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Subject: Re: [PATCH 0/2] printk: replace ringbuffer
To:     John Ogness <john.ogness@linutronix.de>
Cc:     Petr Mladek <pmladek@suse.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Andrea Parri <parri.andrea@gmail.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        kexec@lists.infradead.org, linux-kernel@vger.kernel.org
References: <20200128161948.8524-1-john.ogness@linutronix.de>
From:   lijiang <lijiang@redhat.com>
Message-ID: <0f49d4cc-be61-ed0c-5001-2256416fe2ec@redhat.com>
Date:   Thu, 6 Feb 2020 17:21:34 +0800
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=E5=9C=A8 2020=E5=B9=B401=E6=9C=8829=E6=97=A5 00:19, John Ogness =E5=86=99=
=E9=81=93:
> Hello,
>=20
> After several RFC series [0][1][2][3][4], here is the first set of
> patches to rework the printk subsystem. This first set of patches
> only replace the existing ringbuffer implementation. No locking is
> removed. No semantics/behavior of printk are changed.
>=20
> The VMCOREINFO is updated, which will require changes to the
> external crash [5] tool. I will be preparing a patch to add support
> for the new VMCOREINFO.
>=20
In addition to changing the crash utility, I would think that the
kexec-tools(such as the vmcore-dmesg and makedumpfile) also need to
be modified accordingly.

Thanks
Lianbo

> This series is in line with the agreements [6] made at the meeting
> during LPC2019 in Lisbon, with 1 exception: support for dictionaries
> will _not_ be discontinued [7]. Dictionaries are stored in a separate
> buffer so that they cannot interfere with the human-readable buffer.
>=20
> John Ogness
>=20
> [0] https://lkml.kernel.org/r/20190212143003.48446-1-john.ogness@linutr=
onix.de
> [1] https://lkml.kernel.org/r/20190607162349.18199-1-john.ogness@linutr=
onix.de
> [2] https://lkml.kernel.org/r/20190727013333.11260-1-john.ogness@linutr=
onix.de
> [3] https://lkml.kernel.org/r/20190807222634.1723-1-john.ogness@linutro=
nix.de
> [4] https://lkml.kernel.org/r/20191128015235.12940-1-john.ogness@linutr=
onix.de
> [5] https://github.com/crash-utility/crash
> [6] https://lkml.kernel.org/r/87k1acz5rx.fsf@linutronix.de
> [7] https://lkml.kernel.org/r/20191007120134.ciywr3wale4gxa6v@pathway.s=
use.cz
>=20
> John Ogness (2):
>   printk: add lockless buffer
>   printk: use the lockless ringbuffer
>=20
>  include/linux/kmsg_dump.h         |    2 -
>  kernel/printk/Makefile            |    1 +
>  kernel/printk/printk.c            |  836 +++++++++---------
>  kernel/printk/printk_ringbuffer.c | 1370 +++++++++++++++++++++++++++++
>  kernel/printk/printk_ringbuffer.h |  328 +++++++
>  5 files changed, 2114 insertions(+), 423 deletions(-)
>  create mode 100644 kernel/printk/printk_ringbuffer.c
>  create mode 100644 kernel/printk/printk_ringbuffer.h
>=20