Re: [RFC 2/2] xprtrdma: remove re_implicit_roundup xprt_rdma_pad_optimize

From: Chuck Lever III <chuck.lever@oracle.com>
To: Olga Kornievskaia <olga.kornievskaia@gmail.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>,
	Anna Schumaker <anna.schumaker@netapp.com>,
	"chuck.level@oracle.com" <chuck.level@oracle.com>,
	Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Subject: Re: [RFC 2/2] xprtrdma: remove re_implicit_roundup xprt_rdma_pad_optimize
Date: Mon, 30 Aug 2021 16:57:25 +0000	[thread overview]
Message-ID: <958545E7-7758-460C-BE3C-451DEA96969B@oracle.com> (raw)
In-Reply-To: <20210830165302.60225-3-olga.kornievskaia@gmail.com>

> On Aug 30, 2021, at 12:53 PM, Olga Kornievskaia <olga.kornievskaia@gmail.com> wrote:
> 
> From: Olga Kornievskaia <kolga@netapp.com>
> 
> Since RPC over RDMA layer no longer needs to manage XDR padding,
> remove existing code that managed whether or not client included
> extra space for the XDR padding.
> 
> Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
> ---
> net/sunrpc/xprtrdma/transport.c | 8 --------
> net/sunrpc/xprtrdma/verbs.c     | 2 --
> net/sunrpc/xprtrdma/xprt_rdma.h | 6 ------
> 3 files changed, 16 deletions(-)
> 
> diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
> index 16e5696314a4..e7b9d88f4483 100644
> --- a/net/sunrpc/xprtrdma/transport.c
> +++ b/net/sunrpc/xprtrdma/transport.c
> @@ -72,7 +72,6 @@ static unsigned int xprt_rdma_slot_table_entries = RPCRDMA_DEF_SLOT_TABLE;
> unsigned int xprt_rdma_max_inline_read = RPCRDMA_DEF_INLINE;
> unsigned int xprt_rdma_max_inline_write = RPCRDMA_DEF_INLINE;
> unsigned int xprt_rdma_memreg_strategy		= RPCRDMA_FRWR;
> -int xprt_rdma_pad_optimize;
> static struct xprt_class xprt_rdma;
> 
> #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
> @@ -134,13 +133,6 @@ static struct ctl_table xr_tunables_table[] = {
> 		.extra1		= &min_memreg,
> 		.extra2		= &max_memreg,
> 	},
> -	{
> -		.procname	= "rdma_pad_optimize",
> -		.data		= &xprt_rdma_pad_optimize,
> -		.maxlen		= sizeof(unsigned int),
> -		.mode		= 0644,
> -		.proc_handler	= proc_dointvec,
> -	},
> 	{ },
> };

I have to NACK at least this hunk: my understanding is we
can't just remove /proc interfaces.

> diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
> index aaec3c9be8db..d8650a3563ef 100644
> --- a/net/sunrpc/xprtrdma/verbs.c
> +++ b/net/sunrpc/xprtrdma/verbs.c
> @@ -205,14 +205,12 @@ static void rpcrdma_update_cm_private(struct rpcrdma_ep *ep,
> 	unsigned int rsize, wsize;
> 
> 	/* Default settings for RPC-over-RDMA Version One */
> -	ep->re_implicit_roundup = xprt_rdma_pad_optimize;
> 	rsize = RPCRDMA_V1_DEF_INLINE_SIZE;
> 	wsize = RPCRDMA_V1_DEF_INLINE_SIZE;
> 
> 	if (pmsg &&
> 	    pmsg->cp_magic == rpcrdma_cmp_magic &&
> 	    pmsg->cp_version == RPCRDMA_CMP_VERSION) {
> -		ep->re_implicit_roundup = true;
> 		rsize = rpcrdma_decode_buffer_size(pmsg->cp_send_size);
> 		wsize = rpcrdma_decode_buffer_size(pmsg->cp_recv_size);
> 	}
> diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
> index d91f54eae00b..137866a83a3a 100644
> --- a/net/sunrpc/xprtrdma/xprt_rdma.h
> +++ b/net/sunrpc/xprtrdma/xprt_rdma.h
> @@ -74,7 +74,6 @@ struct rpcrdma_ep {
> 	struct ib_pd		*re_pd;
> 	unsigned int		re_max_rdma_segs;
> 	unsigned int		re_max_fr_depth;
> -	bool			re_implicit_roundup;
> 	enum ib_mr_type		re_mrtype;
> 	struct completion	re_done;
> 	unsigned int		re_send_count;
> @@ -441,11 +440,6 @@ rpcrdma_portstr(const struct rpcrdma_xprt *r_xprt)
> 	return r_xprt->rx_xprt.address_strings[RPC_DISPLAY_PORT];
> }
> 
> -/* Setting this to 0 ensures interoperability with early servers.
> - * Setting this to 1 enhances certain unaligned read/write performance.
> - * Default is 0, see sysctl entry and rpc_rdma.c rpcrdma_convert_iovs() */
> -extern int xprt_rdma_pad_optimize;
> -
> /* This setting controls the hunt for a supported memory
>  * registration strategy.
>  */
> -- 
> 2.27.0
> 

--
Chuck Lever