[PATCHSET pm] freezer: fix various bugs and simplify implementation, take#2

[Tejun Heo]

Hello,

This is the second take of this patchset.  The first take[F] was
pulled into pm-next but got lost during the korg incident.  It's
rebased on top of the current linus/master and while at it I tried to
address issues which were raised after the patchset got pulled in.

* Setting of PF_NOFREEZE moved to after TASK_DEAD setting as suggested
  by Oleg.

* Bug in freezer_change_state() which incorrectly set the state
  directly to CGROUP_FROZEN instead of CGROUP_FREEZING fixed.

* "freezer: fix set_freezable[_with_signal]() race" patch splitted
  into two parts and resequenced to satisfy ordering dependency
  between fixes.

* Added missing Acked-by's and made other minor updates.

Patchset description follows.

The freezer code has developed a number of convolutions and bugs.
It's now using five per-task flags - TIF_FREEZE, PF_FREEZING,
PF_NOFREEZE, PF_FROZEN, PF_FREEZER_SKIP and PF_FREEZER_NOSIG, and at
the same time has quite a few race conditions.  PF_NOFREEZE
modifications can race against PM freezer, cgroup_freezer can race
against PM freezer, and so on.

This patchset tries to simplify the freezer implementation and fix the
various bugs.  It makes the synchronization more straight forward and
replaces TIF_FREEZE with directly checking freeze conditions which are
in effect, which makes the whole thing much saner.

This patchset removes TIF_FREEZE and PF_FREEZING.  Also,
PF_FREEZER_SKIP users are planned to move away from the flag and will
be removed.  It contains the following 17 patches.

 0001-freezer-fix-current-state-restoration-race-in-refrig.patch
 0002-freezer-don-t-unnecessarily-set-PF_NOFREEZE-explicit.patch
 0003-freezer-unexport-refrigerator-and-update-try_to_free.patch
 0004-freezer-implement-and-use-kthread_freezable_should_s.patch
 0005-freezer-rename-thaw_process-to-__thaw_task-and-simpl.patch
 0006-freezer-remove-racy-clear_freeze_flag-and-set-PF_NOF.patch
 0007-freezer-don-t-distinguish-nosig-tasks-on-thaw.patch
 0008-freezer-use-dedicated-lock-instead-of-task_lock-memo.patch
 0009-freezer-make-freezing-indicate-freeze-condition-in-e.patch
 0010-freezer-test-freezable-conditions-while-holding-free.patch
 0011-freezer-kill-PF_FREEZING.patch
 0012-freezer-clean-up-freeze_processes-failure-path.patch
 0013-cgroup_freezer-prepare-for-removal-of-TIF_FREEZE.patch
 0014-freezer-make-freezing-test-freeze-conditions-in-effe.patch
 0015-freezer-remove-now-unused-TIF_FREEZE.patch
 0016-freezer-remove-should_send_signal-and-update-frozen.patch
 0017-freezer-fix-set_freezable-_with_signal-race.patch

This patchset is on top of the current linus/master (839d881074 "Merge
branch 'i2c-for-linus' of ...") and also available in the following
git branch.

 git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc.git pm-freezer

At this point, this definitely is for the next merge window.  Diffstat
follows.

 Documentation/power/freezing-of-tasks.txt |   14 +-
 arch/alpha/include/asm/thread_info.h      |    2 
 arch/arm/include/asm/thread_info.h        |    2 
 arch/avr32/include/asm/thread_info.h      |    2 
 arch/blackfin/include/asm/thread_info.h   |    2 
 arch/cris/include/asm/thread_info.h       |    2 
 arch/frv/include/asm/thread_info.h        |    2 
 arch/h8300/include/asm/thread_info.h      |    2 
 arch/ia64/include/asm/thread_info.h       |    2 
 arch/m32r/include/asm/thread_info.h       |    2 
 arch/m68k/include/asm/thread_info.h       |    1 
 arch/microblaze/include/asm/thread_info.h |    2 
 arch/mips/include/asm/thread_info.h       |    2 
 arch/mn10300/include/asm/thread_info.h    |    2 
 arch/parisc/include/asm/thread_info.h     |    2 
 arch/powerpc/include/asm/thread_info.h    |    2 
 arch/s390/include/asm/thread_info.h       |    2 
 arch/sh/include/asm/thread_info.h         |    2 
 arch/sparc/include/asm/thread_info_32.h   |    2 
 arch/sparc/include/asm/thread_info_64.h   |    2 
 arch/um/include/asm/thread_info.h         |    2 
 arch/unicore32/include/asm/thread_info.h  |    2 
 arch/x86/include/asm/thread_info.h        |    2 
 arch/xtensa/include/asm/thread_info.h     |    2 
 drivers/bluetooth/btmrvl_main.c           |    2 
 drivers/mfd/twl4030-irq.c                 |    3 
 drivers/mfd/twl6030-irq.c                 |    2 
 drivers/net/irda/stir4200.c               |    2 
 drivers/platform/x86/thinkpad_acpi.c      |   15 --
 drivers/staging/rts_pstor/rtsx.c          |    2 
 fs/btrfs/async-thread.c                   |    2 
 fs/btrfs/disk-io.c                        |    8 -
 fs/ext4/super.c                           |    3 
 fs/fs-writeback.c                         |    4 
 fs/gfs2/log.c                             |    4 
 fs/gfs2/quota.c                           |    4 
 fs/jbd/journal.c                          |    2 
 fs/jbd2/journal.c                         |    2 
 fs/jfs/jfs_logmgr.c                       |    2 
 fs/jfs/jfs_txnmgr.c                       |    4 
 fs/nilfs2/segment.c                       |    2 
 fs/xfs/xfs_buf.c                          |    2 
 include/linux/freezer.h                   |   78 +++++-------
 include/linux/kthread.h                   |    1 
 include/linux/sched.h                     |    3 
 kernel/cgroup_freezer.c                   |   53 +++-----
 kernel/exit.c                             |    3 
 kernel/fork.c                             |    1 
 kernel/freezer.c                          |  182 +++++++++++++++++-------------
 kernel/kthread.c                          |   25 ++++
 kernel/power/hibernate.c                  |   15 --
 kernel/power/process.c                    |   67 +++--------
 kernel/power/user.c                       |    4 
 mm/backing-dev.c                          |    8 -
 54 files changed, 248 insertions(+), 316 deletions(-)

Thank you.

--
tejun

[F] http://thread.gmane.org/gmane.linux.kernel/1181594
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/