user/sven/linux.git/include/linux/freezer.h, branch v3.2.31

PM / Hibernate: Fix s2disk regression related to freezing workqueues

2012-02-13T19:16:55Z

commit 181e9bdef37bfcaa41f3ab6c948a2a0d60a268b5 upstream. Commit 2aede851ddf08666f68ffc17be446420e9d2a056 PM / Hibernate: Freeze kernel threads after preallocating memory introduced a mechanism by which kernel threads were frozen after the preallocation of hibernate image memory to avoid problems with frozen kernel threads not responding to memory freeing requests. However, it overlooked the s2disk code path in which the SNAPSHOT_CREATE_IMAGE ioctl was run directly after SNAPSHOT_FREE, which caused freeze_workqueues_begin() to BUG(), because it saw that worqueues had been already frozen. Although in principle this issue might be addressed by removing the relevant BUG_ON() from freeze_workqueues_begin(), that would reintroduce the very problem that commit 2aede851ddf08666f68ffc17be4 attempted to avoid into that particular code path. For this reason, to fix the issue at hand, introduce thaw_kernel_threads() and make the SNAPSHOT_FREE ioctl execute it. Special thanks to Srivatsa S. Bhat for detailed analysis of the problem. Reported-and-tested-by: Jiri Slaby Signed-off-by: Rafael J. Wysocki Acked-by: Srivatsa S. Bhat Signed-off-by: Greg Kroah-Hartman

PM / Freezer: Reimplement wait_event_freezekillable using freezer_do_not_count/freezer_count

2011-11-04T21:28:15Z

Commit 27920651fe "PM / Freezer: Make fake_signal_wake_up() wake TASK_KILLABLE tasks too" updated fake_signal_wake_up() used by freezer to wake up KILLABLE tasks. Sending unsolicited wakeups to tasks in killable sleep is dangerous as there are code paths which depend on tasks not waking up spuriously from KILLABLE sleep. For example. sys_read() or page can sleep in TASK_KILLABLE assuming that wait/down/whatever _killable can only fail if we can not return to the usermode. TASK_TRACED is another obvious example. The offending commit was to resolve freezer hang during system PM operations caused by KILLABLE sleeps in network filesystems. wait_event_freezekillable(), which depends on the spurious KILLABLE wakeup, was added by f06ac72e92 "cifs, freezer: add wait_event_freezekillable and have cifs use it" to be used to implement killable & freezable sleeps in network filesystems. To prepare for reverting of 27920651fe, this patch reimplements wait_event_freezekillable() using freezer_do_not_count/freezer_count() so that it doesn't depend on the spurious KILLABLE wakeup. This isn't very nice but should do for now. [tj: Refreshed patch to apply to linus/master and updated commit description on Rafael's request.] Signed-off-by: Oleg Nesterov Signed-off-by: Tejun Heo Signed-off-by: Rafael J. Wysocki

Merge branch '3.2-without-smb2' of git://git.samba.org/sfrench/cifs-2.6

2011-10-28T17:43:32Z

* '3.2-without-smb2' of git://git.samba.org/sfrench/cifs-2.6: (52 commits) Fix build break when freezer not configured Add definition for share encryption CIFS: Make cifs_push_locks send as many locks at once as possible CIFS: Send as many mandatory unlock ranges at once as possible CIFS: Implement caching mechanism for posix brlocks CIFS: Implement caching mechanism for mandatory brlocks CIFS: Fix DFS handling in cifs_get_file_info CIFS: Fix error handling in cifs_readv_complete [CIFS] Fixup trivial checkpatch warning [CIFS] Show nostrictsync and noperm mount options in /proc/mounts cifs, freezer: add wait_event_freezekillable and have cifs use it cifs: allow cifs_max_pending to be readable under /sys/module/cifs/parameters cifs: tune bdi.ra_pages in accordance with the rsize cifs: allow for larger rsize= options and change defaults cifs: convert cifs_readpages to use async reads cifs: add cifs_async_readv cifs: fix protocol definition for READ_RSP cifs: add a callback function to receive the rest of the frame cifs: break out 3rd receive phase into separate function cifs: find mid earlier in receive codepath ...

Fix build break when freezer not configured

2011-10-27T21:53:40Z

fs/cifs/transport.c: In function 'wait_for_response': fs/cifs/transport.c:328: error: implicit declaration of function 'wait_event_freezekillable' Caused by commit f06ac72e9291 ("cifs, freezer: add wait_event_freezekillable and have cifs use it"). In this config, CONFIG_FREEZER is not set. Reviewed-by: Shirish Pargaonkar CC: Jeff Layton Signed-off-by: Steve French

[CIFS] Fixup trivial checkpatch warning

2011-10-20T02:27:11Z

Signed-off-by: Steve French

cifs, freezer: add wait_event_freezekillable and have cifs use it

2011-10-19T19:30:40Z

CIFS currently uses wait_event_killable to put tasks to sleep while they await replies from the server. That function though does not allow the freezer to run. In many cases, the network interface may be going down anyway, in which case the reply will never come. The client then ends up blocking the computer from suspending. Fix this by adding a new wait_event_freezable variant -- wait_event_freezekillable. The idea is to combine the behavior of wait_event_killable and wait_event_freezable -- put the task to sleep and only allow it to be awoken by fatal signals, but also allow the freezer to do its job. Signed-off-by: Jeff Layton

PM / Hibernate: Freeze kernel threads after preallocating memory

2011-10-16T21:28:52Z

There is a problem with the current ordering of hibernate code which leads to deadlocks in some filesystems' memory shrinkers. Namely, some filesystems use freezable kernel threads that are inactive when the hibernate memory preallocation is carried out. Those same filesystems use memory shrinkers that may be triggered by the hibernate memory preallocation. If those memory shrinkers wait for the frozen kernel threads, the hibernate process deadlocks (this happens with XFS, for one example). Apparently, it is not technically viable to redesign the filesystems in question to avoid the situation described above, so the only possible solution of this issue is to defer the freezing of kernel threads until the hibernate memory preallocation is done, which is implemented by this change. Unfortunately, this requires the memory preallocation to be done before the "prepare" stage of device freeze, so after this change the only way drivers can allocate additional memory for their freeze routines in a clean way is to use PM notifiers. Reported-by: Christoph Signed-off-by: Rafael J. Wysocki

workqueue, freezer: unify spelling of 'freeze' + 'able' to 'freezable'

2011-02-16T16:48:59Z

There are two spellings in use for 'freeze' + 'able' - 'freezable' and 'freezeable'. The former is the more prominent one. The latter is mostly used by workqueue and in a few other odd places. Unify the spelling to 'freezable'. Signed-off-by: Tejun Heo Reported-by: Alan Stern Acked-by: "Rafael J. Wysocki" Acked-by: Greg Kroah-Hartman Acked-by: Dmitry Torokhov Cc: David Woodhouse Cc: Alex Dubov Cc: "David S. Miller" Cc: Steven Whitehouse

Freezer: Fix buggy resume test for tasks frozen with cgroup freezer

2010-03-26T22:51:44Z

When the cgroup freezer is used to freeze tasks we do not want to thaw those tasks during resume. Currently we test the cgroup freezer state of the resuming tasks to see if the cgroup is FROZEN. If so then we don't thaw the task. However, the FREEZING state also indicates that the task should remain frozen. This also avoids a problem pointed out by Oren Ladaan: the freezer state transition from FREEZING to FROZEN is updated lazily when userspace reads or writes the freezer.state file in the cgroup filesystem. This means that resume will thaw tasks in cgroups which should be in the FROZEN state if there is no read/write of the freezer.state file to trigger this transition before suspend. NOTE: Another "simple" solution would be to always update the cgroup freezer state during resume. However it's a bad choice for several reasons: Updating the cgroup freezer state is somewhat expensive because it requires walking all the tasks in the cgroup and checking if they are each frozen. Worse, this could easily make resume run in N^2 time where N is the number of tasks in the cgroup. Finally, updating the freezer state from this code path requires trickier locking because of the way locks must be ordered. Instead of updating the freezer state we rely on the fact that lazy updates only manage the transition from FREEZING to FROZEN. We know that a cgroup with the FREEZING state may actually be FROZEN so test for that state too. This makes sense in the resume path even for partially-frozen cgroups -- those that really are FREEZING but not FROZEN. Reported-by: Oren Ladaan Signed-off-by: Matt Helsley Cc: stable@kernel.org Signed-off-by: Rafael J. Wysocki

freezer_cg: use thaw_process() in unfreeze_cgroup()

2008-10-30T18:38:45Z

Don't duplicate the implementation of thaw_process(). [akpm@linux-foundation.org: make __thaw_process() static] Signed-off-by: Li Zefan Cc: Cedric Le Goater Acked-by: Matt Helsley Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds