Re: [PATCH v2 19/22] xprtrdma: Support larger inline thresholds

[Anna Schumaker <Anna.Schumaker@netapp.com>]

Hi Chuck,

On 08/23/2016 01:54 PM, Chuck Lever wrote:
> RPC-over-RDMA Version Two will likely require at least a 4KB inline
> threshold by default. The Version One inline threshold is still 1KB,
> and it's automatically negotiated down to in
> rpcrdma_update_connect_private.

I'm curious, what is the status of RPCoRDMA v2?

Thanks,
Anna

> 
> The maximum is somewhat arbitrary. There's no fundamental
> architectural limit I'm aware of, but it's good to keep the size of
> Receive buffers reasonable. Now that Send can use a s/g list, a
> Send buffer is only as large as each RPC requires. Receive buffers
> are always the size of the inline threshold, however.
> 
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
>  include/linux/sunrpc/xprtrdma.h |    4 ++--
>  net/sunrpc/xprtrdma/transport.c |    4 ++--
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/include/linux/sunrpc/xprtrdma.h b/include/linux/sunrpc/xprtrdma.h
> index 39267dc..221b7a2 100644
> --- a/include/linux/sunrpc/xprtrdma.h
> +++ b/include/linux/sunrpc/xprtrdma.h
> @@ -53,8 +53,8 @@
>  #define RPCRDMA_MAX_SLOT_TABLE	(256U)
>  
>  #define RPCRDMA_MIN_INLINE  (1024)	/* min inline thresh */
> -#define RPCRDMA_DEF_INLINE  (1024)	/* default inline thresh */
> -#define RPCRDMA_MAX_INLINE  (3068)	/* max inline thresh */
> +#define RPCRDMA_DEF_INLINE  (4096)	/* default inline thresh */
> +#define RPCRDMA_MAX_INLINE  (65536)	/* max inline thresh */
>  
>  /* Memory registration strategies, by number.
>   * This is part of a kernel / user space API. Do not remove. */
> diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
> index 6a358ab..ed5e285 100644
> --- a/net/sunrpc/xprtrdma/transport.c
> +++ b/net/sunrpc/xprtrdma/transport.c
> @@ -97,7 +97,7 @@ static struct ctl_table xr_tunables_table[] = {
>  		.data		= &xprt_rdma_max_inline_read,
>  		.maxlen		= sizeof(unsigned int),
>  		.mode		= 0644,
> -		.proc_handler	= proc_dointvec,
> +		.proc_handler	= proc_dointvec_minmax,
>  		.extra1		= &min_inline_size,
>  		.extra2		= &max_inline_size,
>  	},
> @@ -106,7 +106,7 @@ static struct ctl_table xr_tunables_table[] = {
>  		.data		= &xprt_rdma_max_inline_write,
>  		.maxlen		= sizeof(unsigned int),
>  		.mode		= 0644,
> -		.proc_handler	= proc_dointvec,
> +		.proc_handler	= proc_dointvec_minmax,
>  		.extra1		= &min_inline_size,
>  		.extra2		= &max_inline_size,
>  	},
> 
> --
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