From: Trond Myklebust <trondmy@hammerspace.com>
To: "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
"richard@nod.at" <richard@nod.at>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"anna.schumaker@netapp.com" <anna.schumaker@netapp.com>,
"david@sigma-star.at" <david@sigma-star.at>
Subject: Re: [RFC PATCH] NFS: Save 4 bytes when re-exporting
Date: Sun, 12 Dec 2021 21:19:59 +0000 [thread overview]
Message-ID: <dd3aec8fed9bab9b3e62fc2093803688b7b71682.camel@hammerspace.com> (raw)
In-Reply-To: <20211212210044.16238-1-richard@nod.at>
On Sun, 2021-12-12 at 22:00 +0100, Richard Weinberger wrote:
> When re-exporting, the whole struct nfs_fh is embedded in the new
> fhandle.
> But we need only nfs_fh->data[], nfs_fh->size is not needed.
> So skip fs_fh->size and save a full word (4 bytes).
> The downside is the extra memcpy() in nfs_fh_to_dentry().
>
> Signed-off-by: Richard Weinberger <richard@nod.at>
> ---
> While investigating into improving NFS re-export I noticed that
> we can already save 4 bytes of overhead.
> I don't think we need to embedd the full struct nfs_fh and
> can skip ->size.
>
NACK. This will break existing running clients. Any code to change the
filehandle format must be accompanied with code to detect and service
filehandles that are presented in the old format.
--
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@hammerspace.com
next prev parent reply other threads:[~2021-12-12 21:20 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-12 21:00 [RFC PATCH] NFS: Save 4 bytes when re-exporting Richard Weinberger
2021-12-12 21:19 ` Trond Myklebust [this message]
2021-12-12 21:32 ` Richard Weinberger
2021-12-12 21:51 ` Richard Weinberger
2021-12-12 21:53 ` Trond Myklebust
2021-12-12 21:57 ` Richard Weinberger
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