mm: vmscan: do not scan anon pages if memcg swap limit is hit

[linux-2.6-block.git] / mm / memcontrol.c

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 1ff552e3722b0eb8eafb609d40ad3a7cccd18311..bcb38718e174f1af77f362f584e049762ba552f7 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5748,6 +5748,19 @@ void mem_cgroup_uncharge_swap(swp_entry_t entry)
        rcu_read_unlock();
 }
 
+long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
+{
+       long nr_swap_pages = get_nr_swap_pages();
+
+       if (!do_swap_account || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
+               return nr_swap_pages;
+       for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg))
+               nr_swap_pages = min_t(long, nr_swap_pages,
+                                     READ_ONCE(memcg->swap.limit) -
+                                     page_counter_read(&memcg->swap));
+       return nr_swap_pages;
+}
+
 /* for remember boot option*/
 #ifdef CONFIG_MEMCG_SWAP_ENABLED
 static int really_do_swap_account __initdata = 1;