memcg: move v1 events and statistics code to v1 file

Currently the common code path for charge commit, swapout and batched
uncharge are executing v1 only code which is completely useless for the v2
deployments where CONFIG_MEMCG_V1 is disabled.  In addition, it is mucking
with IRQs which might be slow on some architectures.  Let's move all of
this code to v1 only code and remove them from v2 only deployments.

Link: https://lkml.kernel.org/r/20240815050453.1298138-5-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: T.J. Mercier <tjmercier@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 37 insertions, 0 deletions

diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c
index 7317f2ce8876..540b45ab4b26 100644
--- a/mm/memcontrol-v1.c
+++ b/mm/memcontrol-v1.c
@@ -1502,6 +1502,43 @@ void memcg1_check_events(struct mem_cgroup *memcg, int nid)
 	}
 }
 
+void memcg1_commit_charge(struct folio *folio, struct mem_cgroup *memcg)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	memcg1_charge_statistics(memcg, folio_nr_pages(folio));
+	memcg1_check_events(memcg, folio_nid(folio));
+	local_irq_restore(flags);
+}
+
+void memcg1_swapout(struct folio *folio, struct mem_cgroup *memcg)
+{
+	/*
+	 * Interrupts should be disabled here because the caller holds the
+	 * i_pages lock which is taken with interrupts-off. It is
+	 * important here to have the interrupts disabled because it is the
+	 * only synchronisation we have for updating the per-CPU variables.
+	 */
+	preempt_disable_nested();
+	VM_WARN_ON_IRQS_ENABLED();
+	memcg1_charge_statistics(memcg, -folio_nr_pages(folio));
+	preempt_enable_nested();
+	memcg1_check_events(memcg, folio_nid(folio));
+}
+
+void memcg1_uncharge_batch(struct mem_cgroup *memcg, unsigned long pgpgout,
+			   unsigned long nr_memory, int nid)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__count_memcg_events(memcg, PGPGOUT, pgpgout);
+	__this_cpu_add(memcg->events_percpu->nr_page_events, nr_memory);
+	memcg1_check_events(memcg, nid);
+	local_irq_restore(flags);
+}
+
 static int compare_thresholds(const void *a, const void *b)
 {
 	const struct mem_cgroup_threshold *_a = a;