Date: Thu, 8 Dec 2016 13:07:06 +1100 (EST) From: Bruce Evans <brde@optusnet.com.au> To: Warner Losh <imp@bsdimp.com> Cc: Gleb Smirnoff <glebius@freebsd.org>, Mark Johnston <markj@freebsd.org>, src-committers <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: r309658 - head/sys/vm Message-ID: <20161208123844.B935@besplex.bde.org> In-Reply-To: <CANCZdfonWLwGnJWZ74r1mvQ5mA0_jEzQUAd0TsKvycsmHQ2seg@mail.gmail.com> References: <201612062252.uB6Mqjhr019191@repo.freebsd.org> <20161207212647.GO27748@FreeBSD.org> <CANCZdfonWLwGnJWZ74r1mvQ5mA0_jEzQUAd0TsKvycsmHQ2seg@mail.gmail.com>
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On Wed, 7 Dec 2016, Warner Losh wrote: > On Wed, Dec 7, 2016 at 2:26 PM, Gleb Smirnoff <glebius@freebsd.org> wrote: >> On Tue, Dec 06, 2016 at 10:52:45PM +0000, Mark Johnston wrote: >> M> Author: markj >> M> Date: Tue Dec 6 22:52:45 2016 >> M> New Revision: 309658 >> M> URL: https://svnweb.freebsd.org/changeset/base/309658 >> M> >> M> Log: >> M> Provide dummy sysctls for v_cache_count and v_tcached. >> M> >> M> Some utilities (notably top(1)) exit if any of their input sysctls don't >> M> exist, and the removal of the above-mentioned PG_CACHE-related sysctls >> M> makes it difficult to run such utilities on different versions of the >> M> kernel without recompiling. >> M> >> M> Requested by: bde >> M> >> M> Modified: >> M> head/sys/vm/vm_meter.c >> M> >> M> Modified: head/sys/vm/vm_meter.c >> M> ============================================================================== >> M> --- head/sys/vm/vm_meter.c Tue Dec 6 22:48:28 2016 (r309657) >> M> +++ head/sys/vm/vm_meter.c Tue Dec 6 22:52:45 2016 (r309658) >> M> @@ -314,3 +314,14 @@ VM_STATS_VM(v_forkpages, "VM pages affec >> M> VM_STATS_VM(v_vforkpages, "VM pages affected by vfork()"); >> M> VM_STATS_VM(v_rforkpages, "VM pages affected by rfork()"); >> M> VM_STATS_VM(v_kthreadpages, "VM pages affected by fork() by kernel"); >> M> + >> M> +#ifndef BURN_BRIDGES >> M> +/* >> M> + * Provide compatibility sysctls for the benefit of old utilities which exit >> M> + * with an error if they cannot be found. >> M> + */ >> M> +SYSCTL_UINT(_vm_stats_vm, OID_AUTO, v_cache_count, CTLFLAG_RD, >> M> + (u_int *)NULL, 0, "Dummy for compatibility"); >> M> +SYSCTL_UINT(_vm_stats_vm, OID_AUTO, v_tcached, CTLFLAG_RD, >> M> + (u_int *)NULL, 0, "Dummy for compatibility"); >> M> +#endif >> >> IMHO, there should be some garbage collecting timeout for them. I'd suggest to >> delete them from head after stable/12 branch is forked. > > Other places define #if BURN_BRUDGES < 1200000 to make this automatic. The correct ifdef is something like '#if COMPAT_FREEBSD12' to make this non-automatic. Support for this option should of course be removed some time after the support for COMPAT_43 option. That is only 25-30 years old. FreeBSD never imported the rather large COMPAT_42 support from 4.4BSD-Lite (except for TCP_COMPAT_42) since it never supported the arches that needed it, but it still had 1 COMPAT_42 ifdef in udp_usrreq.c until 2002. That ifdef was garbage since the option was not supported (not in conf/options). It was for a sysctl too, but less needed since it was only for the default value. Bruce
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