Date: Mon, 11 Sep 2017 10:37:50 +0200 From: Mateusz Guzik <mjguzik@gmail.com> To: Ryan Libby <rlibby@freebsd.org> Cc: Bruce Evans <brde@optusnet.com.au>, Mateusz Guzik <mjg@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org> Subject: Re: svn commit: r323393 - in head/sys: sys vm Message-ID: <CAGudoHH=nGMPwiLJ_bb5OhEjN_u6S=P16snyEUah5i7MzGQmnA@mail.gmail.com> In-Reply-To: <CAHgpiFx-M3=JtZ0iq4CoxoEPMdDUYBS3W5SMaUntkBZZziqGjQ@mail.gmail.com> References: <201709101900.v8AJ0c2N059845@repo.freebsd.org> <20170911111127.B870@besplex.bde.org> <CAGudoHG8yVw46cwmpswnozMf-pSjHtBXHDk8DmJ6v=CwOCvWLg@mail.gmail.com> <CAHgpiFx-M3=JtZ0iq4CoxoEPMdDUYBS3W5SMaUntkBZZziqGjQ@mail.gmail.com>
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On Mon, Sep 11, 2017 at 10:24 AM, Ryan Libby <rlibby@freebsd.org> wrote: > On Mon, Sep 11, 2017 at 12:30 AM, Mateusz Guzik <mjguzik@gmail.com> wrote: > [...] > > That said, looking now at the struct I think its use should be retired > > from the kernel. It can remain in headers for userspace use. > > > > First, there is a bunch of counter(9) fields. I don't know the original > > reasoning. I would expect these counters to be statically defined in a > > per-cpu struct. > > The actual counter(9) counters are per-CPU. These are just offsets into > the PCPU area. See r317061 / D10156 (recent work by glebius). > I mean their ids are allocated on boot, even though these counters are always present and could be resolved at compilation time. So in order to update them you have to fetch the id, as opposed to having the code just do the right thing. I.e. for stuff which is always there we should just have well known offsets into per-cpu tables. But I'm not going to try to flame a patch in (or write one). -- Mateusz Guzik <mjguzik gmail.com>
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