Return-Path: Received: from mx142.netapp.com ([216.240.21.19]:3070 "EHLO mx142.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2993233AbbEEOoV (ORCPT ); Tue, 5 May 2015 10:44:21 -0400 Message-ID: <5548D741.7090803@Netapp.com> Date: Tue, 5 May 2015 10:44:17 -0400 From: Anna Schumaker MIME-Version: 1.0 To: Chuck Lever CC: , Linux NFS Mailing List Subject: Re: [PATCH v1 01/14] xprtrdma: Transport fault injection References: <20150504174626.3483.97639.stgit@manet.1015granger.net> <20150504175651.3483.35554.stgit@manet.1015granger.net> <5548CA82.9060903@Netapp.com> <06C797AA-4E45-49DA-8CA8-2B8D22B818DB@oracle.com> In-Reply-To: <06C797AA-4E45-49DA-8CA8-2B8D22B818DB@oracle.com> Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: On 05/05/2015 09:53 AM, Chuck Lever wrote: > > On May 5, 2015, at 9:49 AM, Anna Schumaker wrote: > >> Hi Chuck, >> >> Neat idea! Are servers able to handle client recovery without getting too confused? > > So far I have encountered only issues on the client side. I think this > is because the client is the active part of re-establishing transport > connections. In addition, RPC/RDMA clients have a bunch of resources > that need to be reset after a transport disconnect. > > I think this idea can be translated into something that can be done > in the generic layer (ie, xprt.c) if people think that would be of > benefit for testing TCP also. It might, and now is the time to discuss it before we're stuck maintaining multiple interfaces to the same thing. Another thought: can you move this under debugfs instead of proc? That's where the other kernel fault injection controls are, and it might give us a little more flexibility if we need to change the interface later. Anna > > >> Anna >> >> On 05/04/2015 01:56 PM, Chuck Lever wrote: >>> It has been exceptionally useful to exercise the logic that handles >>> local immediate errors and RDMA connection loss. To enable >>> developers to test this regularly and repeatably, add logic to >>> simulate connection loss every so often. >>> >>> Fault injection is disabled by default. It is enabled with >>> >>> $ sudo echo xxx > /proc/sys/sunrpc/rdma_inject_transport_fault >>> >>> where "xxx" is a large positive number of transport method calls >>> before a disconnect. A value of several thousand is usually a good >>> number that allows reasonable forward progress while still causing a >>> lot of connection drops. >>> >>> Signed-off-by: Chuck Lever >>> --- >>> net/sunrpc/Kconfig | 12 ++++++++++++ >>> net/sunrpc/xprtrdma/transport.c | 34 ++++++++++++++++++++++++++++++++++ >>> net/sunrpc/xprtrdma/xprt_rdma.h | 1 + >>> 3 files changed, 47 insertions(+) >>> >>> diff --git a/net/sunrpc/Kconfig b/net/sunrpc/Kconfig >>> index 9068e72..329f82c 100644 >>> --- a/net/sunrpc/Kconfig >>> +++ b/net/sunrpc/Kconfig >>> @@ -61,6 +61,18 @@ config SUNRPC_XPRT_RDMA_CLIENT >>> >>> If unsure, say N. >>> >>> +config SUNRPC_XPRT_RDMA_FAULT_INJECTION >>> + bool "RPC over RDMA client fault injection" >>> + depends on SUNRPC_XPRT_RDMA_CLIENT >>> + default N >>> + help >>> + This option enables fault injection in the xprtrdma module. >>> + Fault injection is disabled by default. It is enabled with: >>> + >>> + $ sudo echo xxx > /proc/sys/sunrpc/rdma_inject_fault >>> + >>> + If unsure, say N. >>> + >>> config SUNRPC_XPRT_RDMA_SERVER >>> tristate "RPC over RDMA Server Support" >>> depends on SUNRPC && INFINIBAND && INFINIBAND_ADDR_TRANS >>> diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c >>> index 54f23b1..fdcb2c7 100644 >>> --- a/net/sunrpc/xprtrdma/transport.c >>> +++ b/net/sunrpc/xprtrdma/transport.c >>> @@ -74,6 +74,7 @@ static unsigned int xprt_rdma_max_inline_write = RPCRDMA_DEF_INLINE; >>> static unsigned int xprt_rdma_inline_write_padding; >>> static unsigned int xprt_rdma_memreg_strategy = RPCRDMA_FRMR; >>> int xprt_rdma_pad_optimize = 1; >>> +static unsigned int xprt_rdma_inject_transport_fault; >>> >>> #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) >>> >>> @@ -135,6 +136,13 @@ static struct ctl_table xr_tunables_table[] = { >>> .mode = 0644, >>> .proc_handler = proc_dointvec, >>> }, >>> + { >>> + .procname = "rdma_inject_transport_fault", >>> + .data = &xprt_rdma_inject_transport_fault, >>> + .maxlen = sizeof(unsigned int), >>> + .mode = 0644, >>> + .proc_handler = proc_dointvec, >>> + }, >>> { }, >>> }; >>> >>> @@ -246,6 +254,27 @@ xprt_rdma_connect_worker(struct work_struct *work) >>> xprt_clear_connecting(xprt); >>> } >>> >>> +#if defined CONFIG_SUNRPC_XPRT_RDMA_FAULT_INJECTION >>> +static void >>> +xprt_rdma_inject_disconnect(struct rpcrdma_xprt *r_xprt) >>> +{ >>> + if (!xprt_rdma_inject_transport_fault) >>> + return; >>> + >>> + if (atomic_dec_return(&r_xprt->rx_inject_count) == 0) { >>> + atomic_set(&r_xprt->rx_inject_count, >>> + xprt_rdma_inject_transport_fault); >>> + pr_info("rpcrdma: injecting transport disconnect\n"); >>> + (void)rdma_disconnect(r_xprt->rx_ia.ri_id); >>> + } >>> +} >>> +#else >>> +static void >>> +xprt_rdma_inject_disconnect(struct rpcrdma_xprt *r_xprt) >>> +{ >>> +} >>> +#endif >>> + >>> /* >>> * xprt_rdma_destroy >>> * >>> @@ -405,6 +434,8 @@ xprt_setup_rdma(struct xprt_create *args) >>> INIT_DELAYED_WORK(&new_xprt->rx_connect_worker, >>> xprt_rdma_connect_worker); >>> >>> + atomic_set(&new_xprt->rx_inject_count, >>> + xprt_rdma_inject_transport_fault); >>> xprt_rdma_format_addresses(xprt); >>> xprt->max_payload = new_xprt->rx_ia.ri_ops->ro_maxpages(new_xprt); >>> if (xprt->max_payload == 0) >>> @@ -515,6 +546,7 @@ xprt_rdma_allocate(struct rpc_task *task, size_t size) >>> out: >>> dprintk("RPC: %s: size %zd, request 0x%p\n", __func__, size, req); >>> req->rl_connect_cookie = 0; /* our reserved value */ >>> + xprt_rdma_inject_disconnect(r_xprt); >>> return req->rl_sendbuf->rg_base; >>> >>> out_rdmabuf: >>> @@ -589,6 +621,7 @@ xprt_rdma_free(void *buffer) >>> } >>> >>> rpcrdma_buffer_put(req); >>> + xprt_rdma_inject_disconnect(r_xprt); >>> } >>> >>> /* >>> @@ -634,6 +667,7 @@ xprt_rdma_send_request(struct rpc_task *task) >>> >>> rqst->rq_xmit_bytes_sent += rqst->rq_snd_buf.len; >>> rqst->rq_bytes_sent = 0; >>> + xprt_rdma_inject_disconnect(r_xprt); >>> return 0; >>> >>> failed_marshal: >>> diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h >>> index 78e0b8b..08aee53 100644 >>> --- a/net/sunrpc/xprtrdma/xprt_rdma.h >>> +++ b/net/sunrpc/xprtrdma/xprt_rdma.h >>> @@ -377,6 +377,7 @@ struct rpcrdma_xprt { >>> struct rpcrdma_create_data_internal rx_data; >>> struct delayed_work rx_connect_worker; >>> struct rpcrdma_stats rx_stats; >>> + atomic_t rx_inject_count; >>> }; >>> >>> #define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, rx_xprt) >>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in >>> the body of a message to majordomo@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>> >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-rdma" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- > Chuck Lever > chuck[dot]lever[at]oracle[dot]com > > >