On Thu, Feb 24, 2022 at 6:52 PM Shakeel Butt <shakeelb@xxxxxxxxxx> wrote:
>
> On Thu, Feb 24, 2022 at 10:00:55AM -0800, Shakeel Butt wrote:
> > On Thu, Feb 24, 2022 at 9:34 AM Daniel Dao <dqminh@xxxxxxxxxxxxxx> wrote:
> [...]
> > Anyways I am thinking of introducing mem_cgroup_flush_stats_asyn()
> > which will schedule flush_memcg_stats_dwork() without delay. Let me
> > prepare the patch based on 5.15-stable for you to test.
>
>
> Can you please try the following patch and let me the results?
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index d9b8df5ef212..cd732d7e00ca 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -1002,6 +1002,7 @@ static inline unsigned long
> lruvec_page_state_local(struct lruvec *lruvec,
> }
>
> void mem_cgroup_flush_stats(void);
> +void mem_cgroup_flush_stats_async(void);
>
> void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item
> idx,
> int val);
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 32ba963ebf2e..0f298cbd4763 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -682,6 +682,14 @@ void mem_cgroup_flush_stats(void)
> __mem_cgroup_flush_stats();
> }
>
> +void mem_cgroup_flush_stats_aync(void)
> +{
> + if (atomic_read(&stats_flush_threshold) > num_online_cpus()) {
> + mod_delayed_work(system_unbound_wq, &stats_flush_dwork, 0);
> + atomic_set(&stats_flush_threshold, 0);
> + }
> +}
> +
> static void flush_memcg_stats_dwork(struct work_struct *w)
> {
> __mem_cgroup_flush_stats();
> diff --git a/mm/workingset.c b/mm/workingset.c
> index d5b81e4f4cbe..86d43bfc5c63 100644
> --- a/mm/workingset.c
> +++ b/mm/workingset.c
> @@ -352,7 +352,7 @@ void workingset_refault(struct page *page, void *shadow)
>
> inc_lruvec_state(lruvec, WORKINGSET_REFAULT_BASE + file);
>
> - mem_cgroup_flush_stats();
> + mem_cgroup_flush_stats_async();
> /*
> * Compare the distance to the existing workingset size. We
> * don't activate pages that couldn't stay resident even if
I think this looks good so far. Some stats:
1) More time spent in flush_memcg_stats_dwork
$ sudo /usr/share/bcc/tools/funclatency -d 60 flush_memcg_stats_dwork
Tracing 1 functions for "flush_memcg_stats_dwork"... Hit Ctrl-C to end.
nsecs : count distribution
0 -> 1 : 0 | |
2 -> 3 : 0 | |
4 -> 7 : 0 | |
8 -> 15 : 0 | |
16 -> 31 : 0 | |
32 -> 63 : 0 | |
64 -> 127 : 0 | |
128 -> 255 : 0 | |
256 -> 511 : 21 | |
512 -> 1023 : 115 | |
1024 -> 2047 : 47 | |
2048 -> 4095 : 86 | |
4096 -> 8191 : 48 | |
8192 -> 16383 : 2 | |
16384 -> 32767 : 2 | |
32768 -> 65535 : 1 | |
65536 -> 131071 : 52 | |
131072 -> 262143 : 400 |** |
262144 -> 524287 : 2172 |**************** |
524288 -> 1048575 : 4193 |******************************* |
1048576 -> 2097151 : 5357 |****************************************|
2097152 -> 4194303 : 1834 |************* |
4194304 -> 8388607 : 485 |*** |
8388608 -> 16777215 : 3 | |
avg = 1346983 nsecs, total: 19959597708 nsecs, count: 14818
2) Less time spent in workingset_refault
~$ sudo /usr/share/bcc/tools/funclatency -d 60 workingset_refault
Tracing 1 functions for "workingset_refault"... Hit Ctrl-C to end.
nsecs : count distribution
0 -> 1 : 0 | |
2 -> 3 : 0 | |
4 -> 7 : 0 | |
8 -> 15 : 0 | |
16 -> 31 : 0 | |
32 -> 63 : 0 | |
64 -> 127 : 0 | |
128 -> 255 : 0 | |
256 -> 511 : 10318 |****************************************|
512 -> 1023 : 2877 |*********** |
1024 -> 2047 : 1089 |**** |
2048 -> 4095 : 4785 |****************** |
4096 -> 8191 : 4528 |***************** |
8192 -> 16383 : 1270 |**** |
16384 -> 32767 : 82 | |
32768 -> 65535 : 80 | |
65536 -> 131071 : 20 | |
131072 -> 262143 : 2 | |
262144 -> 524287 : 0 | |
524288 -> 1048575 : 1 | |
avg = 2705 nsecs, total: 67782139 nsecs, count: 25052
