[PATCHSET] freezer: fix various bugs and simplify implementation

From: Tejun Heo
Date: Fri Aug 19 2011 - 10:21:16 EST


Hello,

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 16 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-make-exiting-tasks-properly-unfreezable.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-fix-set_freezable-_with_signal-race.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

This patchset is on top of the current linus#master (01b883358b "Merge
git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc") and
available in the following git branch.

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

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/linux-2.6/xfs_buf.c | 2
include/linux/freezer.h | 78 +++++--------
include/linux/kthread.h | 1
include/linux/sched.h | 3
kernel/cgroup_freezer.c | 51 +++-----
kernel/exit.c | 8 +
kernel/fork.c | 1
kernel/freezer.c | 179 +++++++++++++++++-------------
kernel/kthread.c | 25 ++++
kernel/power/hibernate.c | 15 --
kernel/power/process.c | 65 +++-------
kernel/power/user.c | 4
mm/backing-dev.c | 8 -
54 files changed, 247 insertions(+), 315 deletions(-)

Thanks.

--
tejun
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