Messages in this thread | | | From | Eric Dumazet <> | Date | Mon, 19 Jun 2023 12:08:07 +0200 | Subject | Re: [PATCH net-next] inet: Save one atomic op if no memcg to charge |
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On Mon, Jun 19, 2023 at 10:26 AM Abel Wu <wuyun.abel@bytedance.com> wrote: > > If there is no net-memcg associated with the sock, don't bother > calculating its memory usage for charge. > > Signed-off-by: Abel Wu <wuyun.abel@bytedance.com> > --- > net/ipv4/inet_connection_sock.c | 18 +++++++++++------- > 1 file changed, 11 insertions(+), 7 deletions(-) > > diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c > index 65ad4251f6fd..73798282c1ef 100644 > --- a/net/ipv4/inet_connection_sock.c > +++ b/net/ipv4/inet_connection_sock.c > @@ -706,20 +706,24 @@ struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern) > out: > release_sock(sk); > if (newsk && mem_cgroup_sockets_enabled) { > - int amt; > + int amt = 0; > > /* atomically get the memory usage, set and charge the > * newsk->sk_memcg. > */ > lock_sock(newsk); > > - /* The socket has not been accepted yet, no need to look at > - * newsk->sk_wmem_queued. > - */ > - amt = sk_mem_pages(newsk->sk_forward_alloc + > - atomic_read(&newsk->sk_rmem_alloc)); > mem_cgroup_sk_alloc(newsk); > - if (newsk->sk_memcg && amt) > + if (newsk->sk_memcg) { > + /* The socket has not been accepted yet, no need > + * to look at newsk->sk_wmem_queued. > + */ > + amt = sk_mem_pages(newsk->sk_forward_alloc + > + atomic_read(&newsk->sk_rmem_alloc)); > + > + } > + > + if (amt) > mem_cgroup_charge_skmem(newsk->sk_memcg, amt, > GFP_KERNEL | __GFP_NOFAIL);
This looks correct, but claiming reading an atomic_t is an 'atomic op' is a bit exaggerated.
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