From 20ccbd89afe425eda2de48a9a701916d98c1f306 Mon Sep 17 00:00:00 2001 From: Shakeel Butt Date: Thu, 25 Dec 2025 15:21:14 -0800 Subject: [PATCH] mm/vmscan: use cgroup ID instead of private memcg ID in lru_gen interface The LRU gen debugfs interface was using the internal private memcg ID which is meant for tracking kernel objects that outlive their cgroup. Switch to using the public cgroup ID instead. Link: https://lkml.kernel.org/r/20251225232116.294540-7-shakeel.butt@linux.dev Signed-off-by: Shakeel Butt Acked-by: Michal Hocko Cc: Axel Rasmussen Cc: Dave Chinner Cc: David Hildenbrand Cc: Johannes Weiner Cc: Lorenzo Stoakes Cc: Muchun Song Cc: Qi Zheng Cc: Roman Gushchin Cc: SeongJae Park Cc: Wei Xu Cc: Yuanchu Xie Signed-off-by: Andrew Morton --- mm/vmscan.c | 19 ++++++------------- 1 file changed, 6 insertions(+), 13 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 619691aa43938..b87baf3fc77f2 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -5416,7 +5416,7 @@ static int lru_gen_seq_show(struct seq_file *m, void *v) if (memcg) cgroup_path(memcg->css.cgroup, m->private, PATH_MAX); #endif - seq_printf(m, "memcg %5hu %s\n", mem_cgroup_id(memcg), path); + seq_printf(m, "memcg %llu %s\n", mem_cgroup_ino(memcg), path); } seq_printf(m, " node %5d\n", nid); @@ -5501,7 +5501,7 @@ static int run_eviction(struct lruvec *lruvec, unsigned long seq, struct scan_co return -EINTR; } -static int run_cmd(char cmd, int memcg_id, int nid, unsigned long seq, +static int run_cmd(char cmd, u64 memcg_id, int nid, unsigned long seq, struct scan_control *sc, int swappiness, unsigned long opt) { struct lruvec *lruvec; @@ -5512,19 +5512,12 @@ static int run_cmd(char cmd, int memcg_id, int nid, unsigned long seq, return -EINVAL; if (!mem_cgroup_disabled()) { - rcu_read_lock(); - - memcg = mem_cgroup_from_id(memcg_id); - if (!mem_cgroup_tryget(memcg)) - memcg = NULL; - - rcu_read_unlock(); - + memcg = mem_cgroup_get_from_ino(memcg_id); if (!memcg) return -EINVAL; } - if (memcg_id != mem_cgroup_id(memcg)) + if (memcg_id != mem_cgroup_ino(memcg)) goto done; sc->target_mem_cgroup = memcg; @@ -5591,7 +5584,7 @@ static ssize_t lru_gen_seq_write(struct file *file, const char __user *src, int n; int end; char cmd, swap_string[5]; - unsigned int memcg_id; + u64 memcg_id; unsigned int nid; unsigned long seq; unsigned int swappiness; @@ -5601,7 +5594,7 @@ static ssize_t lru_gen_seq_write(struct file *file, const char __user *src, if (!*cur) continue; - n = sscanf(cur, "%c %u %u %lu %n %4s %n %lu %n", &cmd, &memcg_id, &nid, + n = sscanf(cur, "%c %llu %u %lu %n %4s %n %lu %n", &cmd, &memcg_id, &nid, &seq, &end, swap_string, &end, &opt, &end); if (n < 4 || cur[end]) { err = -EINVAL; -- 2.47.3