user/sven/linux.git/include/uapi/linux/tcp.h, branch v5.14.9

tcp: Sanitize CMSG flags and reserved args in tcp_zerocopy_receive.

2021-02-12T02:25:05Z

Explicitly define reserved field and require it and any subsequent fields to be zero-valued for now. Additionally, limit the valid CMSG flags that tcp_zerocopy_receive accepts. Fixes: 7eeba1706eba ("tcp: Add receive timestamp support for receive zerocopy.") Signed-off-by: Arjun Roy Signed-off-by: Eric Dumazet Signed-off-by: Soheil Hassas Yeganeh Suggested-by: David Ahern Suggested-by: Leon Romanovsky Suggested-by: Jakub Kicinski Acked-by: Jakub Kicinski Signed-off-by: David S. Miller

tcp: Add receive timestamp support for receive zerocopy.

2021-01-23T04:05:56Z

tcp_recvmsg() uses the CMSG mechanism to receive control information like packet receive timestamps. This patch adds CMSG fields to struct tcp_zerocopy_receive, and provides receive timestamps if available to the user. Signed-off-by: Arjun Roy Signed-off-by: Jakub Kicinski

tcp: add TTL to SCM_TIMESTAMPING_OPT_STATS

2021-01-23T02:20:52Z

This patch adds TCP_NLA_TTL to SCM_TIMESTAMPING_OPT_STATS that exports the time-to-live or hop limit of the latest incoming packet with SCM_TSTAMP_ACK. The value exported may not be from the packet that acks the sequence when incoming packets are aggregated. Exporting the time-to-live or hop limit value of incoming packets helps to estimate the hop count of the path of the flow that may change over time. Signed-off-by: Yousuk Seung Signed-off-by: Eric Dumazet Signed-off-by: Neal Cardwell Link: https://lore.kernel.org/r/20210120204155.552275-1-ysseung@google.com Signed-off-by: Jakub Kicinski

Fix whitespace in uapi/linux/tcp.h.

2021-01-12T01:23:26Z

List of things fixed: - Two of the socket options were idented with spaces instead of tabs. - Trailing whitespace in some lines. - Improper spacing around parenthesis caught by checkpatch.pl. - Mix of space and tabs in tcp_word_hdr union. Signed-off-by: Danilo Carvalho Link: https://lore.kernel.org/r/20210108222104.2079472-1-doak@google.com Signed-off-by: Jakub Kicinski

net-zerocopy: Defer vm zap unless actually needed.

2020-12-04T21:40:53Z

Zapping pages is required only if we are calling vm_insert_page into a region where pages had previously been mapped. Receive zerocopy allows reusing such regions, and hitherto called zap_page_range() before calling vm_insert_page() in that range. zap_page_range() can also be triggered from userspace with madvise(MADV_DONTNEED). If userspace is configured to call this before reusing a segment, or if there was nothing mapped at this virtual address to begin with, we can avoid calling zap_page_range() under the socket lock. That said, if userspace does not do that, then we are still responsible for calling zap_page_range(). This patch adds a flag that the user can use to hint to the kernel that a zap is not required. If the flag is not set, or if an older user application does not have a flags field at all, then the kernel calls zap_page_range as before. Also, if the flag is set but a zap is still required, the kernel performs that zap as necessary. Thus incorrectly indicating that a zap can be avoided does not change the correctness of operation. It also increases the batchsize for vm_insert_pages and prefetches the page struct for the batch since we're about to bump the refcount. An alternative mechanism could be to not have a flag, assume by default a zap is not needed, and fall back to zapping if needed. However, this would harm performance for older applications for which a zap is necessary, and thus we implement it with an explicit flag so newer applications can opt in. When using RPC-style traffic with medium sized (tens of KB) RPCs, this change yields an efficency improvement of about 30% for QPS/CPU usage. Signed-off-by: Arjun Roy Signed-off-by: Eric Dumazet Signed-off-by: Soheil Hassas Yeganeh Signed-off-by: Jakub Kicinski

net-zerocopy: Copy straggler unaligned data for TCP Rx. zerocopy.

2020-12-04T21:40:52Z

When TCP receive zerocopy does not successfully map the entire requested space, it outputs a 'hint' that the caller should recvmsg(). Augment zerocopy to accept a user buffer that it tries to copy this hint into - if it is possible to copy the entire hint, it will do so. This elides a recvmsg() call for received traffic that isn't exactly page-aligned in size. This was tested with RPC-style traffic of arbitrary sizes. Normally, each received message required at least one getsockopt() call, and one recvmsg() call for the remaining unaligned data. With this change, almost all of the recvmsg() calls are eliminated, leading to a savings of about 25%-50% in number of system calls for RPC-style workloads. Signed-off-by: Arjun Roy Signed-off-by: Eric Dumazet Signed-off-by: Soheil Hassas Yeganeh Signed-off-by: Jakub Kicinski

tcp: add earliest departure time to SCM_TIMESTAMPING_OPT_STATS

2020-08-01T00:00:44Z

This change adds TCP_NLA_EDT to SCM_TIMESTAMPING_OPT_STATS that reports the earliest departure time(EDT) of the timestamped skb. By tracking EDT values of the skb from different timestamps, we can observe when and how much the value changed. This allows to measure the precise delay injected on the sender host e.g. by a bpf-base throttler. Signed-off-by: Yousuk Seung Signed-off-by: Eric Dumazet Acked-by: Neal Cardwell Acked-by: Soheil Hassas Yeganeh Acked-by: Yuchung Cheng Signed-off-by: David S. Miller

tcp: add bytes not sent to SCM_TIMESTAMPING_OPT_STATS

2020-03-10T00:56:33Z

Add TCP_NLA_BYTES_NOTSENT to SCM_TIMESTAMPING_OPT_STATS that reports bytes in the write queue but not sent. This is the same metric as what is exported with tcp_info.tcpi_notsent_bytes. Signed-off-by: Yousuk Seung Signed-off-by: Eric Dumazet Acked-by: Soheil Hassas Yeganeh Acked-by: Yuchung Cheng Acked-by: Neal Cardwell Signed-off-by: David S. Miller

tcp-zerocopy: Return sk_err (if set) along with tcp receive zerocopy.

2020-02-17T03:25:02Z

This patchset is intended to reduce the number of extra system calls imposed by TCP receive zerocopy. For ping-pong RPC style workloads, this patchset has demonstrated a system call reduction of about 30% when coupled with userspace changes. For applications using epoll, returning sk_err along with the result of tcp receive zerocopy could remove the need to call recvmsg()=-EAGAIN after a spurious wakeup. Consider a multi-threaded application using epoll. A thread may awaken with EPOLLIN but another thread may already be reading. The spuriously-awoken thread does not necessarily know that another thread 'won'; rather, it may be possible that it was woken up due to the presence of an error if there is no data. A zerocopy read receiving 0 bytes thus would need to be followed up by recvmsg to be sure. Instead, we return sk_err directly with zerocopy, so the application can avoid this extra system call. Signed-off-by: Arjun Roy Signed-off-by: Eric Dumazet Signed-off-by: Soheil Hassas Yeganeh Signed-off-by: David S. Miller

tcp-zerocopy: Return inq along with tcp receive zerocopy.

2020-02-17T03:25:02Z

This patchset is intended to reduce the number of extra system calls imposed by TCP receive zerocopy. For ping-pong RPC style workloads, this patchset has demonstrated a system call reduction of about 30% when coupled with userspace changes. For applications using edge-triggered epoll, returning inq along with the result of tcp receive zerocopy could remove the need to call recvmsg()=-EAGAIN after a successful zerocopy. Generally speaking, since normally we would need to perform a recvmsg() call for every successful small RPC read via TCP receive zerocopy, returning inq can reduce the number of system calls performed by approximately half. Signed-off-by: Arjun Roy Signed-off-by: Eric Dumazet Signed-off-by: Soheil Hassas Yeganeh Signed-off-by: David S. Miller