memcg: move v1 only percpu stats in separate struct

Patch series "memcg: further decouple v1 code from v2".

Some of the v1 code is still in v2 code base due to v1 fields in the
struct memcg_vmstats_percpu.  This field decouples those fileds from v2
struct and move all the related code into v1 only code base.


This patch (of 7):

At the moment struct memcg_vmstats_percpu contains two v1 only fields
which consumes memory even when CONFIG_MEMCG_V1 is not enabled.  In
addition there are v1 only functions accessing them and are in the main
memcontrol source file and can not be moved to v1 only source file due to
these fields.  Let's move these fields into their own struct.  Later
patches will move the functions accessing them to v1 source file and only
allocate these fields when CONFIG_MEMCG_V1 is enabled.

Link: https://lkml.kernel.org/r/20240815050453.1298138-1-shakeel.butt@linux.dev
Link: https://lkml.kernel.org/r/20240815050453.1298138-2-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: T.J. Mercier <tjmercier@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 9 insertions, 9 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 96f85fd0e5b3..36ec28d3d25e 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -477,10 +477,6 @@ struct memcg_vmstats_percpu {
 	/* Delta calculation for lockless upward propagation */
 	long			state_prev[MEMCG_VMSTAT_SIZE];
 	unsigned long		events_prev[NR_MEMCG_EVENTS];
-
-	/* Cgroup1: threshold notifications & softlimit tree updates */
-	unsigned long		nr_page_events;
-	unsigned long		targets[MEM_CGROUP_NTARGETS];
 } ____cacheline_aligned;
 
 struct memcg_vmstats {
@@ -857,7 +853,7 @@ void mem_cgroup_charge_statistics(struct mem_cgroup *memcg, int nr_pages)
 		nr_pages = -nr_pages; /* for event */
 	}
 
-	__this_cpu_add(memcg->vmstats_percpu->nr_page_events, nr_pages);
+	__this_cpu_add(memcg->events_percpu->nr_page_events, nr_pages);
 }
 
 bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
@@ -865,8 +861,8 @@ bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
 {
 	unsigned long val, next;
 
-	val = __this_cpu_read(memcg->vmstats_percpu->nr_page_events);
-	next = __this_cpu_read(memcg->vmstats_percpu->targets[target]);
+	val = __this_cpu_read(memcg->events_percpu->nr_page_events);
+	next = __this_cpu_read(memcg->events_percpu->targets[target]);
 	/* from time_after() in jiffies.h */
 	if ((long)(next - val) < 0) {
 		switch (target) {
@@ -879,7 +875,7 @@ bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
 		default:
 			break;
 		}
-		__this_cpu_write(memcg->vmstats_percpu->targets[target], next);
+		__this_cpu_write(memcg->events_percpu->targets[target], next);
 		return true;
 	}
 	return false;
@@ -3477,6 +3473,7 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg)
 
 	for_each_node(node)
 		free_mem_cgroup_per_node_info(memcg, node);
+	memcg1_free_events(memcg);
 	kfree(memcg->vmstats);
 	free_percpu(memcg->vmstats_percpu);
 	kfree(memcg);
@@ -3517,6 +3514,9 @@ static struct mem_cgroup *mem_cgroup_alloc(struct mem_cgroup *parent)
 	if (!memcg->vmstats_percpu)
 		goto fail;
 
+	if (!memcg1_alloc_events(memcg))
+		goto fail;
+
 	for_each_possible_cpu(cpu) {
 		if (parent)
 			pstatc = per_cpu_ptr(parent->vmstats_percpu, cpu);
@@ -4631,7 +4631,7 @@ static void uncharge_batch(const struct uncharge_gather *ug)
 
 	local_irq_save(flags);
 	__count_memcg_events(ug->memcg, PGPGOUT, ug->pgpgout);
-	__this_cpu_add(ug->memcg->vmstats_percpu->nr_page_events, ug->nr_memory);
+	__this_cpu_add(ug->memcg->events_percpu->nr_page_events, ug->nr_memory);
 	memcg1_check_events(ug->memcg, ug->nid);
 	local_irq_restore(flags);