From: Andrew Morton <akpm@linux-foundation.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: linux-kernel@vger.kernel.org, Guenter Roeck <groeck@google.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Thomas Gleixner <tglx@linutronix.de>,
Mike Rapoport <rppt@linux.ibm.com>,
linux-mm@kvack.org
Subject: Re: [PATCH] init: Initialize jump labels before command line option parsing
Date: Tue, 16 Apr 2019 16:44:18 -0700 [thread overview]
Message-ID: <20190416164418.3ca1d8cef2713a1154067291@linux-foundation.org> (raw)
In-Reply-To: <155544804466.1032396.13418949511615676665.stgit@dwillia2-desk3.amr.corp.intel.com>
On Tue, 16 Apr 2019 13:54:04 -0700 Dan Williams <dan.j.williams@intel.com> wrote:
> When a module option, or core kernel argument, toggles a static-key it
> requires jump labels to be initialized early. While x86, PowerPC, and
> ARM64 arrange for jump_label_init() to be called before parse_args(),
> ARM does not.
>
> Kernel command line: rdinit=/sbin/init page_alloc.shuffle=1 panic=-1 console=ttyAMA0,115200 page_alloc.shuffle=1
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 0 at ./include/linux/jump_label.h:303
> page_alloc_shuffle+0x12c/0x1ac
> static_key_enable(): static key 'page_alloc_shuffle_key+0x0/0x4' used
> before call to jump_label_init()
> Modules linked in:
> CPU: 0 PID: 0 Comm: swapper Not tainted
> 5.1.0-rc4-next-20190410-00003-g3367c36ce744 #1
> Hardware name: ARM Integrator/CP (Device Tree)
> [<c0011c68>] (unwind_backtrace) from [<c000ec48>] (show_stack+0x10/0x18)
> [<c000ec48>] (show_stack) from [<c07e9710>] (dump_stack+0x18/0x24)
> [<c07e9710>] (dump_stack) from [<c001bb1c>] (__warn+0xe0/0x108)
> [<c001bb1c>] (__warn) from [<c001bb88>] (warn_slowpath_fmt+0x44/0x6c)
> [<c001bb88>] (warn_slowpath_fmt) from [<c0b0c4a8>]
> (page_alloc_shuffle+0x12c/0x1ac)
> [<c0b0c4a8>] (page_alloc_shuffle) from [<c0b0c550>] (shuffle_store+0x28/0x48)
> [<c0b0c550>] (shuffle_store) from [<c003e6a0>] (parse_args+0x1f4/0x350)
> [<c003e6a0>] (parse_args) from [<c0ac3c00>] (start_kernel+0x1c0/0x488)
>
> Move the fallback call to jump_label_init() to occur before
> parse_args(). The redundant calls to jump_label_init() in other archs
> are left intact in case they have static key toggling use cases that are
> even earlier than option parsing.
Has it been confirmed that this fixes
mm-shuffle-initial-free-memory-to-improve-memory-side-cache-utilization.patch
on beaglebone-black?
next prev parent reply other threads:[~2019-04-16 23:44 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-16 20:54 Dan Williams
2019-04-16 23:44 ` Andrew Morton [this message]
2019-04-17 0:04 ` Dan Williams
2019-04-17 0:39 ` Guenter Roeck
2019-04-17 3:24 ` Andrew Morton
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190416164418.3ca1d8cef2713a1154067291@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=dan.j.williams@intel.com \
--cc=groeck@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=rppt@linux.ibm.com \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox