Date: Wed, 24 Sep 2014 17:23:39 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: John Baldwin <jhb@freebsd.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, Bryan Drewery <bdrewery@freebsd.org> Subject: Re: svn commit: r272032 - head/sys/conf Message-ID: <20140924142339.GJ8870@kib.kiev.ua> In-Reply-To: <8280436.uSRo73F0Mt@ralph.baldwin.cx> References: <201409231704.s8NH4Lcv098184@svn.freebsd.org> <5421BC8E.6000709@FreeBSD.org> <20140923184434.GG8870@kib.kiev.ua> <8280436.uSRo73F0Mt@ralph.baldwin.cx>
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On Wed, Sep 24, 2014 at 09:58:07AM -0400, John Baldwin wrote: > On Tuesday, September 23, 2014 09:44:34 PM Konstantin Belousov wrote: > > On Tue, Sep 23, 2014 at 01:31:42PM -0500, Bryan Drewery wrote: > > > On 9/23/2014 1:20 PM, Konstantin Belousov wrote: > > > > On Tue, Sep 23, 2014 at 05:04:21PM +0000, Bryan Drewery wrote: > > > >> Author: bdrewery > > > >> Date: Tue Sep 23 17:04:21 2014 > > > >> New Revision: 272032 > > > >> URL: http://svnweb.freebsd.org/changeset/base/272032 > > > >> > > > >> Log: > > > >> DEBUG_LOCKS no longer modifies 'struct vnode', nor does fstat(1) use > > > >> it. > > > >> fstat(1) now uses libprocstat(9). There is no userland impact to > > > >> using this.> > > > > > DEBUG_VFS_LOCKS does modify KBI of VFS, by adding struct stack to > > > > lockmgr, and lockmgr is embedded into each struct vnode. > > > > > > > > VFS modules, in particular, filesystems, compiled for mismatched > > > > kernel WRT DEBUG_VFS_LOCKS, would cause strange breakage. > > > > > > Well, perhaps the comment needs to be updated to state that > > > DEBUG_VFS_LOCKS modifies VFS KBI so any VFS modules will need to > > > recompiled. > > > > > > I did see the stack was moved to lockmgr, but given the use of > > > libprocstat, and lockmgr being a kernel struct, I don't think it's worth > > > mentioning userland here. > > > > > > Sound good? > > > > I agree, I do not think that userland is affected. > > It is for at least lsof (which does not use libprocstat and cannot easily be > adopted to use it exclusively as it pulls a lot more data out than libprocstat > exports such as the info about file locks, etc.) We cannot seriously consider the lsof as application which uses stable interfaces. I.e., binary incompatibility for lsof even on the stable branch or on -pX is not an issue. Lsof verifies kernel release name and warns if it differs from the one used at the compilation time, rightfully.
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