From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7136C377541 for ; Fri, 28 Aug 2026 18:19:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787941192; cv=none; b=d7GhkuA42PbM9xcuKpcrJgiVWJwo8vZOsbk5AY8LlopXDdlHMbu4z3t0XEH0zSHpxEKGlTWsPLIdkf0TrJajJrVImRMuQXQ3hn83YF3OWnoXm1nrAypnebpv0pdVlN9N80WA4nu/KFsL+DZZQ/AF85a9YwiMlZjf4BTaLGLJGPc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787941192; c=relaxed/simple; bh=loKORHkreUY6wk+H8VgjcnoyJpQTXFmsW3s4iSpTMFk=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=ggF3W/Nfp5Ch5H+hzfPRMb5zhmkg86u9eZFxHn/XELqC0CvW2R1lqsxLn3rJTh+TOTrJyT3hbRslcx+yhRyhzf/ZLSbdYVbxin9Juc0LEJjYUYp8hix/pYmfOG4Y7ABrCMzB9hQ3KjUJ3MZZiWwzUWtWzr8EqARfTVchaYxeqRM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=L3g1T8qe; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="L3g1T8qe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B46D81F000E9; Fri, 28 Aug 2026 18:19:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787941191; bh=O17pZ8jeA+x3xKlk9in/e5UUXdVuWRGfdVgdBtiRWGg=; h=Subject:From:To:Cc:Date:In-Reply-To:References; b=L3g1T8qeZEE8pHT9GnvjlUjDNZc3Q2bCtbwVSkpW79QajWSMo7W1QlSGESo96Gvsi PtFQ8gPPIGBXKZIqE0uOrFdzeWFmFHu1st4tBVv92oWdyXQgoFYyFisOhlh0Nl9GPH jtGiH+qv/BfRStXG3XogqtL8H2Sq9UZ6LqK0N4izQW0t1qPnGJ3aoNPgu4+lslIBEH u77wIXCXqrKvk4d4lW9F/i8uyCsvHy34ZYVWlvph4OGuvPw9U30QHcvgONu9guffrE hm+xPfYzQ3ssHDq+rmRqMRJHwNQo+qgNtjRKQHVOc55AyA57Lv4FPKvYMKsmY03xvD D9SdtjuAsiVSw== Message-ID: <798a28cffecc0c16e30841f8a5edaba2a718986b.camel@kernel.org> Subject: Re: [PATCH v2 4/7] SUNRPC: Mark connection-oriented transports on svc_xprt From: Jeff Layton To: Chuck Lever , NeilBrown , Olga Kornievskaia , Dai Ngo , Tom Talpey Cc: Rick Macklem , linux-nfs@vger.kernel.org Date: Fri, 28 Aug 2026 14:19:48 -0400 In-Reply-To: <20260828-duplicate-reply-cache-v2-4-25069e660a7b@kernel.org> References: <20260828-duplicate-reply-cache-v2-0-25069e660a7b@kernel.org> <20260828-duplicate-reply-cache-v2-4-25069e660a7b@kernel.org> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV 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Fri, 2026-08-28 at 12:17 -0400, Chuck Lever wrote: > A TCP or RDMA svc_xprt carries one client's request stream, delivered > reliably and in order, so a later request on it indicates that earlier > replies reached the client. A UDP svc_xprt is shared by every peer and > offers no such signal. >=20 > Add an XPT_ORDERED flag, set by the TCP and RDMA init paths and clear > for UDP, so the NFSD duplicate reply cache can confine implied-ACK > eviction to transports where the signal holds. >=20 > The flag has a cost on svcrdma. handle_connect_req() zeroes the remote > port in the DRC key so a cached reply survives a reconnect, and > implied-ACK eviction can retire such an entry while the original > connection is still up. TCP gives up the same thing whenever a client > re-binds its reserved port, so this follows from the eviction policy > rather than from RDMA. >=20 > Signed-off-by: Chuck Lever > --- > include/linux/sunrpc/svc_xprt.h | 1 + > include/trace/events/sunrpc.h | 1 + > net/sunrpc/svcsock.c | 1 + > net/sunrpc/xprtrdma/svc_rdma_transport.c | 1 + > 4 files changed, 4 insertions(+) >=20 > diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_x= prt.h > index 53ed073640a6..ebab18e403b2 100644 > --- a/include/linux/sunrpc/svc_xprt.h > +++ b/include/linux/sunrpc/svc_xprt.h > @@ -99,6 +99,7 @@ enum { > XPT_LOCAL, /* connection from loopback interface */ > XPT_KILL_TEMP, /* call xpo_kill_temp_xprt before closing */ > XPT_CONG_CTRL, /* has congestion control */ > + XPT_ORDERED, /* connection-oriented, in-order delivery */ > XPT_HANDSHAKE, /* xprt requests a handshake */ > XPT_TLS_SESSION, /* transport-layer security established */ > XPT_PEER_AUTH, /* peer has been authenticated */ > diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.= h > index 180346e520ff..2154fbe69945 100644 > --- a/include/trace/events/sunrpc.h > +++ b/include/trace/events/sunrpc.h > @@ -1931,6 +1931,7 @@ TRACE_EVENT(svc_stats_latency, > svc_xprt_flag(LOCAL) \ > svc_xprt_flag(KILL_TEMP) \ > svc_xprt_flag(CONG_CTRL) \ > + svc_xprt_flag(ORDERED) \ > svc_xprt_flag(HANDSHAKE) \ > svc_xprt_flag(TLS_SESSION) \ > svc_xprt_flag(PEER_AUTH) \ > diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c > index 840bec53e1ee..97a592ddeb48 100644 > --- a/net/sunrpc/svcsock.c > +++ b/net/sunrpc/svcsock.c > @@ -1486,6 +1486,7 @@ static bool svc_tcp_init(struct svc_sock *svsk, str= uct svc_serv *serv) > return false; > set_bit(XPT_CACHE_AUTH, &svsk->sk_xprt.xpt_flags); > set_bit(XPT_CONG_CTRL, &svsk->sk_xprt.xpt_flags); > + set_bit(XPT_ORDERED, &svsk->sk_xprt.xpt_flags); > if (sk->sk_state =3D=3D TCP_LISTEN) { > strcpy(svsk->sk_xprt.xpt_remotebuf, "listener"); > set_bit(XPT_LISTENER, &svsk->sk_xprt.xpt_flags); > diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrd= ma/svc_rdma_transport.c > index fabdfd891a41..5d39fce231a3 100644 > --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c > +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c > @@ -218,6 +218,7 @@ static struct svcxprt_rdma *svc_rdma_create_xprt(stru= ct svc_serv *serv, > * transports are suitable here. > */ > set_bit(XPT_CONG_CTRL, &cma_xprt->sc_xprt.xpt_flags); > + set_bit(XPT_ORDERED, &cma_xprt->sc_xprt.xpt_flags); > =20 > return cma_xprt; > } It would be helpful to see how this new flag will be used other than in the tracepoint. Maybe this patch should be folded into the following one? --=20 Jeff Layton