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Linus Torvalds 5c2992ee7f printk: remove console flushing special cases for partial buffered lines
It actively hurts proper merging, and makes for a lot of special cases.
There was a good(ish) reason for doing it originally, but it's getting
too painful to maintain.  And most of the original reasons for it are
long gone.

So instead of having special code to flush partial lines to the console
(as opposed to the record buffers), do _all_ the console writing from
the record buffer, and be done with it.

If an oops happens (or some other synchronous event), we will flush the
partial lines due to the oops printing activity, so this does not affect
that.  It does mean that if you have a completely hung machine, a
partial preceding line may not have been printed out.

That was some of the original reason for this complexity, in fact, back
when we used to test for the historical i386 "halt" instruction problem
by doing

	pr_info("Checking 'hlt' instruction... ");

	if (!boot_cpu_data.hlt_works_ok) {
		pr_cont("disabled\n");
		return;
	}
	halt();
	halt();
	halt();
	halt();
	pr_cont("OK\n");

and that model no longer works (it the 'hlt' instruction kills the
machine, the partial line won't have been flushed, so you won't even see
it).

Of course, that was also back in the days when people actually had
textual console output rather than a graphical splash-screen at bootup.
How times change..

Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Joe Perches <joe@perches.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Tested-by: Petr Mladek <pmladek@suse.com>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-14 21:08:18 -08:00
Documentation Various small fixes for IPMI. Cleanups in the documentation and 2016-12-14 20:54:33 -08:00
arch dmaengine updates for 4.10-rc1 2016-12-14 20:42:45 -08:00
block Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2016-12-14 17:21:53 -08:00
certs certs: Add a secondary system keyring that can be added to dynamically 2016-04-11 22:48:09 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2016-12-14 13:31:29 -08:00
drivers Various small fixes for IPMI. Cleanups in the documentation and 2016-12-14 20:54:33 -08:00
firmware WHENCE: use https://linuxtv.org for LinuxTV URLs 2015-12-04 10:35:11 -02:00
fs Merge branch 'akpm' (patches from Andrew) 2016-12-14 17:25:18 -08:00
include dmaengine updates for 4.10-rc1 2016-12-14 20:42:45 -08:00
init Modules updates for v4.10 2016-12-14 20:12:43 -08:00
ipc ipc/sem: avoid idr tree lookup for interrupted semop 2016-12-14 16:04:08 -08:00
kernel printk: remove console flushing special cases for partial buffered lines 2016-12-14 21:08:18 -08:00
lib radix-tree: ensure counts are initialised 2016-12-14 16:04:10 -08:00
mm Merge branch 'akpm' (patches from Andrew) 2016-12-14 17:25:18 -08:00
net Merge branch 'akpm' (patches from Andrew) 2016-12-14 17:25:18 -08:00
samples Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2016-12-14 13:57:44 -08:00
scripts Modules updates for v4.10 2016-12-14 20:12:43 -08:00
security Merge branch 'akpm' (patches from Andrew) 2016-12-14 17:25:18 -08:00
sound sound updates for 4.10-rc1 2016-12-14 11:14:28 -08:00
tools Merge branch 'akpm' (patches from Andrew) 2016-12-14 17:25:18 -08:00
usr initramfs: allow again choice of the embedded initram compression algorithm 2016-12-14 16:04:08 -08:00
virt mm: unexport __get_user_pages_unlocked() 2016-12-14 16:04:09 -08:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2016-08-02 16:48:52 -04:00
.mailmap Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2016-10-15 09:26:12 -07:00
COPYING [PATCH] update FSF address in COPYING 2005-09-10 10:06:29 -07:00
CREDITS Merge branch 'x86-microcode-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-12-12 15:23:02 -08:00
Kbuild scripts/gdb: provide linux constants 2016-05-23 17:04:14 -07:00
Kconfig kbuild: migrate all arch to the kconfig mainmenu upgrade 2010-09-19 22:54:11 -04:00
MAINTAINERS Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2016-12-14 13:31:29 -08:00
Makefile Linux 4.9 2016-12-11 11:17:54 -08:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.