[PATCH 2/2 v2] memcg: use memcg flush tracepoint

JP Kobryn
2024-10-26T00:48:37Z

Make use of the memcg flush tracepoint within memcontrol.

Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
---
mm/memcontrol.c | 22 +++++++++++++---------
1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 18c3f513d766..c3d6163aaa1c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -588,8 +588,16 @@ static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val)
}
}

-static void do_flush_stats(struct mem_cgroup *memcg)
+static void __mem_cgroup_flush_stats(struct mem_cgroup *memcg, bool force)
{
+ bool needs_flush = memcg_vmstats_needs_flush(memcg->vmstats);
+
+ trace_memcg_flush_stats(memcg, atomic64_read(&memcg->vmstats->stats_updates),
+ force, needs_flush);
+
+ if (!force && !needs_flush)
+ return;
+
if (mem_cgroup_is_root(memcg))
WRITE_ONCE(flush_last_time, jiffies_64);

@@ -613,8 +621,7 @@ void mem_cgroup_flush_stats(struct mem_cgroup *memcg)
if (!memcg)
memcg = root_mem_cgroup;

- if (memcg_vmstats_needs_flush(memcg->vmstats))
- do_flush_stats(memcg);
+ __mem_cgroup_flush_stats(memcg, false);
}

void mem_cgroup_flush_stats_ratelimited(struct mem_cgroup *memcg)
@@ -630,7 +637,7 @@ static void flush_memcg_stats_dwork(struct work_struct *w)
* Deliberately ignore memcg_vmstats_needs_flush() here so that flushing
* in latency-sensitive paths is as cheap as possible.
*/
- do_flush_stats(root_mem_cgroup);
+ __mem_cgroup_flush_stats(root_mem_cgroup, true);
queue_delayed_work(system_unbound_wq, &stats_flush_dwork, FLUSH_TIME);
}

@@ -5281,11 +5288,8 @@ bool obj_cgroup_may_zswap(struct obj_cgroup *objcg)
break;
}

- /*
- * mem_cgroup_flush_stats() ignores small changes. Use
- * do_flush_stats() directly to get accurate stats for charging.
- */
- do_flush_stats(memcg);
+ /* Force flush to get accurate stats for charging */
+ __mem_cgroup_flush_stats(memcg, true);
pages = memcg_page_state(memcg, MEMCG_ZSWAP_B) / PAGE_SIZE;
if (pages < max)
continue;
--
2.47.0