Date: Sat, 8 Dec 2012 13:12:19 -0800 From: Alfred Perlstein <bright@mu.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: "stable@freebsd.org" <stable@freebsd.org>, "fs@freebsd.org" <fs@freebsd.org> Subject: Re: nullfs changes MFC Message-ID: <CB178B37-E1E1-422A-8793-FBA16EF5681A@mu.org> In-Reply-To: <20121208010109.GH3013@kib.kiev.ua> References: <20121208010109.GH3013@kib.kiev.ua>
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By combining vop_settext/unset/get into a single call with parameters "op" a= nd &out (for gettext) you can reduce 3 new vops into a single vop.=20 The same can be done for write count vops.=20 This will allow you to preserve kbi by reducing the vop additions to 2.=20 Sent from my iPhone On Dec 7, 2012, at 5:01 PM, Konstantin Belousov <kostikbel@gmail.com> wrote:= > Hi, > I am going to merge latest batch of the nullfs improvements into > stable/9. This will bring up significant performance enchancements due > to use of the shared locks for lookups if the lower layer supports it, > much better caching on the nullfs layer, and proper handling of the text > segments on the nullfs. Also, it should improve the error recovery and > some corner cases with locking. >=20 > Unfortunately, the merge would break KBI for VFS, since it needs 5 new > VOP slots, and only three spares are left. We already are very liberal > with the VFS KBI, so I do not feel that the merge is not acceptable, due > to the benefits it brings to the nullfs. >=20 > The merge is available at=20 > http://people.freebsd.org/~kib/misc/nullfs_9.1.patch
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