svn commit: r291171 - in head/sys: amd64/amd64 compat/ia32 i386/i386 kern sys

[Oliver Pinter]

On Thursday, December 10, 2015, Konstantin Belousov <kostikbel at gmail.com>
wrote:

> On Thu, Dec 10, 2015 at 10:18:19PM +0100, Oliver Pinter wrote:
> > On Mon, Nov 23, 2015 at 8:09 AM, Konstantin Belousov <kib at freebsd.org
> <javascript:;>> wrote:
> > > Author: kib
> > > Date: Mon Nov 23 07:09:35 2015
> > > New Revision: 291171
> > > URL: https://svnweb.freebsd.org/changeset/base/291171
> > >
> > > Log:
> > >   Split kerne timekeep ABI structure vdso_sv_tk out of the struct
> > >   sysentvec.  This allows the timekeep data to be shared between
> similar
> > >   ABIs which cannot share sysentvec.
> > >
> > >   Make the timekeep_push_vdso() tick callback to the timekeep
> structures
> > >   instead of sysentvecs.  If several sysentvec share the vdso_sv_tk
> > >   structure, we would update the userspace data several times on each
> > >   tick, without the change.
> > >
> > >   Only allocate vdso_sv_tk in the exec_sysvec_init() sysinit when
> > >   sysentvec is marked with the new SV_TIMEKEEP flag.  This saves
> > >   allocation and update of unneeded vdso_sv_tk for ABIs which do not
> > >   provide userspace gettimeofday yet, which are PowerPCs arches right
> > >   now.
> > >
> > >   Make vdso_sv_tk allocator public, namely split out and export
> > >   alloc_sv_tk() and alloc_sv_tk_compat32().  ABIs which share timekeep
> > >   data now can allocate it manually and share as appropriate.
> > >
> > >   Requested by: nwhitehorn
> > >   Tested by:    nwhitehorn, pho
> > >   Sponsored by: The FreeBSD Foundation
> > >   MFC after:    2 weeks
> >
> > Hello Konstantin!
> >
> > Do you plan to MFC back this changes to 10-STABLE in these days?
>
> I decided to not merge the change.
>

And if I'm not wrong, the rationale behind this decision is the type
stability of struct sysvec / sysent.