linux/kernel/workqueue.c, branch v2.6.21-rc7

[PATCH] Add debugging feature /proc/timer_stat

2007-02-16T16:13:59Z

Add /proc/timer_stats support: debugging feature to profile timer expiration. Both the starting site, process/PID and the expiration function is captured. This allows the quick identification of timer event sources in a system. Sample output: # echo 1 > /proc/timer_stats # cat /proc/timer_stats Timer Stats Version: v0.1 Sample period: 4.010 s 24, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 11, 0 swapper sk_reset_timer (tcp_delack_timer) 6, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 17, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 4, 2050 pcscd do_nanosleep (hrtimer_wakeup) 5, 4179 sshd sk_reset_timer (tcp_write_timer) 4, 2248 yum-updatesd schedule_timeout (process_timeout) 18, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 3, 0 swapper sk_reset_timer (tcp_delack_timer) 1, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer) 2, 1 swapper e1000_up (e1000_watchdog) 1, 1 init schedule_timeout (process_timeout) 100 total events, 25.24 events/sec [ cleanups and hrtimers support from Thomas Gleixner ] [bunk@stusta.de: nr_entries can become static] Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner Cc: john stultz Cc: Roman Zippel Cc: Andi Kleen Signed-off-by: Adrian Bunk Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] Numerous fixes to kernel-doc info in source files.

2007-02-11T18:51:32Z

A variety of (mostly) innocuous fixes to the embedded kernel-doc content in source files, including: * make multi-line initial descriptions single line * denote some function names, constants and structs as such * change erroneous opening '/*' to '/**' in a few places * reword some text for clarity Signed-off-by: Robert P. J. Day Cc: "Randy.Dunlap" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] fix kernel-doc warnings in 2.6.20-rc1

2006-12-22T16:55:47Z

Fix kernel-doc warnings in 2.6.20-rc1. Signed-off-by: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] workqueue: fix schedule_on_each_cpu()

2006-12-21T08:20:01Z

fix the schedule_on_each_cpu() implementation: __queue_work() is now stricter, hence set the work-pending bit before passing in the new work. (found in the -rt tree, using Peter Zijlstra's files-lock scalability patchset) Signed-off-by: Ingo Molnar Signed-off-by: Linus Torvalds

Make workqueue bit operations work on "atomic_long_t"

2006-12-16T17:53:50Z

On architectures where the atomicity of the bit operations is handled by external means (ie a separate spinlock to protect concurrent accesses), just doing a direct assignment on the workqueue data field (as done by commit 4594bf159f1962cec3b727954b7c598b07e2e737) can cause the assignment to be lost due to lack of serialization with the bitops on the same word. So we need to serialize the assignment with the locks on those architectures (notably older ARM chips, PA-RISC and sparc32). So rather than using an "unsigned long", let's use "atomic_long_t", which already has a safe assignment operation (atomic_long_set()) on such architectures. This requires that the atomic operations use the same atomicity locks as the bit operations do, but that is largely the case anyway. Sparc32 will probably need fixing. Architectures (including modern ARM with LL/SC) that implement sane atomic operations for SMP won't see any of this matter. Cc: Russell King Cc: David Howells Cc: David Miller Cc: Matthew Wilcox Cc: Linux Arch Maintainers Cc: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] WorkStruct: Use direct assignment rather than cmpxchg()

2006-12-09T20:25:08Z

Use direct assignment rather than cmpxchg() as the latter is unavailable and unimplementable on some platforms and is actually unnecessary. The use of cmpxchg() was to guard against two possibilities, neither of which can actually occur: (1) The pending flag may have been unset or may be cleared. However, given where it's called, the pending flag is _always_ set. I don't think it can be unset whilst we're in set_wq_data(). Once the work is enqueued to be actually run, the only way off the queue is for it to be actually run. If it's a delayed work item, then the bit can't be cleared by the timer because we haven't started the timer yet. Also, the pending bit can't be cleared by cancelling the delayed work _until_ the work item has had its timer started. (2) The workqueue pointer might change. This can only happen in two cases: (a) The work item has just been queued to actually run, and so we're protected by the appropriate workqueue spinlock. (b) A delayed work item is being queued, and so the timer hasn't been started yet, and so no one else knows about the work item or can access it (the pending bit protects us). Besides, set_wq_data() _sets_ the workqueue pointer unconditionally, so it can be assigned instead. So, replacing the set_wq_data() with a straight assignment would be okay in most cases. The problem is where we end up tangling with test_and_set_bit() emulated using spinlocks, and even then it's not a problem _provided_ test_and_set_bit() doesn't attempt to modify the word if the bit was set. If that's a problem, then a bitops-proofed assignment will be required - equivalent to atomic_set() vs other atomic_xxx() ops. Signed-off-by: David Howells Signed-off-by: Linus Torvalds

Add "run_scheduled_work()" workqueue function

2006-12-07T17:28:19Z

This allows workqueue users to run just their own pending work, rather than wait for the whole workqueue to finish running. This solves the deadlock with networking libphy that was due to other workqueue entries possibly needing a lock that was held by the routine that wanted to flush its own work. It's not wonderful: if you absolutely need to synchronize with the work function having been executed, any user strictly speaking should have its own completion tracking logic, since when we run things explicitly by hand, the generic workqueue layer can no longer help us synchronize. Also, this is strictly only usable for work that has been scheduled without any delayed timers. You can not mix the new interface with schedule_delayed_work(). But it's better than what we had currently. Acked-by: Maciej W. Rozycki Signed-off-by: Linus Torvalds

[PATCH] hotplug CPU: clean up hotcpu_notifier() use

2006-12-07T16:39:39Z

There was lots of #ifdef noise in the kernel due to hotcpu_notifier(fn, prio) not correctly marking 'fn' as used in the !HOTPLUG_CPU case, and thus generating compiler warnings of unused symbols, hence forcing people to add #ifdefs. the compiler can skip truly unused functions just fine: text data bss dec hex filename 1624412 728710 3674856 6027978 5bfaca vmlinux.before 1624412 728710 3674856 6027978 5bfaca vmlinux.after [akpm@osdl.org: topology.c fix] Signed-off-by: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] debug: workqueue locking sanity

2006-12-07T16:39:36Z

Workqueue functions should not leak locks, assert so, printing the last function ran. Use macros in lockdep.h to avoid include dependency pains. [akpm@osdl.org: build fix] Signed-off-by: Peter Zijlstra Acked-by: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] Support for freezeable workqueues

2006-12-07T16:39:29Z

Make it possible to create a workqueue the worker thread of which will be frozen during suspend, along with other kernel threads. Signed-off-by: Rafael J. Wysocki Acked-by: Pavel Machek Cc: Nigel Cunningham Cc: David Chinner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds