RE: [PATCH net-next 1/2] net: Keep sk->sk_forward_alloc as a proper size

Zhang, Cathy
2023-05-12T03:23:56Z

Remove the invalid mail addr added unintentionally.

> -----Original Message-----
> From: Zhang, Cathy
> Sent: Friday, May 12, 2023 10:39 AM
> To: Shakeel Butt <shakeelb@google.com>; Zhang@google.com
> Cc: Eric Dumazet <edumazet@google.com>; Linux MM <linux-
> mm@kvack.org>; Cgroups <cgroups@vger.kernel.org>; Paolo Abeni
> <pabeni@redhat.com>; davem@davemloft.net; kuba@kernel.org;
> Brandeburg@google.com; Brandeburg, Jesse <jesse.brandeburg@intel.com>;
> Srinivas@google.com; Srinivas, Suresh <suresh.srinivas@intel.com>;
> Chen@google.com; Chen, Tim C <tim.c.chen@intel.com>; You@google.com;
> You, Lizhen <Lizhen.You@intel.com>; eric.dumazet@gmail.com;
> netdev@vger.kernel.org
> Subject: RE: [PATCH net-next 1/2] net: Keep sk->sk_forward_alloc as a proper
> size
>
>
>
> > -----Original Message-----
> > From: Shakeel Butt <shakeelb@google.com>
> > Sent: Friday, May 12, 2023 5:19 AM
> > To: Zhang@google.com; Zhang, Cathy <cathy.zhang@intel.com>
> > Cc: Eric Dumazet <edumazet@google.com>; Linux MM <linux-
> > mm@kvack.org>; Cgroups <cgroups@vger.kernel.org>; Paolo Abeni
> > <pabeni@redhat.com>; davem@davemloft.net; kuba@kernel.org;
> > Brandeburg@google.com; Brandeburg, Jesse
> <jesse.brandeburg@intel.com>;
> > Srinivas@google.com; Srinivas, Suresh <suresh.srinivas@intel.com>;
> > Chen@google.com; Chen, Tim C <tim.c.chen@intel.com>;
> You@google.com;
> > You, Lizhen <lizhen.you@intel.com>; eric.dumazet@gmail.com;
> > netdev@vger.kernel.org
> > Subject: Re: [PATCH net-next 1/2] net: Keep sk->sk_forward_alloc as a
> > proper size
> >
> > On Thu, May 11, 2023 at 09:26:46AM +0000, Zhang, Cathy wrote:
> > >
> > [...]
> > >
> > > 8.98% mc-worker [kernel.vmlinux] [k] page_counter_cancel
> > > |
> > > --8.97%--page_counter_cancel
> > > |
> > > --8.97%--page_counter_uncharge
> > > drain_stock
> > > __refill_stock
> > > refill_stock
> > > |
> > > --8.91%--try_charge_memcg
> > > mem_cgroup_charge_skmem
> >
> > I do want to understand for above which specific condition in
> > __refill_stock is causing to drain stock in the charge code path. Can
> > you please re-run and profile your test with following code snippet
> > (or use any other mechanism which can answer the question)?
> >
> > From f1d91043f21f4b29717c78615b374d79fc021d1f Mon Sep 17 00:00:00
> > 2001
> > From: Shakeel Butt <shakeelb@google.com>
> > Date: Thu, 11 May 2023 20:00:19 +0000
> > Subject: [PATCH] Debug drain on charging.
> >
> > ---
> > mm/memcontrol.c | 14 ++++++++++++--
> > 1 file changed, 12 insertions(+), 2 deletions(-)
> >
> > diff --git a/mm/memcontrol.c b/mm/memcontrol.c index
> > d31fb1e2cb33..4c1c3d90a4a3 100644
> > --- a/mm/memcontrol.c
> > +++ b/mm/memcontrol.c
> > @@ -2311,6 +2311,16 @@ static void drain_local_stock(struct
> > work_struct
> > *dummy)
> > obj_cgroup_put(old);
> > }
> >
> > +static noinline void drain_stock_1(struct memcg_stock_pcp *stock) {
> > + drain_stock(stock);
> > +}
> > +
> > +static noinline void drain_stock_2(struct memcg_stock_pcp *stock) {
> > + drain_stock(stock);
> > +}
> > +
> > /*
> > * Cache charges(val) to local per_cpu area.
> > * This will be consumed by consume_stock() function, later.
> > @@ -2321,14 +2331,14 @@ static void __refill_stock(struct mem_cgroup
> > *memcg, unsigned int nr_pages)
> >
> > stock = this_cpu_ptr(&memcg_stock);
> > if (READ_ONCE(stock->cached) != memcg) { /* reset if necessary */
> > - drain_stock(stock);
> > + drain_stock_1(stock);
> > css_get(&memcg->css);
> > WRITE_ONCE(stock->cached, memcg);
> > }
> > stock->nr_pages += nr_pages;
> >
> > if (stock->nr_pages > MEMCG_CHARGE_BATCH)
> > - drain_stock(stock);
> > + drain_stock_2(stock);
> > }
> >
> > static void refill_stock(struct mem_cgroup *memcg, unsigned int
> > nr_pages)
> > --
> > 2.40.1.606.ga4b1b128d6-goog
>
> Hi Shakeel,
>
> Run with the temp change you provided, the output shows it comes to
> drain_stock_1(), Here is the call trace:
>
> 8.96% mc-worker [kernel.vmlinux] [k] page_counter_cancel
> |
> --8.95%--page_counter_cancel
> |
> --8.95%--page_counter_uncharge
> drain_stock_1
> __refill_stock
> refill_stock
> |
> --8.88%--try_charge_memcg
> mem_cgroup_charge_skmem
> |
> --8.87%--__sk_mem_raise_allocated
> __sk_mem_schedule
> |
> |--5.37%--tcp_try_rmem_schedule
> | tcp_data_queue
> | tcp_rcv_established
> | tcp_v4_do_rcv