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Tetsuo Handa b014bebab0 kernel/hung_task.c: Use continuously blocked time when reporting.
Since commit a2e5144538 ("kernel/hung_task.c: allow to set checking
interval separately from timeout") added hung_task_check_interval_secs,
setting a value different from hung_task_timeout_secs

  echo 0 > /proc/sys/kernel/hung_task_panic
  echo 120 > /proc/sys/kernel/hung_task_timeout_secs
  echo 5 > /proc/sys/kernel/hung_task_check_interval_secs

causes confusing output as if the task was blocked for
hung_task_timeout_secs seconds from the previous report.

  [  399.395930] INFO: task kswapd0:75 blocked for more than 120 seconds.
  [  405.027637] INFO: task kswapd0:75 blocked for more than 120 seconds.
  [  410.659725] INFO: task kswapd0:75 blocked for more than 120 seconds.
  [  416.292860] INFO: task kswapd0:75 blocked for more than 120 seconds.
  [  421.932305] INFO: task kswapd0:75 blocked for more than 120 seconds.

Although we could update t->last_switch_time after sched_show_task(t) if
we want to report only every 120 seconds, reporting every 5 seconds
might not be very bad for monitoring after a problematic situation has
started.  Thus, let's use continuously blocked time instead of updating
previously reported time.

  [  677.985011] INFO: task kswapd0:80 blocked for more than 122 seconds.
  [  693.856126] INFO: task kswapd0:80 blocked for more than 138 seconds.
  [  709.728075] INFO: task kswapd0:80 blocked for more than 154 seconds.
  [  725.600018] INFO: task kswapd0:80 blocked for more than 170 seconds.
  [  741.473133] INFO: task kswapd0:80 blocked for more than 186 seconds.

Link: http://lkml.kernel.org/r/1551175083-10669-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-07 18:31:59 -08:00
arch Driver core patches for 5.1-rc1 2019-03-06 14:52:48 -08:00
block for-linus-20190215 2019-02-15 09:12:28 -08:00
certs kbuild: remove redundant target cleaning on failure 2019-01-06 09:46:51 +09:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2019-03-05 09:09:55 -08:00
Documentation USB/PHY patches for 5.1-rc1 2019-03-06 16:48:27 -08:00
drivers USB/PHY patches for 5.1-rc1 2019-03-06 16:48:27 -08:00
fs Driver core patches for 5.1-rc1 2019-03-06 14:52:48 -08:00
include include/linux/types.h: use "unsigned int" instead of "unsigned" 2019-03-07 18:31:59 -08:00
init Merge branch 'akpm' (patches from Andrew) 2019-03-06 10:31:36 -08:00
ipc y2038: syscalls: rename y2038 compat syscalls 2019-02-07 00:13:27 +01:00
kernel kernel/hung_task.c: Use continuously blocked time when reporting. 2019-03-07 18:31:59 -08:00
lib Driver core patches for 5.1-rc1 2019-03-06 14:52:48 -08:00
LICENSES This is a fairly typical cycle for documentation. There's some welcome 2018-10-24 18:01:11 +01:00
mm mm,mremap: bail out earlier in mremap_to under map pressure 2019-03-05 21:07:21 -08:00
net Merge branch 'akpm' (patches from Andrew) 2019-03-06 10:31:36 -08:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2019-03-05 08:26:13 -08:00
scripts Char/Misc driver patches for 5.1-rc1 2019-03-06 14:18:59 -08:00
security get rid of legacy 'get_ds()' function 2019-03-04 10:50:14 -08:00
sound Char/Misc driver patches for 5.1-rc1 2019-03-06 14:18:59 -08:00
tools Staging/IIO patches for 5.1-rc1 2019-03-06 16:29:27 -08:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt ACPI updates for 5.1-rc1 2019-03-06 13:33:11 -08:00
.clang-format clang-format: Update .clang-format with the latest for_each macro list 2019-01-19 19:26:06 +01:00
.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 kbuild: Add support for DT binding schema checks 2018-12-13 09:41:32 -06:00
.mailmap .mailmap: Add Mathieu Othacehe 2019-02-21 11:41:19 +00:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Char/Misc driver patches for 5.1-rc1 2019-03-06 14:18:59 -08:00
Kbuild Merge branch 'locking/atomics' into locking/core, to pick up WIP commits 2019-02-11 14:27:05 +01:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS USB/PHY patches for 5.1-rc1 2019-03-06 16:48:27 -08:00
Makefile Driver core patches for 5.1-rc1 2019-03-06 14:52:48 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

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.