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From:   Kurt Kanzenbach <kurt@linutronix.de>
To:     Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Adhemerval Zanella <adhemerval.zanella@linaro.org>,
        Lukasz Majewski <lukma@denx.de>,
        Florian Weimer <fweimer@redhat.com>,
        Carlos O'Donell <carlos@redhat.com>,
        "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>,
        Davidlohr Bueso <dave@stgolabs.net>,
        Ingo Molnar <mingo@kernel.org>,
        Darren Hart <dvhart@infradead.org>,
        Andrei Vagin <avagin@gmail.com>
Subject: Re: [patch 0/6] futex: Bugfixes and FUTEX_LOCK_PI2
In-Reply-To: <YJKWt2vlr74WR5tx@hirez.programming.kicks-ass.net>
References: <20210422194417.866740847@linutronix.de>
 <YJKWt2vlr74WR5tx@hirez.programming.kicks-ass.net>
Date:   Wed, 05 May 2021 15:51:18 +0200
Message-ID: <87r1ilp9ux.fsf@kurt>
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On Wed May 05 2021, Peter Zijlstra wrote:
> It's all somewhat sad, but I don't see any other way out of this. Using
> LOCK_PI2 will be a fairly horrible pile of hacks on the userspace side
> of things given they need to first detect it's presence etc., but that
> seems unavoidable whatever we do :/

Well, that's the interesting point. I do have such horrible hacks for
glibc, which detect the presence of LOCK_PI2 at run time. However, the
glibc has also the notion of kernel features based on the Linux kernel
version. Then, it could be detected at compile time. At the end of the
day it depends on how this patch set is merged. I was hoping for the
glibc folks to share their opinion on this :-).

Thanks,
Kurt

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