Re: [PATCH v2 2/2] rusage: allow 64-bit times ru_utime/ru_stime

From: Ingo Molnar <mingo@kernel.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: y2038 Mailman List <y2038@lists.linaro.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	the arch/x86 maintainers <x86@kernel.org>,
	Linux API <linux-api@vger.kernel.org>,
	linux-arch <linux-arch@vger.kernel.org>,
	Paul Eggert <eggert@cs.ucla.edu>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	Richard Henderson <rth@twiddle.net>,
	Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
	Matt Turner <mattst88@gmail.com>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Dominik Brodowski <linux@dominikbrodowski.net>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-alpha@vger.kernel.org,
	Deepa Dinamani <deepa.kernel@gmail.com>
Subject: Re: [PATCH v2 2/2] rusage: allow 64-bit times ru_utime/ru_stime
Date: Thu, 21 Jun 2018 18:11:21 +0200	[thread overview]
Message-ID: <20180621161121.GB7222@gmail.com> (raw)
In-Reply-To: <CAK8P3a1QYTfRNQt2+a29BpvgYM_pnSFrO=NBvVo=BdUa2q9ngQ@mail.gmail.com>

* Arnd Bergmann <arnd@arndb.de> wrote:

> Sure, no problem. Do you have an opinion on the question I raised in the
> first patch [1], i.e. whether we actually want this to be done this way in the
> kernel, or one of the other approaches I described there?

So this looks like the most forward looking variant:

> a) deprecate the wait4() and getrusage() system calls, and create
>    a set of kernel interfaces based around a newly defined structure that
>    could solve multiple problems at once, e.g. provide more fine-grained
>    timestamps. The C library could then implement the posix interfaces
>    on top of the new system calls.

... but given the pretty long propagation time of new ABIs, is this a good 
solution? What would the limitations/trade-offs be on old-ABI systems?

Thanks,

	Ingo