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From:   Chuck Lever III <chuck.lever@oracle.com>
To:     Dai Ngo <dai.ngo@oracle.com>,
        Olga Kornievskaia <olga.kornievskaia@gmail.com>
CC:     Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
        Trond Myklebust <trondmy@hammerspace.com>,
        Bruce Fields <bfields@fieldses.org>
Subject: Re: [PATCH v3 0/2] NFSD: delay unmount source's export after
 inter-server copy completed.
Thread-Topic: [PATCH v3 0/2] NFSD: delay unmount source's export after
 inter-server copy completed.
Thread-Index: AQHXLWs+IUqPLQz5x0aAPxNFKIe5u6qvibcA
Date:   Sun, 11 Apr 2021 16:46:55 +0000
Message-ID: <5E7177EB-DE0D-434C-89DF-5BC090FBE642@oracle.com>
References: <20210409180519.25405-1-dai.ngo@oracle.com>
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> On Apr 9, 2021, at 2:05 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>=20
> Hi Olga,
>=20
> Currently the source's export is mounted and unmounted on every
> inter-server copy operation. This causes unnecessary overhead
> for each copy.
>=20
> This patch series is an enhancement to allow the export to remain
> mounted for a configurable period (default to 15 minutes). If the=20
> 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.
>=20
> 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.
>=20
> -Dai
>=20
> 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