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[34.85.207.234]) by smtp.gmail.com with UTF8SMTPSA id 00721157ae682-7166598b457sm12337247b3.22.2025.07.06.06.53.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 06 Jul 2025 06:53:21 -0700 (PDT) Date: Sun, 06 Jul 2025 09:53:21 -0400 From: Willem de Bruijn To: Kuniyuki Iwashima , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: Simon Horman , Kuniyuki Iwashima , Kuniyuki Iwashima , netdev@vger.kernel.org Message-ID: <686a7fd16830f_3aa6542947b@willemb.c.googlers.com.notmuch> In-Reply-To: <20250702223606.1054680-5-kuniyu@google.com> References: <20250702223606.1054680-1-kuniyu@google.com> <20250702223606.1054680-5-kuniyu@google.com> Subject: Re: [PATCH v1 net-next 4/7] af_unix: Use cached value for SOCK_STREAM in unix_inq_len(). Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Kuniyuki Iwashima wrote: > Compared to TCP, ioctl(SIOCINQ) for AF_UNIX SOCK_STREAM socket is more > expensive, as unix_inq_len() requires iterating through the receive queue > and accumulating skb->len. > > Let's cache the value for SOCK_STREAM to a new field during sendmsg() > and recvmsg(). > > The field is protected by the receive queue lock. nit: for updates, but the read is taken without the lock held, hence the WRITE_ONCE/READ_ONCE accessors. > > Note that ioctl(SIOCINQ) for SOCK_DGRAM returns the length of the first > skb in the queue. > > SOCK_SEQPACKET still requires iterating through the queue because we do > not touch functions shared with unix_dgram_ops. But, if really needed, > we can support it by switching __skb_try_recv_datagram() to a custom > version. > > Signed-off-by: Kuniyuki Iwashima Reviewed-by: Willem de Bruijn