From: Vlastimil Babka <vbabka@suse.cz>
To: Stafford Horne <shorne@gmail.com>, linux-kernel@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Kees Cook <keescook@chromium.org>, Jessica Yu <jeyu@redhat.com>,
Petr Mladek <pmladek@suse.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Yang Shi <yang.shi@linaro.org>, Tejun Heo <tj@kernel.org>,
Prarit Bhargava <prarit@redhat.com>,
Yaowei Bai <baiyaowei@cmss.chinamobile.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH -next] init/main: Init jump_labels before they are used to build zonelists
Date: Tue, 17 Jan 2017 14:07:36 +0100 [thread overview]
Message-ID: <cc2486a7-4a95-8014-acfa-0eedf485d935@suse.cz> (raw)
In-Reply-To: <20170117125624.8535-1-shorne@gmail.com>
[+CC PeterZ]
On 01/17/2017 01:56 PM, Stafford Horne wrote:
> A recent change in -next introduced static_keys in init zonelists,
> details are:
>
> Author: Vlastimil Babka <vbabka@suse.cz>
> Date: Thu Jan 12 12:19:03 2017 +1100
> commit f5adbdff6a1c40e19 ("mm, page_alloc: convert
> page_group_by_mobility_disable to static key")
>
> This causes the following warning in openrisc as reported by Guenter,
> and repoduced by me.
>
> WARNING: CPU: 0 PID: 0 at ./include/linux/jump_label.h:198 0xc02d758c
> static_key_slow_inc used before call to jump_label_init
>
> This fixes this by initialized jump_labels even earlier, I am suprized the
> issue is not showing up in other platforms yet.
AFAICS it depends on how much memory is available at that point. But
maybe I just missed the warning somehow.
Anyway I'm not sure if this patch is safe. Hopefully Peter can judge
this better...
> Cc: Vlastimil Babka <vbabka@suse.cz>
> Signed-off-by: Stafford Horne <shorne@gmail.com>
> ---
> init/main.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/init/main.c b/init/main.c
> index 8b1adb6e..d1ca7cb 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -513,6 +513,7 @@ asmlinkage __visible void __init start_kernel(void)
> boot_cpu_state_init();
> smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
>
> + jump_label_init();
> build_all_zonelists(NULL, NULL);
> page_alloc_init();
>
> @@ -526,8 +527,6 @@ asmlinkage __visible void __init start_kernel(void)
> parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
> NULL, set_init_arg);
>
> - jump_label_init();
> -
> /*
> * These use large bootmem allocations and must precede
> * kmem_cache_init()
>
next prev parent reply other threads:[~2017-01-17 13:07 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-17 12:56 [PATCH -next] init/main: Init jump_labels before they are used to build zonelists Stafford Horne
2017-01-17 13:07 ` Vlastimil Babka [this message]
2017-01-17 13:44 ` Peter Zijlstra
2017-01-17 14:30 ` Stafford Horne
2017-01-17 16:11 ` Vlastimil Babka
2017-01-17 20:34 ` Andrew Morton
2017-01-17 20:49 ` Vlastimil Babka
2017-01-19 8:28 ` Vlastimil Babka
2017-01-19 9:56 ` Mel Gorman
2017-01-23 5:54 ` Michael Ellerman
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