linux-kernel - Re: [PATCH] random: do not use jump labels before they are initialized

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Message-ID: <Yp839NjwW3scZEqi@zx2c4.com>
Date:   Tue, 7 Jun 2022 13:35:16 +0200
From:   "Jason A. Donenfeld" <Jason@...c4.com>
To:     Ard Biesheuvel <ardb@...nel.org>
Cc:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        Stephen Boyd <swboyd@...omium.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Russell King <linux@...linux.org.uk>,
        Arnd Bergmann <arnd@...db.de>,
        Phil Elwell <phil@...pberrypi.com>
Subject: Re: [PATCH] random: do not use jump labels before they are
 initialized

Hi Ard,

On Tue, Jun 07, 2022 at 01:10:52PM +0200, Ard Biesheuvel wrote:
> Fair enough. What I would like is to remove the need to play around
> with the placement of jump_label_init() across architectures. Jump
> labels are fundamentally a performance optimization, so unless you can
> explain how setting it as early as possible makes a material
> difference, performance or otherwise, I really think we should pursue
> a solution that does the static key manipulation at some later time.

Alright. It sounds like Catalin also prefers the same. This seems simple
enough with minimal downsides: https://lore.kernel.org/lkml/20220607113238.769088-1-Jason@zx2c4.com/

So maybe we should just go that route.

Jason