Re: [PATCH v2 1/1] NFSD: send OP_CB_RECALL_ANY to clients when number of delegations reaches its limit

[Dai Ngo <dai.ngo@oracle.com>]

On 3/5/24 12:49 AM, Cedric Blancher wrote:
> On Sun, 3 Mar 2024 at 23:23, Dai Ngo <dai.ngo@oracle.com> wrote:
>> The NFS server should ask clients to voluntarily return unused
>> delegations when the number of granted delegations reaches the
>> max_delegations. This is so that the server can continue to
>> grant delegations for new requests.
> What is this limit max_delegations?

4 delegations per megabyte of available RAM.

>   Where is it set,

when nfsd starts up.

>   and where can an
> admin alter it at runtime?

There is no admin tool to change this setting. But if you want to
play with it then you can poke the memory and change its value,
The code uses max_delegations dynamically.

-Dai

>
> Are you aware that for example the msnfs41client Windows NFSv4.1
> driver easily uses a few hundred delegations, as required by the
> highly multithreaded nature (i.e. every Win32 syscall is async) of the
> Windows kernel?
>
> Ced