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From: Xiu Jianfeng <xiujianfeng@huawei.com>
To: <akpm@linux-foundation.org>, <muchun.song@linux.dev>
CC: <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>
Subject: [PATCH v2 -next 1/3] mm/hugetlb_cgroup: identify the legacy using cgroup_subsys_on_dfl()
Date: Wed, 5 Jun 2024 07:01:31 +0000
Message-ID: <20240605070133.1941677-2-xiujianfeng@huawei.com>
In-Reply-To: <20240605070133.1941677-1-xiujianfeng@huawei.com>
References: <20240605070133.1941677-1-xiujianfeng@huawei.com>
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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 array of the comming patch.

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