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Miller" , David Ahern , Jakub Kicinski , Paolo Abeni , "open list:NETWORKING [IPv4/IPv6]" , open list References: <20230619082547.73929-1-wuyun.abel@bytedance.com> From: Abel Wu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/19/23 6:08 PM, Eric Dumazet wrote: > On Mon, Jun 19, 2023 at 10:26 AM Abel Wu 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 >> --- >> 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. Yeah, shall I change subject to 'inet: Skip usage calculation if no memcg to charge'? Or do you have any suggestions? Thanks, Abel