diff mbox series

[net-next,v2,5/8] net-zerocopy: Fast return if inq < PAGE_SIZE

Message ID 20201202220945.911116-6-arjunroy.kdev@gmail.com
State New
Headers show
Series Perf. optimizations for TCP Recv. Zerocopy | expand

Commit Message

Arjun Roy Dec. 2, 2020, 10:09 p.m. UTC 
From: Arjun Roy <arjunroy@google.com>

Sometimes, we may call tcp receive zerocopy when inq is 0,
or inq < PAGE_SIZE, in which case we cannot remap pages. In this case,
simply return the appropriate hint for regular copying without taking
mmap_sem.
---
 net/ipv4/tcp.c | 8 ++++++++
 1 file changed, 8 insertions(+)
diff mbox series

Patch

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 4bdd4a358588..b2f24a5ec230 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1889,6 +1889,14 @@  static int tcp_zerocopy_receive(struct sock *sk,
 
 	sock_rps_record_flow(sk);
 
+	if (inq < PAGE_SIZE) {
+		zc->length = 0;
+		zc->recv_skip_hint = inq;
+		if (!inq && sock_flag(sk, SOCK_DONE))
+			return -EIO;
+		return 0;
+	}
+
 	mmap_read_lock(current->mm);
 
 	vma = find_vma(current->mm, address);