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From:   Pavel Tatashin <pasha.tatashin@oracle.com>
Date:   Wed, 20 Jun 2018 17:30:17 -0400
Message-ID: <CAGM2reZjKxiG+7P65=-sV7PdN_UepGT5QipWFScZ+TpAfDHQqQ@mail.gmail.com>
Subject: Re: [PATCH v10 7/7] x86/tsc: use tsc early
To:     peterz@infradead.org
Cc:     tglx@linutronix.de, Steven Sistare <steven.sistare@oracle.com>,
        Daniel Jordan <daniel.m.jordan@oracle.com>,
        linux@armlinux.org.uk, schwidefsky@de.ibm.com,
        Heiko Carstens <heiko.carstens@de.ibm.com>,
        John Stultz <john.stultz@linaro.org>, sboyd@codeaurora.org,
        x86@kernel.org, LKML <linux-kernel@vger.kernel.org>,
        mingo@redhat.com, hpa@zytor.com, douly.fnst@cn.fujitsu.com,
        prarit@redhat.com, feng.tang@intel.com,
        Petr Mladek <pmladek@suse.com>, gnomes@lxorguk.ukuu.org.uk
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Hi Peter,

> That said; flipping static keys early isn't hard. We should call
> jump_label_init() early, because we want the entries sorted and the
> key->entries link set. It will also replace the GENERIC_NOP5_ATOMIC
> thing, which means we need to also do arch_init_ideal_nop() early, but
> since that is pure CPUID based that should be doable.
>
> And then something like the below could be used.

I like the idea of making static branches available early, as it can
be used in more places
during boot.

However, that should be part of a separate project, and a follow up
cleanup can be done
to places that benefit from it. Such as tsc.c and perhaps sched.c
might benefit as well.

Thank you,
Pavel