mm: memcg: guard memcg1-specific fields accesses in mm/memcontrol.c

There are only few memcg1-specific struct mem_cgroup's members accesses
left in mm/memcontrol.c.  Let's guard them with the CONFIG_MEMCG_V1 config
option.

Link: https://lkml.kernel.org/r/20240628210317.272856-6-roman.gushchin@linux.dev
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d1ae097f0351e4228797a7226b92cbff62947518..2df5782eb0ac439c52ac28a849db01c3bfca9325 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3637,20 +3637,23 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
        page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX);
        if (parent) {
                WRITE_ONCE(memcg->swappiness, mem_cgroup_swappiness(parent));
-               WRITE_ONCE(memcg->oom_kill_disable, READ_ONCE(parent->oom_kill_disable));
 
                page_counter_init(&memcg->memory, &parent->memory);
                page_counter_init(&memcg->swap, &parent->swap);
+#ifdef CONFIG_MEMCG_V1
+               WRITE_ONCE(memcg->oom_kill_disable, READ_ONCE(parent->oom_kill_disable));
                page_counter_init(&memcg->kmem, &parent->kmem);
                page_counter_init(&memcg->tcpmem, &parent->tcpmem);
+#endif
        } else {
                init_memcg_stats();
                init_memcg_events();
                page_counter_init(&memcg->memory, NULL);
                page_counter_init(&memcg->swap, NULL);
+#ifdef CONFIG_MEMCG_V1
                page_counter_init(&memcg->kmem, NULL);
                page_counter_init(&memcg->tcpmem, NULL);
-
+#endif
                root_mem_cgroup = memcg;
                return &memcg->css;
        }
@@ -3785,8 +3788,10 @@ static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
 
        page_counter_set_max(&memcg->memory, PAGE_COUNTER_MAX);
        page_counter_set_max(&memcg->swap, PAGE_COUNTER_MAX);
+#ifdef CONFIG_MEMCG_V1
        page_counter_set_max(&memcg->kmem, PAGE_COUNTER_MAX);
        page_counter_set_max(&memcg->tcpmem, PAGE_COUNTER_MAX);
+#endif
        page_counter_set_min(&memcg->memory, 0);
        page_counter_set_low(&memcg->memory, 0);
        page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX);