Re: [PATCH v1 01/14] xprtrdma: Transport fault injection

Anna Schumaker
2015-05-05T13:49:54Z

Hi Chuck,

Neat idea! Are servers able to handle client recovery without getting too confused?

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 <chuck.lever-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
> ---
> 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)
>
> --
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