;
>> -	cft->write = hugetlb_cgroup_write_legacy;
>> -
>> -	/* Add the usage file */
>> -	cft = &h->cgroup_files_legacy[2];
>> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.usage_in_bytes", buf);
>> -	cft->private = MEMFILE_PRIVATE(idx, RES_USAGE);
>> -	cft->read_u64 = hugetlb_cgroup_read_u64;
>> -
>> -	/* Add the reservation usage file */
>> -	cft = &h->cgroup_files_legacy[3];
>> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.usage_in_bytes", buf);
>> -	cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_USAGE);
>> -	cft->read_u64 = hugetlb_cgroup_read_u64;
>> -
>> -	/* Add the MAX usage file */
>> -	cft = &h->cgroup_files_legacy[4];
>> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max_usage_in_bytes", buf);
>> -	cft->private = MEMFILE_PRIVATE(idx, RES_MAX_USAGE);
>> -	cft->write = hugetlb_cgroup_reset;
>> -	cft->read_u64 = hugetlb_cgroup_read_u64;
>> -
>> -	/* Add the MAX reservation usage file */
>> -	cft = &h->cgroup_files_legacy[5];
>> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.max_usage_in_bytes", buf);
>> -	cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_MAX_USAGE);
>> -	cft->write = hugetlb_cgroup_reset;
>> -	cft->read_u64 = hugetlb_cgroup_read_u64;
>> -
>> -	/* Add the failcntfile */
>> -	cft = &h->cgroup_files_legacy[6];
>> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.failcnt", buf);
>> -	cft->private = MEMFILE_PRIVATE(idx, RES_FAILCNT);
>> -	cft->write = hugetlb_cgroup_reset;
>> -	cft->read_u64 = hugetlb_cgroup_read_u64;
>> -
>> -	/* Add the reservation failcntfile */
>> -	cft = &h->cgroup_files_legacy[7];
>> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.failcnt", buf);
>> -	cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_FAILCNT);
>> -	cft->write = hugetlb_cgroup_reset;
>> -	cft->read_u64 = hugetlb_cgroup_read_u64;
>> -
>> -	/* Add the numa stat file */
>> -	cft = &h->cgroup_files_legacy[8];
>> -	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.numa_stat", buf);
>> -	cft->private = MEMFILE_PRIVATE(idx, 0);
>> -	cft->seq_show = hugetlb_cgroup_read_numa_stat;
>> -
>> -	/* NULL terminate the last cft */
>> -	cft = &h->cgroup_files_legacy[9];
>> -	memset(cft, 0, sizeof(*cft));
>> -
>> -	WARN_ON(cgroup_add_legacy_cftypes(&hugetlb_cgrp_subsys,
>> -					  h->cgroup_files_legacy));
>>   }
>>   
>> -static void __init __hugetlb_cgroup_file_init(int idx)
>> +static void __init __hugetlb_cgroup_file_init(struct hstate *h)
>>   {
>> -	__hugetlb_cgroup_file_dfl_init(idx);
>> -	__hugetlb_cgroup_file_legacy_init(idx);
>> +	__hugetlb_cgroup_file_dfl_init(h);
>> +	__hugetlb_cgroup_file_legacy_init(h);
>>   }
>>   
>>   static void __init __hugetlb_cgroup_file_pre_init(void)
>> @@ -1011,13 +873,22 @@ static void __init __hugetlb_cgroup_file_pre_init(void)
>>   	BUG_ON(!legacy_files);
>>   }
>>   
>> +static void __init __hugetlb_cgroup_file_post_init(void)
>> +{
>> +	WARN_ON(cgroup_add_dfl_cftypes(&hugetlb_cgrp_subsys,
>> +				       dfl_files));
>> +	WARN_ON(cgroup_add_legacy_cftypes(&hugetlb_cgrp_subsys,
>> +					  legacy_files));
>> +}
>> +
>>   void __init hugetlb_cgroup_file_init(void)
>>   {
>>   	struct hstate *h;
>>   
>>   	__hugetlb_cgroup_file_pre_init();
>>   	for_each_hstate(h)
>> -		__hugetlb_cgroup_file_init(hstate_index(h));
>> +		__hugetlb_cgroup_file_init(h);
>> +	__hugetlb_cgroup_file_post_init();
>>   }
>>   
>>   /*
> 
> Best regards