From: Arjun Roy <arjunroy.kdev@gmail.com>
To: davem@davemloft.net, netdev@vger.kernel.org
Cc: arjunroy@google.com, edumazet@google.com, soheil@google.com
Subject: [net-next v2 5/8] net-zerocopy: Fast return if inq < PAGE_SIZE
Date: Wed, 2 Dec 2020 14:09:42 -0800 [thread overview]
Message-ID: <20201202220945.911116-6-arjunroy.kdev@gmail.com> (raw)
In-Reply-To: <20201202220945.911116-1-arjunroy.kdev@gmail.com>
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 --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);
--
2.29.2.576.ga3fc446d84-goog
next prev parent reply other threads:[~2020-12-02 22:11 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-02 22:09 [net-next v2 0/8] Perf. optimizations for TCP Recv. Zerocopy Arjun Roy
2020-12-02 22:09 ` [net-next v2 1/8] net-zerocopy: Copy straggler unaligned data for TCP Rx. zerocopy Arjun Roy
2020-12-03 0:15 ` Stephen Hemminger
2020-12-03 0:24 ` Arjun Roy
2020-12-03 23:01 ` David Laight
2020-12-03 23:14 ` Eric Dumazet
2020-12-04 9:02 ` David Laight
2020-12-03 23:19 ` Arjun Roy
2020-12-03 23:24 ` Arjun Roy
2020-12-04 9:03 ` David Laight
2020-12-04 22:37 ` Arjun Roy
2020-12-02 22:09 ` [net-next v2 2/8] net-tcp: Introduce tcp_recvmsg_locked() Arjun Roy
2020-12-02 22:09 ` [net-next v2 3/8] net-zerocopy: Refactor skb frag fast-forward op Arjun Roy
2020-12-02 22:09 ` [net-next v2 4/8] net-zerocopy: Refactor frag-is-remappable test Arjun Roy
2020-12-02 22:09 ` Arjun Roy [this message]
2020-12-02 22:09 ` [net-next v2 6/8] net-zerocopy: Introduce short-circuit small reads Arjun Roy
2020-12-02 22:09 ` [net-next v2 7/8] net-zerocopy: Set zerocopy hint when data is copied Arjun Roy
2020-12-02 22:09 ` [net-next v2 8/8] net-zerocopy: Defer vm zap unless actually needed Arjun Roy
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