Date: Tue, 14 Dec 2010 08:03:59 +0100 From: Pawel Jakub Dawidek <pjd@FreeBSD.org> To: Steven Hartland <killing@multiplay.co.uk> Cc: freebsd-fs@FreeBSD.org, freebsd-current@FreeBSD.org Subject: Re: Next ZFSv28 patchset ready for testing. Message-ID: <20101214070359.GL2038@garage.freebsd.pl> In-Reply-To: <461DD46B04234127AC0984F945FF6CA6@multiplay.co.uk> References: <20101213214556.GC2038@garage.freebsd.pl> <461DD46B04234127AC0984F945FF6CA6@multiplay.co.uk>
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On Mon, Dec 13, 2010 at 11:00:31PM -0000, Steven Hartland wrote:
> What's the expected behaviour for the sendfile changes as
> sendfile is one of the problems we have here with the
> double memory allocation required for it under ZFS compared
> to UFS. Does this patch address that?
No. The patch doesn't address that. It only adds support for
sendfile(2), as it was commented out in the previous patchset.
> Inspecting the patch the following segment looks odd:-
> --- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c.orig
> +++ sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
> ...
> while (n > 0) {
> nbytes =3D MIN(n, zfs_read_chunk_size -
> P2PHASE(uio->uio_loffset, zfs_read_chunk_size));
>=20
> +#ifdef __FreeBSD__
> + if (uio->uio_segflg =3D=3D UIO_NOCOPY)
> + error =3D mappedread_sf(vp, nbytes, uio);
> + else
> +#endif /* __FreeBSD__ */
> if (vn_has_cached_data(vp))
> error =3D mappedread(vp, nbytes, uio);
> else
>=20
> Is there an extra "else" in there which will break things or should
> the __FreeBSD__ mappedread_sf block replace the standard mappedread
> call or is the indentation just a bit weird?
The code is correct. It is just hard to split 'else' and 'if' with a
'#endif' and keep the indentation pretty. Depends on the conditions we
use one of the three methods to read the data.
--=20
Pawel Jakub Dawidek http://www.wheelsystems.com
pjd@FreeBSD.org http://www.FreeBSD.org
FreeBSD committer Am I Evil? Yes, I Am!
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