user/sven/linux.git/kernel/workqueue.c, branch v3.12.18

workqueue: ensure @task is valid across kthread_stop()

2014-03-05T16:13:50Z

commit 5bdfff96c69a4d5ab9c49e60abf9e070ecd2acbb upstream. When a kworker should die, the kworkre is notified through WORKER_DIE flag instead of kthread_should_stop(). This, IIRC, is primarily to keep the test synchronized inside worker_pool lock. WORKER_DIE is first set while holding pool->lock, the lock is dropped and kthread_stop() is called. Unfortunately, this means that there's a slight chance that the target kworker may see WORKER_DIE before kthread_stop() finishes and exits and frees the target task before or during kthread_stop(). Fix it by pinning the target task before setting WORKER_DIE and putting it after kthread_stop() is done. tj: Improved patch description and comment. Moved pinning above WORKER_DIE for better signify what it's protecting. Signed-off-by: Lai Jiangshan Signed-off-by: Tejun Heo Signed-off-by: Jiri Slaby

workqueue: fix ordered workqueues in NUMA setups

2013-12-04T19:05:55Z

commit 8a2b75384444488fc4f2cbb9f0921b6a0794838f upstream. An ordered workqueue implements execution ordering by using single pool_workqueue with max_active == 1. On a given pool_workqueue, work items are processed in FIFO order and limiting max_active to 1 enforces the queued work items to be processed one by one. Unfortunately, 4c16bd327c ("workqueue: implement NUMA affinity for unbound workqueues") accidentally broke this guarantee by applying NUMA affinity to ordered workqueues too. On NUMA setups, an ordered workqueue would end up with separate pool_workqueues for different nodes. Each pool_workqueue still limits max_active to 1 but multiple work items may be executed concurrently and out of order depending on which node they are queued to. Fix it by using dedicated ordered_wq_attrs[] when creating ordered workqueues. The new attrs match the unbound ones except that no_numa is always set thus forcing all NUMA nodes to share the default pool_workqueue. While at it, add sanity check in workqueue creation path which verifies that an ordered workqueues has only the default pool_workqueue. Signed-off-by: Tejun Heo Reported-by: Libin Cc: Lai Jiangshan Signed-off-by: Greg Kroah-Hartman

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial

2013-09-06T16:36:28Z

Pull trivial tree from Jiri Kosina: "The usual trivial updates all over the tree -- mostly typo fixes and documentation updates" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (52 commits) doc: Documentation/cputopology.txt fix typo treewide: Convert retrun typos to return Fix comment typo for init_cma_reserved_pageblock Documentation/trace: Correcting and extending tracepoint documentation mm/hotplug: fix a typo in Documentation/memory-hotplug.txt power: Documentation: Update s2ram link doc: fix a typo in Documentation/00-INDEX Documentation/printk-formats.txt: No casts needed for u64/s64 doc: Fix typo "is is" in Documentations treewide: Fix printks with 0x%# zram: doc fixes Documentation/kmemcheck: update kmemcheck documentation doc: documentation/hwspinlock.txt fix typo PM / Hibernate: add section for resume options doc: filesystems : Fix typo in Documentations/filesystems scsi/megaraid fixed several typos in comments ppc: init_32: Fix error typo "CONFIG_START_KERNEL" treewide: Add __GFP_NOWARN to k.alloc calls with v.alloc fallbacks page_isolation: Fix a comment typo in test_pages_isolated() doc: fix a typo about irq affinity ...

Merge branch 'for-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

2013-09-04T01:19:21Z

Pull workqueue updates from Tejun Heo: "Nothing interesting. All are doc / comment updates" * 'for-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: Correct/Drop references to gcwq in Documentation workqueue: Fix manage_workers() RETURNS description workqueue: Comment correction in file header workqueue: mark WQ_NON_REENTRANT deprecated

Merge tag 'driver-core-3.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2013-09-03T18:37:15Z

Pull driver core patches from Greg KH: "Here's the big driver core pull request for 3.12-rc1. Lots of tiny changes here fixing up the way sysfs attributes are created, to try to make drivers simpler, and fix a whole class race conditions with creations of device attributes after the device was announced to userspace. All the various pieces are acked by the different subsystem maintainers" * tag 'driver-core-3.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (119 commits) firmware loader: fix pending_fw_head list corruption drivers/base/memory.c: introduce help macro to_memory_block dynamic debug: line queries failing due to uninitialized local variable sysfs: sysfs_create_groups returns a value. debugfs: provide debugfs_create_x64() when disabled rbd: convert bus code to use bus_groups firmware: dcdbas: use binary attribute groups sysfs: add sysfs_create/remove_groups for when SYSFS is not enabled driver core: add #include to core files. HID: convert bus code to use dev_groups Input: serio: convert bus code to use drv_groups Input: gameport: convert bus code to use drv_groups driver core: firmware: use __ATTR_RW() driver core: core: use DEVICE_ATTR_RO driver core: bus: use DRIVER_ATTR_WO() driver core: create write-only attribute macros for devices and drivers sysfs: create __ATTR_WO() driver-core: platform: convert bus code to use dev_groups workqueue: convert bus code to use dev_groups MEI: convert bus code to use dev_groups ...

workqueue: cond_resched() after processing each work item

2013-08-29T13:19:28Z

If !PREEMPT, a kworker running work items back to back can hog CPU. This becomes dangerous when a self-requeueing work item which is waiting for something to happen races against stop_machine. Such self-requeueing work item would requeue itself indefinitely hogging the kworker and CPU it's running on while stop_machine would wait for that CPU to enter stop_machine while preventing anything else from happening on all other CPUs. The two would deadlock. Jamie Liu reports that this deadlock scenario exists around scsi_requeue_run_queue() and libata port multiplier support, where one port may exclude command processing from other ports. With the right timing, scsi_requeue_run_queue() can end up requeueing itself trying to execute an IO which is asked to be retried while another device has an exclusive access, which in turn can't make forward progress due to stop_machine. Fix it by invoking cond_resched() after executing each work item. Signed-off-by: Tejun Heo Reported-by: Jamie Liu References: http://thread.gmane.org/gmane.linux.kernel/1552567 Cc: stable@vger.kernel.org -- kernel/workqueue.c | 9 +++++++++ 1 file changed, 9 insertions(+)

workqueue: convert bus code to use dev_groups

2013-08-23T21:38:12Z

The dev_attrs field of struct bus_type is going away soon, dev_groups should be used instead. This converts the workqueue bus code to use the correct field. Acked-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

workqueue: Fix manage_workers() RETURNS description

2013-08-21T14:32:09Z

No functional change. The comment of function manage_workers() RETURNS description is obvious wrong, same as the CONTEXT. Fix it. Signed-off-by: Libin Signed-off-by: Tejun Heo

workqueue: Comment correction in file header

2013-08-21T14:32:09Z

No functional change. There are two worker pools for each cpu in current implementation (one for normal work items and the other for high priority ones). tj: Whitespace adjustments. Signed-off-by: Libin Signed-off-by: Tejun Heo

workqueue: fix some scripts/kernel-doc warnings

2013-08-20T10:57:25Z

When building the htmldocs (in verbose mode), scripts/kernel-doc reports the following type of warnings: Warning(kernel/workqueue.c:653): No description found for return value of 'get_work_pool' Fix them by: - Using "Return:" sections to introduce descriptions of return values - Adding some missing descriptions Signed-off-by: Yacine Belkadi Signed-off-by: Jiri Kosina