From: Paolo Bonzini <pbonzini@redhat.com>
To: "Radim Krčmář" <rkrcmar@redhat.com>, "Arnd Bergmann" <arnd@arndb.de>
Cc: the arch/x86 maintainers <x86@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Alex Williamson <alex.williamson@redhat.com>,
kvm@vger.kernel.org
Subject: Re: [PATCH 6/8] x86: add MULTIUSER dependency for KVM
Date: Sun, 23 Jul 2017 15:41:58 +0200 [thread overview]
Message-ID: <8ee0dbeb-9a74-1e9a-2500-978f415c8b40@redhat.com> (raw)
In-Reply-To: <20170719161328.GB17303@potion>
On 19/07/2017 18:13, Radim Krčmář wrote:
> Good point, 'select' seems misused here.
>
> There is no reason to depend on TASKSTATS (nor NET+MULTIUSER), we only
> suggest to enable it with KVM. KVM uses sched_info_on() to handle any
> any possible resulting configuration, c9aaa8957f20 ("KVM: Steal time
> implementation").
>
> KVM would work as intended if 'select' would not enable the option if
> its dependencies failed (instead of unconditionally forcing the option).
>
> Is the preferred way to encode it:
>
> 'default y if KVM' in config TASK_DELAY_ACCT
> (that adds a non-local and enigmatic dependency and also needlessly
> expands the possible configuration space)
>
> or
>
> 'select TASKSTATS if NET && MULTIUSER' in config KVM
> (that is going to break when dependencies of TASKSTATS change again)
>
> ?
I think the former is the closest to what the user actually wants, and
it would let us clean up arch/x86/kvm/Kconfig. However it should be
"default y if KVM && X86'.
Maybe there is room for a new operator "suggest Y" which, when added
inside "config X", operates as if "config Y" had a "default y if X".
In this case, kvm could do
- depends on NET && MULTIUSER
- select TASKSTATS
+ suggest TASKSTATS
Thanks,
Paolo
next prev parent reply other threads:[~2017-07-23 13:42 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-19 12:52 [PATCH 0/8] x86: randconfig warning fixes Arnd Bergmann
2017-07-19 12:52 ` [PATCH 1/8] perf/x86: shut up false-positive -Wmaybe-uninitialized warning Arnd Bergmann
2017-07-20 10:24 ` [tip:x86/urgent] perf/x86: Shut " tip-bot for Arnd Bergmann
2017-07-19 12:53 ` [PATCH 2/8] x86: math-emu: possible uninitialized variable use Arnd Bergmann
2017-07-20 10:25 ` [tip:x86/urgent] x86/fpu/math-emu: Fix " tip-bot for Arnd Bergmann
2017-07-19 12:53 ` [PATCH 3/8] x86: math-emu: avoid bogus -Wint-in-bool-context warning Arnd Bergmann
2017-07-20 10:25 ` [tip:x86/urgent] x86/fpu/math-emu: Avoid " tip-bot for Arnd Bergmann
2017-07-19 12:53 ` [PATCH 4/8] x86: io: add "memory" clobber to insb/insw/insl/outsb/outsw/outsl Arnd Bergmann
2017-07-19 19:25 ` Arnd Bergmann
2017-07-19 19:46 ` Linus Torvalds
2017-07-20 10:25 ` [tip:x86/urgent] x86/io: Add " tip-bot for Arnd Bergmann
2017-07-19 12:53 ` [PATCH 5/8] x86: silence build with "make -s" Arnd Bergmann
2017-07-20 10:26 ` [tip:x86/urgent] x86/build: Silence the " tip-bot for Arnd Bergmann
2017-07-19 12:53 ` [PATCH 6/8] x86: add MULTIUSER dependency for KVM Arnd Bergmann
2017-07-19 14:11 ` Radim Krčmář
2017-07-19 14:18 ` Arnd Bergmann
2017-07-19 16:13 ` Radim Krčmář
2017-07-23 13:41 ` Paolo Bonzini [this message]
2017-07-19 12:53 ` [PATCH 7/8] x86: add PCI dependency for PUNIT_ATOM_DEBUG Arnd Bergmann
2017-07-20 10:26 ` [tip:x86/urgent] x86/platform: Add " tip-bot for Arnd Bergmann
2017-07-19 12:53 ` [PATCH 8/8] x86: intel-mid: fix a format string overflow warning Arnd Bergmann
2017-07-20 10:27 ` [tip:x86/urgent] x86/platform/intel-mid: Fix " tip-bot for Arnd Bergmann
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