LKML Archive on lore.kernel.org
 help / color / Atom feed
From: John Ogness <john.ogness@linutronix.de>
To: linux-kernel@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>,
	Petr Mladek <pmladek@suse.com>,
	Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Andrea Parri <andrea.parri@amarulasolutions.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Brendan Higgins <brendanhiggins@google.com>
Subject: [RFC PATCH v4 0/9] printk: new ringbuffer implementation
Date: Thu,  8 Aug 2019 00:32:25 +0206
Message-ID: <20190807222634.1723-1-john.ogness@linutronix.de> (raw)

Hello,

This is a follow-up RFC on the work to re-implement much of
the core of printk. The threads for the previous RFC versions
are here: v1[0], v2[1], v3[2].

This series only builds upon v3 (i.e. the first part of this
series is exactly v3). The main purpose of this series is to
replace the current printk ringbuffer with the new
ringbuffer. As was discussed[3], this is a conservative
first step to rework printk. For example, all logbuf_lock
usage is kept even though the new ringbuffer does not
require it. This avoids any side-effect bugs in case the
logbuf_lock is (unintentionally) synchronizing more than
just the ringbuffer. However, this also means that the
series does not bring any improvements, just swapping out
implementations. A future patch will remove the logbuf_lock.

Except for the test module (patches 2 and 6), the rest may
already be interesting for mainline as is. I have tested
the various interfaces (console, /dev/kmsg, syslog,
kmsg_dump) and their features and all looks good AFAICT.

The patches can be broken down as follows:

1-2: the previously posted RFCv3

3-7: addresses minor issues from RFCv3

8:   adds new high-level ringbuffer functions to support
     printk (nothing involving new memory barriers)

9:   replace the ringbuffer usage in printk.c

One important thing to know (as is mentioned in the commit
message of patch 9), there are 2 externally visible
changes:

    - vmcore info changes

    - powerpc powernv/opal memdump of log discontinued

I have no idea how acceptable these changes are.

I will not be posting any further printk patches until I
have received some feedback on this. I appreciate all the
help so far. I realize that this is a lot of code to go
through.

The series is based on 5.3-rc3. I would encourage people to
apply the series and give it a run. I expect that you
will not notice any difference with your printk behaviour.

John Ogness

[0] https://lkml.kernel.org/r/20190212143003.48446-1-john.ogness@linutronix.de
[1] https://lkml.kernel.org/r/20190607162349.18199-1-john.ogness@linutronix.de
[2] https://lkml.kernel.org/r/20190727013333.11260-1-john.ogness@linutronix.de
[3] https://lkml.kernel.org/r/87y35hn6ih.fsf@linutronix.de

John Ogness (9):
  printk-rb: add a new printk ringbuffer implementation
  printk-rb: add test module
  printk-rb: fix missing includes/exports
  printk-rb: initialize new descriptors as invalid
  printk-rb: remove extra data buffer size allocation
  printk-rb: adjust test module ringbuffer sizes
  printk-rb: increase size of seq and size variables
  printk-rb: new functionality to support printk
  printk: use a new ringbuffer implementation

 arch/powerpc/platforms/powernv/opal.c |   22 +-
 include/linux/kmsg_dump.h             |    6 +-
 include/linux/printk.h                |   12 -
 kernel/printk/Makefile                |    5 +
 kernel/printk/dataring.c              |  809 ++++++++++++++++++
 kernel/printk/dataring.h              |  108 +++
 kernel/printk/numlist.c               |  376 +++++++++
 kernel/printk/numlist.h               |   72 ++
 kernel/printk/printk.c                |  745 +++++++++--------
 kernel/printk/ringbuffer.c            | 1079 +++++++++++++++++++++++++
 kernel/printk/ringbuffer.h            |  354 ++++++++
 kernel/printk/test_prb.c              |  256 ++++++
 12 files changed, 3450 insertions(+), 394 deletions(-)
 create mode 100644 kernel/printk/dataring.c
 create mode 100644 kernel/printk/dataring.h
 create mode 100644 kernel/printk/numlist.c
 create mode 100644 kernel/printk/numlist.h
 create mode 100644 kernel/printk/ringbuffer.c
 create mode 100644 kernel/printk/ringbuffer.h
 create mode 100644 kernel/printk/test_prb.c

-- 
2.20.1


             reply index

Thread overview: 131+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-07 22:26 John Ogness [this message]
2019-08-07 22:26 ` [RFC PATCH v4 1/9] printk-rb: add a new printk " John Ogness
2019-08-20  8:15   ` numlist_pop(): " Petr Mladek
2019-08-21  5:41     ` John Ogness
2019-09-04 12:19     ` Peter Zijlstra
2019-08-20  8:22   ` assign_desc() barriers: " Petr Mladek
2019-08-20 14:14     ` Petr Mladek
2019-08-21  5:52       ` John Ogness
2019-08-22 11:53         ` Petr Mladek
2019-08-25  2:06           ` John Ogness
2019-08-26  8:21             ` John Ogness
2019-08-20  8:55   ` comments style: " Petr Mladek
2019-08-20  9:27     ` Sergey Senozhatsky
2019-08-21  5:46       ` John Ogness
2019-08-22 13:50         ` Petr Mladek
2019-08-22 17:38           ` Andrea Parri
2019-08-23 10:47             ` Petr Mladek
2019-08-23 14:27               ` Andrea Parri
2019-08-23  9:49           ` Sergey Senozhatsky
2019-08-23  5:54         ` Sergey Senozhatsky
2019-08-23 10:29           ` Petr Mladek
2019-08-21  5:42     ` John Ogness
2019-08-22 12:44       ` Petr Mladek
2019-08-20 13:50   ` dataring_push() barriers " Petr Mladek
2019-08-25  2:42     ` John Ogness
2019-08-27 14:36       ` Petr Mladek
2019-08-28 13:43         ` John Ogness
2019-08-20 15:12   ` datablock reuse races " Petr Mladek
2019-08-23  9:21   ` numlist_push() barriers " Petr Mladek
2019-08-26  8:34     ` Andrea Parri
2019-08-26  8:43       ` Andrea Parri
2019-08-26 14:10       ` Petr Mladek
2019-08-26 16:01         ` Andrea Parri
2019-08-26 22:36     ` John Ogness
2019-08-27  7:40       ` Petr Mladek
2019-08-27 14:28         ` John Ogness
2019-08-27 15:07           ` Petr Mladek
2019-08-28 10:24             ` John Ogness
2019-08-23 17:18   ` numlist API " Petr Mladek
2019-08-26 23:57     ` John Ogness
2019-08-27 13:03       ` Petr Mladek
2019-08-28  7:13         ` John Ogness
2019-08-28  8:58           ` Petr Mladek
2019-08-28 14:03             ` John Ogness
2019-08-29 11:28               ` Petr Mladek
2019-09-03  7:58         ` Sergey Senozhatsky
2019-08-30 14:48   ` dataring " Petr Mladek
2019-08-07 22:26 ` [RFC PATCH v4 2/9] printk-rb: add test module John Ogness
2019-08-07 22:26 ` [RFC PATCH v4 3/9] printk-rb: fix missing includes/exports John Ogness
2019-08-07 22:26 ` [RFC PATCH v4 4/9] printk-rb: initialize new descriptors as invalid John Ogness
2019-08-20  9:23   ` Petr Mladek
2019-08-20 10:16     ` Sergey Senozhatsky
2019-08-21  5:56     ` John Ogness
2019-08-07 22:26 ` [RFC PATCH v4 5/9] printk-rb: remove extra data buffer size allocation John Ogness
2019-08-07 22:26 ` [RFC PATCH v4 6/9] printk-rb: adjust test module ringbuffer sizes John Ogness
2019-08-19 21:29   ` [PATCH] printk-rb: fix test module macro usage John Ogness
2019-08-07 22:26 ` [RFC PATCH v4 7/9] printk-rb: increase size of seq and size variables John Ogness
2019-08-07 22:26 ` [RFC PATCH v4 8/9] printk-rb: new functionality to support printk John Ogness
2019-08-20  9:59   ` Sergey Senozhatsky
2019-08-21  5:47     ` John Ogness
2019-08-07 22:26 ` [RFC PATCH v4 9/9] printk: use a new ringbuffer implementation John Ogness
2019-08-08 19:07   ` Linus Torvalds
2019-08-08 22:55     ` John Ogness
2019-08-08 23:33       ` Linus Torvalds
2019-08-08 23:45         ` Steven Rostedt
2019-08-09  0:21           ` Linus Torvalds
2019-08-09  0:48             ` Steven Rostedt
2019-08-09  1:15               ` Linus Torvalds
2019-08-09 11:15                 ` Thomas Gleixner
2019-08-09 16:00                   ` Linus Torvalds
2019-08-09 20:07                     ` Thomas Gleixner
2019-08-09 20:20                       ` Linus Torvalds
2019-08-09  6:14     ` Peter Zijlstra
2019-08-09  7:08       ` John Ogness
2019-08-09 15:57       ` Linus Torvalds
2019-08-10  5:53         ` Thomas Gleixner
2019-09-10  3:19           ` Sergey Senozhatsky
2019-08-12  9:54       ` Geert Uytterhoeven
2019-08-16  5:46   ` Dave Young
2019-08-16  5:54     ` Dave Young
2019-08-16  9:40     ` John Ogness
2019-09-04 12:35 ` [RFC PATCH v4 0/9] printk: " Peter Zijlstra
2019-09-05 13:05   ` Petr Mladek
2019-09-05 14:31     ` Peter Zijlstra
2019-09-05 15:38       ` Thomas Gleixner
2019-09-05 16:11         ` Steven Rostedt
2019-09-05 21:10           ` John Ogness
2019-09-06  9:39           ` Petr Mladek
2019-09-09 14:11           ` printk meeting at LPC Thomas Gleixner
2019-09-13 13:26             ` John Ogness
2019-09-13 14:48               ` Daniel Vetter
2019-09-15 13:47                 ` John Ogness
2019-09-16  8:44                   ` Daniel Vetter
2019-09-16  4:30               ` Tetsuo Handa
2019-09-16 10:46                 ` Petr Mladek
2019-09-16 13:43                   ` Steven Rostedt
2019-09-16 14:28                     ` John Ogness
2019-09-17  8:11                       ` Petr Mladek
2019-09-17  7:52                     ` Petr Mladek
2019-09-17 13:02                       ` Steven Rostedt
2019-09-17 13:12                         ` Greg Kroah-Hartman
2019-09-17 13:37                           ` Steven Rostedt
2019-09-17 14:08                             ` Tetsuo Handa
2019-09-17  7:51                   ` Sergey Senozhatsky
2019-09-18  1:25               ` Sergey Senozhatsky
2019-09-18  2:08                 ` Steven Rostedt
2019-09-18  2:36                   ` Sergey Senozhatsky
2019-09-18  5:19                     ` Sergey Senozhatsky
2019-09-18  7:42                       ` John Ogness
2019-09-18  8:10                         ` Sergey Senozhatsky
2019-09-18  9:05                           ` John Ogness
2019-09-18  9:11                             ` Sergey Senozhatsky
2019-09-18 16:41                             ` Petr Mladek
2019-09-18 16:48                               ` Steven Rostedt
2019-09-24 14:24                                 ` Petr Mladek
2019-09-19  8:06                         ` Daniel Vetter
2019-09-18  7:33                     ` John Ogness
2019-09-18  8:08                       ` Sergey Senozhatsky
2019-10-04 14:48               ` Tony Asleson
2019-10-07 12:01                 ` Petr Mladek
2019-09-06  9:06       ` [RFC PATCH v4 0/9] printk: new ringbuffer implementation Peter Zijlstra
2019-09-06 10:09         ` Sergey Senozhatsky
2019-09-06 10:49           ` Peter Zijlstra
2019-09-06 13:44             ` Sergey Senozhatsky
2019-09-06 12:42         ` Petr Mladek
2019-09-06 14:01           ` Peter Zijlstra
2019-09-06 14:22             ` Peter Zijlstra
2019-09-06 19:53             ` Sergey Senozhatsky
2019-09-06 22:47             ` John Ogness
2019-09-08 22:18             ` Peter Zijlstra
2019-09-10  3:22             ` Sergey Senozhatsky

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=20190807222634.1723-1-john.ogness@linutronix.de \
    --to=john.ogness@linutronix.de \
    --cc=andrea.parri@amarulasolutions.com \
    --cc=brendanhiggins@google.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=peterz@infradead.org \
    --cc=pmladek@suse.com \
    --cc=rostedt@goodmis.org \
    --cc=sergey.senozhatsky.work@gmail.com \
    --cc=sergey.senozhatsky@gmail.com \
    --cc=tglx@linutronix.de \
    --cc=torvalds@linux-foundation.org \
    /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

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git