Re: [PATCH v3 0/2] NFSD: delay unmount source's export after inter-server copy completed.

[Chuck Lever III <chuck.lever@oracle.com>]

> On Apr 9, 2021, at 2:05 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
> 
> Hi Olga,
> 
> Currently the source's export is mounted and unmounted on every
> inter-server copy operation. This causes unnecessary overhead
> for each copy.
> 
> This patch series is an enhancement to allow the export to remain
> mounted for a configurable period (default to 15 minutes). If the 
> export is not being used for the configured time it will be unmounted
> by a delayed task. If it's used again then its expiration time is
> extended for another period.
> 
> Since mount and unmount are no longer done on each copy request,
> this overhead is no longer used to decide whether the copy should
> be done with inter-server copy or generic copy. The threshold is
> now a module configuration parameter, default to 16MB.
> 
> -Dai
> 
> v2: fix compiler warning of missing prototype.
> v3: remove the used of semaphore.
>    eliminated all RPC calls for subsequence mount by allowing
>       all exports from one server to share one vfsmount.
>    make inter-server threshold a module configuration parameter.

This series is close, but it doesn't seem 100% ready yet. Let's
defer it for the next merge window to give a little more time for
review, testing, and discussion.


--
Chuck Lever