Date: Sun, 6 Oct 2024 07:56:01 -0600 From: Warner Losh <imp@bsdimp.com> To: Konstantin Belousov <kostikbel@gmail.com> Cc: =?UTF-8?Q?Dag=2DErling_Sm=C3=B8rgrav?= <des@freebsd.org>, Mark Millard <marklmi@yahoo.com>, Current FreeBSD <freebsd-current@freebsd.org>, dev-commits-src-main@freebsd.org Subject: Re: git: 2c1963d46335 - main - procfs rlimit: handle pipebuf [and related] :pipebuf . . . Invalid argument Message-ID: <CANCZdfqrztL99d7A%2BMXtkRsuWmvkycOXNgOLEsy_w9xVwf%2BZ8w@mail.gmail.com> In-Reply-To: <ZwJTz6OhoCaEWnnV@kib.kiev.ua> References: <34434D36-A751-477A-8596-72A564113FB8.ref@yahoo.com> <34434D36-A751-477A-8596-72A564113FB8@yahoo.com> <ZwIuobzcUZxm-H0y@kib.kiev.ua> <86r08tvcb0.fsf@ltc.des.dev> <ZwJTz6OhoCaEWnnV@kib.kiev.ua>
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--00000000000082a4f30623cf449d Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Sun, Oct 6, 2024 at 3:09=E2=80=AFAM Konstantin Belousov <kostikbel@gmail= .com> wrote: > On Sun, Oct 06, 2024 at 10:57:23AM +0200, Dag-Erling Sm=C3=B8rgrav wrote: > > Konstantin Belousov <kostikbel@gmail.com> writes: > > > We do not provide forward compatibility between kernel and userspace. > > > User binaries must be newer than kernel. > > > > Uh, no. The opposite, in fact. > > Right, it is opposite. It was a typo. > > Anyway, __FreeBSD_version is not about compatibility between specific > snapshot of kernel and user sources. It de-facto provides two technical > measures: > 1. kernel refuses to load modules built against headers set with higher > __FreeBSD_version than kernel > 2. Some values of __FreeBSD_version are used by userspace to > detect if specific change is present in kernel. See sys/param.h > P_OSREL_ list. > 3. It's used extensively in 3rd party software to select different interfaces (including ports). That's why we document why we do each bump. While 'forward compatibility' is sometimes needed / provided when it adversely affects upgrade from source and fall back to prior kernel while it's worked out. But (a) ZFS BEs eliminate many problems and (b) we've only done it when it was impossible to run buildkernel / git (or svn or cvs in the past) to fix the problem. While the messages are annoying, they don't prevent that limited exception we've occasionally done in the past. In general, we've avoided changes so incompatible that they've needed a new P_OSREL_ entry to cope... Warner --00000000000082a4f30623cf449d Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable <div dir=3D"ltr"><div dir=3D"ltr"><br></div><br><div class=3D"gmail_quote">= <div dir=3D"ltr" class=3D"gmail_attr">On Sun, Oct 6, 2024 at 3:09=E2=80=AFA= M Konstantin Belousov <<a href=3D"mailto:kostikbel@gmail.com">kostikbel@= gmail.com</a>> wrote:<br></div><blockquote class=3D"gmail_quote" style= =3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding= -left:1ex">On Sun, Oct 06, 2024 at 10:57:23AM +0200, Dag-Erling Sm=C3=B8rgr= av wrote:<br> > Konstantin Belousov <<a href=3D"mailto:kostikbel@gmail.com" target= =3D"_blank">kostikbel@gmail.com</a>> writes:<br> > > We do not provide forward compatibility between kernel and usersp= ace.<br> > > User binaries must be newer than kernel.<br> > <br> > Uh, no.=C2=A0 The opposite, in fact.<br> <br> Right, it is opposite.=C2=A0 It was a typo.<br> <br> Anyway, __FreeBSD_version is not about compatibility between specific<br> snapshot of kernel and user sources.=C2=A0 It de-facto provides two technic= al<br> measures:<br> 1. kernel refuses to load modules built against headers set with higher<br> =C2=A0 =C2=A0__FreeBSD_version than kernel<br> 2. Some values of __FreeBSD_version are used by userspace to<br> =C2=A0 =C2=A0detect if specific change is present in kernel.=C2=A0 See sys/= param.h<br> =C2=A0 =C2=A0P_OSREL_ list.<br></blockquote><div><br></div><div>3. It's= used extensively in 3rd party software to select different interfaces</div= ><div>(including ports). That's why we document why we do each bump.</d= iv><div><br></div><div>While 'forward compatibility' is sometimes n= eeded / provided when it</div><div>adversely affects upgrade from source an= d fall back to prior kernel while</div><div>it's worked out. But (a) ZF= S BEs eliminate many problems and (b) we've</div><div>only done it when= it was impossible to run buildkernel / git (or svn or cvs</div><div>in the= past) to fix the problem. While the messages are annoying, they</div><div>= don't prevent that limited exception we've occasionally done in the= past.</div><div>In general, we've avoided changes so incompatible that= they've needed</div><div>a new P_OSREL_ entry to cope...</div><div><br= ></div><div>Warner=C2=A0</div></div></div> --00000000000082a4f30623cf449d--
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