From owner-svn-src-stable@freebsd.org Wed Jun 15 09:39:42 2016 Return-Path: Delivered-To: svn-src-stable@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id D3712A1D1CA; Wed, 15 Jun 2016 09:39:42 +0000 (UTC) (envelope-from sephe@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id AB1ED1DEA; Wed, 15 Jun 2016 09:39:42 +0000 (UTC) (envelope-from sephe@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id u5F9df2j093517; Wed, 15 Jun 2016 09:39:41 GMT (envelope-from sephe@FreeBSD.org) Received: (from sephe@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id u5F9dffE093515; Wed, 15 Jun 2016 09:39:41 GMT (envelope-from sephe@FreeBSD.org) Message-Id: <201606150939.u5F9dffE093515@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: sephe set sender to sephe@FreeBSD.org using -f From: Sepherosa Ziehau Date: Wed, 15 Jun 2016 09:39:41 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r301924 - stable/10/sys/dev/hyperv/vmbus X-SVN-Group: stable-10 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-stable@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: SVN commit messages for all the -stable branches of the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 15 Jun 2016 09:39:42 -0000 Author: sephe Date: Wed Jun 15 09:39:41 2016 New Revision: 301924 URL: https://svnweb.freebsd.org/changeset/base/301924 Log: MFC 297219 hyperv/vmbus: use a better retry method in hv_vmbus_post_message() Most often, hv_vmbus_post_message() doesn't fail. However, it fails intermittently when GPADLs of large shared memory is to be established with the host, e.g. on the hn(4) attach path: a GPADL of 15MB sendbuf is created, for which lots of messages will be flooded to the host. The host side tries to throttle the message rate by returning HV_STATUS_INSUFFICIENT_BUFFERS. Before this commit, we do several retries for failed messages, but the delay between each retry is pretty/too low, which will cause sporadic message posting failure. We now use large delay (>=1ms) between each retry to fix the message posting failure. Submitted by: Dexuan Cui Reviewed by: sephe MFC after: 1 week Sponsored by: Microsoft OSTC Differential Revision: https://reviews.freebsd.org/D5715 Modified: stable/10/sys/dev/hyperv/vmbus/hv_connection.c stable/10/sys/dev/hyperv/vmbus/hv_vmbus_priv.h Directory Properties: stable/10/ (props changed) Modified: stable/10/sys/dev/hyperv/vmbus/hv_connection.c ============================================================================== --- stable/10/sys/dev/hyperv/vmbus/hv_connection.c Wed Jun 15 09:08:14 2016 (r301923) +++ stable/10/sys/dev/hyperv/vmbus/hv_connection.c Wed Jun 15 09:39:41 2016 (r301924) @@ -367,31 +367,35 @@ hv_vmbus_on_events(int cpu) /** * Send a msg on the vmbus's message connection */ -int hv_vmbus_post_message(void *buffer, size_t bufferLen) { - int ret = 0; +int hv_vmbus_post_message(void *buffer, size_t bufferLen) +{ hv_vmbus_connection_id connId; - unsigned retries = 0; - - /* NetScaler delays from previous code were consolidated here */ - static int delayAmount[] = {100, 100, 100, 500, 500, 5000, 5000, 5000}; - - /* for(each entry in delayAmount) try to post message, - * delay a little bit before retrying + sbintime_t time = SBT_1MS; + int retries; + int ret; + + connId.as_uint32_t = 0; + connId.u.id = HV_VMBUS_MESSAGE_CONNECTION_ID; + + /* + * We retry to cope with transient failures caused by host side's + * insufficient resources. 20 times should suffice in practice. */ - for (retries = 0; - retries < sizeof(delayAmount)/sizeof(delayAmount[0]); retries++) { - connId.as_uint32_t = 0; - connId.u.id = HV_VMBUS_MESSAGE_CONNECTION_ID; - ret = hv_vmbus_post_msg_via_msg_ipc(connId, 1, buffer, bufferLen); - if (ret != HV_STATUS_INSUFFICIENT_BUFFERS) - break; - /* TODO: KYS We should use a blocking wait call */ - DELAY(delayAmount[retries]); + for (retries = 0; retries < 20; retries++) { + ret = hv_vmbus_post_msg_via_msg_ipc(connId, 1, buffer, + bufferLen); + if (ret == HV_STATUS_SUCCESS) + return (0); + + pause_sbt("pstmsg", time, 0, C_HARDCLOCK); + if (time < SBT_1S * 2) + time *= 2; } - KASSERT(ret == 0, ("Error VMBUS: Message Post Failed\n")); + KASSERT(ret == HV_STATUS_SUCCESS, + ("Error VMBUS: Message Post Failed, ret=%d\n", ret)); - return (ret); + return (EAGAIN); } /** Modified: stable/10/sys/dev/hyperv/vmbus/hv_vmbus_priv.h ============================================================================== --- stable/10/sys/dev/hyperv/vmbus/hv_vmbus_priv.h Wed Jun 15 09:08:14 2016 (r301923) +++ stable/10/sys/dev/hyperv/vmbus/hv_vmbus_priv.h Wed Jun 15 09:39:41 2016 (r301924) @@ -70,6 +70,7 @@ typedef uint16_t hv_vmbus_status; * You did not supply enough message buffers to send a message. */ +#define HV_STATUS_SUCCESS ((uint16_t)0) #define HV_STATUS_INSUFFICIENT_BUFFERS ((uint16_t)0x0013) typedef void (*hv_vmbus_channel_callback)(void *context);