From: Soheil Hassas Yeganeh <soheil@google.com>
To: Shakeel Butt <shakeelb@google.com>
Cc: "Johannes Weiner" <hannes@cmpxchg.org>,
"Michal Hocko" <mhocko@kernel.org>,
"Roman Gushchin" <roman.gushchin@linux.dev>,
"Muchun Song" <songmuchun@bytedance.com>,
"Michal Koutný" <mkoutny@suse.com>,
"Eric Dumazet" <edumazet@google.com>,
"Feng Tang" <feng.tang@intel.com>,
"Oliver Sang" <oliver.sang@intel.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
lkp@lists.01.org, cgroups@vger.kernel.org,
linux-mm <linux-mm@kvack.org>, netdev <netdev@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/3] mm: page_counter: remove unneeded atomic ops for low/min
Date: Sun, 21 Aug 2022 20:20:14 -0400 [thread overview]
Message-ID: <CACSApvbSnCN8Fy1E3KyhkBDF=_h4vg==eoJGzM1Njf0ArX+zcg@mail.gmail.com> (raw)
In-Reply-To: <20220822001737.4120417-2-shakeelb@google.com>
On Sun, Aug 21, 2022 at 8:17 PM Shakeel Butt <shakeelb@google.com> wrote:
>
> For cgroups using low or min protections, the function
> propagate_protected_usage() was doing an atomic xchg() operation
> irrespectively. It only needs to do that operation if the new value of
> protection is different from older one. This patch does that.
>
> To evaluate the impact of this optimization, on a 72 CPUs machine, we
> ran the following workload in a three level of cgroup hierarchy with top
> level having min and low setup appropriately. More specifically
> memory.min equal to size of netperf binary and memory.low double of
> that.
>
> $ netserver -6
> # 36 instances of netperf with following params
> $ netperf -6 -H ::1 -l 60 -t TCP_SENDFILE -- -m 10K
>
> Results (average throughput of netperf):
> Without (6.0-rc1) 10482.7 Mbps
> With patch 14542.5 Mbps (38.7% improvement)
>
> With the patch, the throughput improved by 38.7%
>
> Signed-off-by: Shakeel Butt <shakeelb@google.com>
> Reported-by: kernel test robot <oliver.sang@intel.com>
Nice speed up!
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
> ---
> mm/page_counter.c | 13 ++++++-------
> 1 file changed, 6 insertions(+), 7 deletions(-)
>
> diff --git a/mm/page_counter.c b/mm/page_counter.c
> index eb156ff5d603..47711aa28161 100644
> --- a/mm/page_counter.c
> +++ b/mm/page_counter.c
> @@ -17,24 +17,23 @@ static void propagate_protected_usage(struct page_counter *c,
> unsigned long usage)
> {
> unsigned long protected, old_protected;
> - unsigned long low, min;
> long delta;
>
> if (!c->parent)
> return;
>
> - min = READ_ONCE(c->min);
> - if (min || atomic_long_read(&c->min_usage)) {
> - protected = min(usage, min);
> + protected = min(usage, READ_ONCE(c->min));
> + old_protected = atomic_long_read(&c->min_usage);
> + if (protected != old_protected) {
> old_protected = atomic_long_xchg(&c->min_usage, protected);
> delta = protected - old_protected;
> if (delta)
> atomic_long_add(delta, &c->parent->children_min_usage);
> }
>
> - low = READ_ONCE(c->low);
> - if (low || atomic_long_read(&c->low_usage)) {
> - protected = min(usage, low);
> + protected = min(usage, READ_ONCE(c->low));
> + old_protected = atomic_long_read(&c->low_usage);
> + if (protected != old_protected) {
> old_protected = atomic_long_xchg(&c->low_usage, protected);
> delta = protected - old_protected;
> if (delta)
> --
> 2.37.1.595.g718a3a8f04-goog
>
next prev parent reply other threads:[~2022-08-22 0:20 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-22 0:17 [PATCH 0/3] memcg: optimizatize charge codepath Shakeel Butt
2022-08-22 0:17 ` [PATCH 1/3] mm: page_counter: remove unneeded atomic ops for low/min Shakeel Butt
2022-08-22 0:20 ` Soheil Hassas Yeganeh [this message]
2022-08-22 2:39 ` Feng Tang
2022-08-22 9:55 ` Michal Hocko
2022-08-22 10:18 ` Michal Hocko
2022-08-22 14:55 ` Shakeel Butt
2022-08-22 15:20 ` Michal Hocko
2022-08-22 16:06 ` Shakeel Butt
2022-08-23 9:42 ` Michal Hocko
2022-08-22 18:23 ` Roman Gushchin
2022-08-22 0:17 ` [PATCH 2/3] mm: page_counter: rearrange struct page_counter fields Shakeel Butt
2022-08-22 0:24 ` Soheil Hassas Yeganeh
2022-08-22 4:55 ` Shakeel Butt
2022-08-22 13:06 ` Soheil Hassas Yeganeh
2022-08-22 2:10 ` Feng Tang
2022-08-22 4:59 ` Shakeel Butt
2022-08-22 10:23 ` Michal Hocko
2022-08-22 15:06 ` Shakeel Butt
2022-08-22 15:15 ` Michal Hocko
2022-08-22 16:04 ` Shakeel Butt
2022-08-22 18:27 ` Roman Gushchin
2022-08-22 0:17 ` [PATCH 3/3] memcg: increase MEMCG_CHARGE_BATCH to 64 Shakeel Butt
2022-08-22 0:24 ` Soheil Hassas Yeganeh
2022-08-22 2:30 ` Feng Tang
2022-08-22 10:47 ` Michal Hocko
2022-08-22 15:09 ` Shakeel Butt
2022-08-22 15:22 ` Michal Hocko
2022-08-22 16:07 ` Shakeel Butt
2022-08-22 18:37 ` Roman Gushchin
2022-08-22 19:34 ` Michal Hocko
2022-08-23 2:22 ` Roman Gushchin
2022-08-23 4:49 ` Michal Hocko
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