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slow-work: kill it
slow-work doesn't have any user left. Kill it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: David Howells <dhowells@redhat.com>
This commit is contained in:
Tejun Heo
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6ecd7c2dd9
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181a51f6e0
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====================================
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SLOW WORK ITEM EXECUTION THREAD POOL
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====================================
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By: David Howells <dhowells@redhat.com>
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The slow work item execution thread pool is a pool of threads for performing
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things that take a relatively long time, such as making mkdir calls.
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Typically, when processing something, these items will spend a lot of time
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blocking a thread on I/O, thus making that thread unavailable for doing other
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work.
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The standard workqueue model is unsuitable for this class of work item as that
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limits the owner to a single thread or a single thread per CPU. For some
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tasks, however, more threads - or fewer - are required.
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There is just one pool per system. It contains no threads unless something
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wants to use it - and that something must register its interest first. When
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the pool is active, the number of threads it contains is dynamic, varying
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between a maximum and minimum setting, depending on the load.
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====================
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CLASSES OF WORK ITEM
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====================
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This pool support two classes of work items:
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(*) Slow work items.
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(*) Very slow work items.
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The former are expected to finish much quicker than the latter.
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An operation of the very slow class may do a batch combination of several
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lookups, mkdirs, and a create for instance.
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An operation of the ordinarily slow class may, for example, write stuff or
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expand files, provided the time taken to do so isn't too long.
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Operations of both types may sleep during execution, thus tying up the thread
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loaned to it.
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A further class of work item is available, based on the slow work item class:
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(*) Delayed slow work items.
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These are slow work items that have a timer to defer queueing of the item for
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a while.
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THREAD-TO-CLASS ALLOCATION
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--------------------------
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Not all the threads in the pool are available to work on very slow work items.
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The number will be between one and one fewer than the number of active threads.
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This is configurable (see the "Pool Configuration" section).
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All the threads are available to work on ordinarily slow work items, but a
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percentage of the threads will prefer to work on very slow work items.
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The configuration ensures that at least one thread will be available to work on
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very slow work items, and at least one thread will be available that won't work
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on very slow work items at all.
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=====================
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USING SLOW WORK ITEMS
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=====================
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Firstly, a module or subsystem wanting to make use of slow work items must
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register its interest:
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int ret = slow_work_register_user(struct module *module);
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This will return 0 if successful, or a -ve error upon failure. The module
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pointer should be the module interested in using this facility (almost
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certainly THIS_MODULE).
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Slow work items may then be set up by:
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(1) Declaring a slow_work struct type variable:
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#include <linux/slow-work.h>
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struct slow_work myitem;
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(2) Declaring the operations to be used for this item:
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struct slow_work_ops myitem_ops = {
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.get_ref = myitem_get_ref,
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.put_ref = myitem_put_ref,
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.execute = myitem_execute,
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};
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[*] For a description of the ops, see section "Item Operations".
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(3) Initialising the item:
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slow_work_init(&myitem, &myitem_ops);
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or:
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delayed_slow_work_init(&myitem, &myitem_ops);
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or:
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vslow_work_init(&myitem, &myitem_ops);
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depending on its class.
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A suitably set up work item can then be enqueued for processing:
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int ret = slow_work_enqueue(&myitem);
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This will return a -ve error if the thread pool is unable to gain a reference
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on the item, 0 otherwise, or (for delayed work):
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int ret = delayed_slow_work_enqueue(&myitem, my_jiffy_delay);
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The items are reference counted, so there ought to be no need for a flush
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operation. But as the reference counting is optional, means to cancel
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existing work items are also included:
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cancel_slow_work(&myitem);
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cancel_delayed_slow_work(&myitem);
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can be used to cancel pending work. The above cancel function waits for
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existing work to have been executed (or prevent execution of them, depending
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on timing).
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When all a module's slow work items have been processed, and the
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module has no further interest in the facility, it should unregister its
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interest:
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slow_work_unregister_user(struct module *module);
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The module pointer is used to wait for all outstanding work items for that
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module before completing the unregistration. This prevents the put_ref() code
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from being taken away before it completes. module should almost certainly be
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THIS_MODULE.
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================
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HELPER FUNCTIONS
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================
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The slow-work facility provides a function by which it can be determined
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whether or not an item is queued for later execution:
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bool queued = slow_work_is_queued(struct slow_work *work);
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If it returns false, then the item is not on the queue (it may be executing
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with a requeue pending). This can be used to work out whether an item on which
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another depends is on the queue, thus allowing a dependent item to be queued
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after it.
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If the above shows an item on which another depends not to be queued, then the
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owner of the dependent item might need to wait. However, to avoid locking up
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the threads unnecessarily be sleeping in them, it can make sense under some
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circumstances to return the work item to the queue, thus deferring it until
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some other items have had a chance to make use of the yielded thread.
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To yield a thread and defer an item, the work function should simply enqueue
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the work item again and return. However, this doesn't work if there's nothing
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actually on the queue, as the thread just vacated will jump straight back into
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the item's work function, thus busy waiting on a CPU.
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Instead, the item should use the thread to wait for the dependency to go away,
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but rather than using schedule() or schedule_timeout() to sleep, it should use
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the following function:
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bool requeue = slow_work_sleep_till_thread_needed(
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struct slow_work *work,
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signed long *_timeout);
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This will add a second wait and then sleep, such that it will be woken up if
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either something appears on the queue that could usefully make use of the
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thread - and behind which this item can be queued, or if the event the caller
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set up to wait for happens. True will be returned if something else appeared
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on the queue and this work function should perhaps return, of false if
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something else woke it up. The timeout is as for schedule_timeout().
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For example:
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wq = bit_waitqueue(&my_flags, MY_BIT);
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init_wait(&wait);
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requeue = false;
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do {
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prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
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if (!test_bit(MY_BIT, &my_flags))
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break;
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requeue = slow_work_sleep_till_thread_needed(&my_work,
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&timeout);
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} while (timeout > 0 && !requeue);
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finish_wait(wq, &wait);
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if (!test_bit(MY_BIT, &my_flags)
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goto do_my_thing;
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if (requeue)
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return; // to slow_work
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===============
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ITEM OPERATIONS
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===============
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Each work item requires a table of operations of type struct slow_work_ops.
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Only ->execute() is required; the getting and putting of a reference and the
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describing of an item are all optional.
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(*) Get a reference on an item:
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int (*get_ref)(struct slow_work *work);
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This allows the thread pool to attempt to pin an item by getting a
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reference on it. This function should return 0 if the reference was
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granted, or a -ve error otherwise. If an error is returned,
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slow_work_enqueue() will fail.
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The reference is held whilst the item is queued and whilst it is being
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executed. The item may then be requeued with the same reference held, or
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the reference will be released.
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(*) Release a reference on an item:
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void (*put_ref)(struct slow_work *work);
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This allows the thread pool to unpin an item by releasing the reference on
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it. The thread pool will not touch the item again once this has been
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called.
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(*) Execute an item:
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void (*execute)(struct slow_work *work);
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This should perform the work required of the item. It may sleep, it may
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perform disk I/O and it may wait for locks.
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(*) View an item through /proc:
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void (*desc)(struct slow_work *work, struct seq_file *m);
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If supplied, this should print to 'm' a small string describing the work
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the item is to do. This should be no more than about 40 characters, and
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shouldn't include a newline character.
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See the 'Viewing executing and queued items' section below.
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==================
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POOL CONFIGURATION
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==================
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The slow-work thread pool has a number of configurables:
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(*) /proc/sys/kernel/slow-work/min-threads
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The minimum number of threads that should be in the pool whilst it is in
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use. This may be anywhere between 2 and max-threads.
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(*) /proc/sys/kernel/slow-work/max-threads
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The maximum number of threads that should in the pool. This may be
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anywhere between min-threads and 255 or NR_CPUS * 2, whichever is greater.
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(*) /proc/sys/kernel/slow-work/vslow-percentage
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The percentage of active threads in the pool that may be used to execute
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very slow work items. This may be between 1 and 99. The resultant number
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is bounded to between 1 and one fewer than the number of active threads.
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This ensures there is always at least one thread that can process very
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slow work items, and always at least one thread that won't.
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==================================
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VIEWING EXECUTING AND QUEUED ITEMS
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==================================
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If CONFIG_SLOW_WORK_DEBUG is enabled, a debugfs file is made available:
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/sys/kernel/debug/slow_work/runqueue
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through which the list of work items being executed and the queues of items to
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be executed may be viewed. The owner of a work item is given the chance to
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add some information of its own.
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The contents look something like the following:
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THR PID ITEM ADDR FL MARK DESC
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=== ===== ================ == ===== ==========
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0 3005 ffff880023f52348 a 952ms FSC: OBJ17d3: LOOK
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1 3006 ffff880024e33668 2 160ms FSC: OBJ17e5 OP60d3b: Write1/Store fl=2
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2 3165 ffff8800296dd180 a 424ms FSC: OBJ17e4: LOOK
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3 4089 ffff8800262c8d78 a 212ms FSC: OBJ17ea: CRTN
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4 4090 ffff88002792bed8 2 388ms FSC: OBJ17e8 OP60d36: Write1/Store fl=2
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5 4092 ffff88002a0ef308 2 388ms FSC: OBJ17e7 OP60d2e: Write1/Store fl=2
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6 4094 ffff88002abaf4b8 2 132ms FSC: OBJ17e2 OP60d4e: Write1/Store fl=2
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7 4095 ffff88002bb188e0 a 388ms FSC: OBJ17e9: CRTN
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vsq - ffff880023d99668 1 308ms FSC: OBJ17e0 OP60f91: Write1/EnQ fl=2
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vsq - ffff8800295d1740 1 212ms FSC: OBJ16be OP4d4b6: Write1/EnQ fl=2
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vsq - ffff880025ba3308 1 160ms FSC: OBJ179a OP58dec: Write1/EnQ fl=2
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vsq - ffff880024ec83e0 1 160ms FSC: OBJ17ae OP599f2: Write1/EnQ fl=2
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vsq - ffff880026618e00 1 160ms FSC: OBJ17e6 OP60d33: Write1/EnQ fl=2
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vsq - ffff880025a2a4b8 1 132ms FSC: OBJ16a2 OP4d583: Write1/EnQ fl=2
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vsq - ffff880023cbe6d8 9 212ms FSC: OBJ17eb: LOOK
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vsq - ffff880024d37590 9 212ms FSC: OBJ17ec: LOOK
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vsq - ffff880027746cb0 9 212ms FSC: OBJ17ed: LOOK
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vsq - ffff880024d37ae8 9 212ms FSC: OBJ17ee: LOOK
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vsq - ffff880024d37cb0 9 212ms FSC: OBJ17ef: LOOK
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vsq - ffff880025036550 9 212ms FSC: OBJ17f0: LOOK
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vsq - ffff8800250368e0 9 212ms FSC: OBJ17f1: LOOK
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vsq - ffff880025036aa8 9 212ms FSC: OBJ17f2: LOOK
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In the 'THR' column, executing items show the thread they're occupying and
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queued threads indicate which queue they're on. 'PID' shows the process ID of
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a slow-work thread that's executing something. 'FL' shows the work item flags.
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'MARK' indicates how long since an item was queued or began executing. Lastly,
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the 'DESC' column permits the owner of an item to give some information.
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@ -1,163 +0,0 @@
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/* Worker thread pool for slow items, such as filesystem lookups or mkdirs
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*
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* Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*
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* See Documentation/slow-work.txt
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*/
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#ifndef _LINUX_SLOW_WORK_H
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#define _LINUX_SLOW_WORK_H
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#ifdef CONFIG_SLOW_WORK
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#include <linux/sysctl.h>
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#include <linux/timer.h>
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struct slow_work;
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#ifdef CONFIG_SLOW_WORK_DEBUG
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struct seq_file;
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#endif
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/*
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* The operations used to support slow work items
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*/
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struct slow_work_ops {
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/* owner */
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struct module *owner;
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/* get a ref on a work item
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* - return 0 if successful, -ve if not
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*/
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int (*get_ref)(struct slow_work *work);
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/* discard a ref to a work item */
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void (*put_ref)(struct slow_work *work);
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/* execute a work item */
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void (*execute)(struct slow_work *work);
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#ifdef CONFIG_SLOW_WORK_DEBUG
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/* describe a work item for debugfs */
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void (*desc)(struct slow_work *work, struct seq_file *m);
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#endif
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};
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/*
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* A slow work item
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* - A reference is held on the parent object by the thread pool when it is
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* queued
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*/
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||||||
struct slow_work {
|
|
||||||
struct module *owner; /* the owning module */
|
|
||||||
unsigned long flags;
|
|
||||||
#define SLOW_WORK_PENDING 0 /* item pending (further) execution */
|
|
||||||
#define SLOW_WORK_EXECUTING 1 /* item currently executing */
|
|
||||||
#define SLOW_WORK_ENQ_DEFERRED 2 /* item enqueue deferred */
|
|
||||||
#define SLOW_WORK_VERY_SLOW 3 /* item is very slow */
|
|
||||||
#define SLOW_WORK_CANCELLING 4 /* item is being cancelled, don't enqueue */
|
|
||||||
#define SLOW_WORK_DELAYED 5 /* item is struct delayed_slow_work with active timer */
|
|
||||||
const struct slow_work_ops *ops; /* operations table for this item */
|
|
||||||
struct list_head link; /* link in queue */
|
|
||||||
#ifdef CONFIG_SLOW_WORK_DEBUG
|
|
||||||
struct timespec mark; /* jiffies at which queued or exec begun */
|
|
||||||
#endif
|
|
||||||
};
|
|
||||||
|
|
||||||
struct delayed_slow_work {
|
|
||||||
struct slow_work work;
|
|
||||||
struct timer_list timer;
|
|
||||||
};
|
|
||||||
|
|
||||||
/**
|
|
||||||
* slow_work_init - Initialise a slow work item
|
|
||||||
* @work: The work item to initialise
|
|
||||||
* @ops: The operations to use to handle the slow work item
|
|
||||||
*
|
|
||||||
* Initialise a slow work item.
|
|
||||||
*/
|
|
||||||
static inline void slow_work_init(struct slow_work *work,
|
|
||||||
const struct slow_work_ops *ops)
|
|
||||||
{
|
|
||||||
work->flags = 0;
|
|
||||||
work->ops = ops;
|
|
||||||
INIT_LIST_HEAD(&work->link);
|
|
||||||
}
|
|
||||||
|
|
||||||
/**
|
|
||||||
* slow_work_init - Initialise a delayed slow work item
|
|
||||||
* @work: The work item to initialise
|
|
||||||
* @ops: The operations to use to handle the slow work item
|
|
||||||
*
|
|
||||||
* Initialise a delayed slow work item.
|
|
||||||
*/
|
|
||||||
static inline void delayed_slow_work_init(struct delayed_slow_work *dwork,
|
|
||||||
const struct slow_work_ops *ops)
|
|
||||||
{
|
|
||||||
init_timer(&dwork->timer);
|
|
||||||
slow_work_init(&dwork->work, ops);
|
|
||||||
}
|
|
||||||
|
|
||||||
/**
|
|
||||||
* vslow_work_init - Initialise a very slow work item
|
|
||||||
* @work: The work item to initialise
|
|
||||||
* @ops: The operations to use to handle the slow work item
|
|
||||||
*
|
|
||||||
* Initialise a very slow work item. This item will be restricted such that
|
|
||||||
* only a certain number of the pool threads will be able to execute items of
|
|
||||||
* this type.
|
|
||||||
*/
|
|
||||||
static inline void vslow_work_init(struct slow_work *work,
|
|
||||||
const struct slow_work_ops *ops)
|
|
||||||
{
|
|
||||||
work->flags = 1 << SLOW_WORK_VERY_SLOW;
|
|
||||||
work->ops = ops;
|
|
||||||
INIT_LIST_HEAD(&work->link);
|
|
||||||
}
|
|
||||||
|
|
||||||
/**
|
|
||||||
* slow_work_is_queued - Determine if a slow work item is on the work queue
|
|
||||||
* work: The work item to test
|
|
||||||
*
|
|
||||||
* Determine if the specified slow-work item is on the work queue. This
|
|
||||||
* returns true if it is actually on the queue.
|
|
||||||
*
|
|
||||||
* If the item is executing and has been marked for requeue when execution
|
|
||||||
* finishes, then false will be returned.
|
|
||||||
*
|
|
||||||
* Anyone wishing to wait for completion of execution can wait on the
|
|
||||||
* SLOW_WORK_EXECUTING bit.
|
|
||||||
*/
|
|
||||||
static inline bool slow_work_is_queued(struct slow_work *work)
|
|
||||||
{
|
|
||||||
unsigned long flags = work->flags;
|
|
||||||
return flags & SLOW_WORK_PENDING && !(flags & SLOW_WORK_EXECUTING);
|
|
||||||
}
|
|
||||||
|
|
||||||
extern int slow_work_enqueue(struct slow_work *work);
|
|
||||||
extern void slow_work_cancel(struct slow_work *work);
|
|
||||||
extern int slow_work_register_user(struct module *owner);
|
|
||||||
extern void slow_work_unregister_user(struct module *owner);
|
|
||||||
|
|
||||||
extern int delayed_slow_work_enqueue(struct delayed_slow_work *dwork,
|
|
||||||
unsigned long delay);
|
|
||||||
|
|
||||||
static inline void delayed_slow_work_cancel(struct delayed_slow_work *dwork)
|
|
||||||
{
|
|
||||||
slow_work_cancel(&dwork->work);
|
|
||||||
}
|
|
||||||
|
|
||||||
extern bool slow_work_sleep_till_thread_needed(struct slow_work *work,
|
|
||||||
signed long *_timeout);
|
|
||||||
|
|
||||||
#ifdef CONFIG_SYSCTL
|
|
||||||
extern ctl_table slow_work_sysctls[];
|
|
||||||
#endif
|
|
||||||
|
|
||||||
#endif /* CONFIG_SLOW_WORK */
|
|
||||||
#endif /* _LINUX_SLOW_WORK_H */
|
|
||||||
24
init/Kconfig
24
init/Kconfig
@ -1143,30 +1143,6 @@ config TRACEPOINTS
|
|||||||
|
|
||||||
source "arch/Kconfig"
|
source "arch/Kconfig"
|
||||||
|
|
||||||
config SLOW_WORK
|
|
||||||
default n
|
|
||||||
bool
|
|
||||||
help
|
|
||||||
The slow work thread pool provides a number of dynamically allocated
|
|
||||||
threads that can be used by the kernel to perform operations that
|
|
||||||
take a relatively long time.
|
|
||||||
|
|
||||||
An example of this would be CacheFiles doing a path lookup followed
|
|
||||||
by a series of mkdirs and a create call, all of which have to touch
|
|
||||||
disk.
|
|
||||||
|
|
||||||
See Documentation/slow-work.txt.
|
|
||||||
|
|
||||||
config SLOW_WORK_DEBUG
|
|
||||||
bool "Slow work debugging through debugfs"
|
|
||||||
default n
|
|
||||||
depends on SLOW_WORK && DEBUG_FS
|
|
||||||
help
|
|
||||||
Display the contents of the slow work run queue through debugfs,
|
|
||||||
including items currently executing.
|
|
||||||
|
|
||||||
See Documentation/slow-work.txt.
|
|
||||||
|
|
||||||
endmenu # General setup
|
endmenu # General setup
|
||||||
|
|
||||||
config HAVE_GENERIC_DMA_COHERENT
|
config HAVE_GENERIC_DMA_COHERENT
|
||||||
|
|||||||
@ -99,8 +99,6 @@ obj-$(CONFIG_TRACING) += trace/
|
|||||||
obj-$(CONFIG_X86_DS) += trace/
|
obj-$(CONFIG_X86_DS) += trace/
|
||||||
obj-$(CONFIG_RING_BUFFER) += trace/
|
obj-$(CONFIG_RING_BUFFER) += trace/
|
||||||
obj-$(CONFIG_SMP) += sched_cpupri.o
|
obj-$(CONFIG_SMP) += sched_cpupri.o
|
||||||
obj-$(CONFIG_SLOW_WORK) += slow-work.o
|
|
||||||
obj-$(CONFIG_SLOW_WORK_DEBUG) += slow-work-debugfs.o
|
|
||||||
obj-$(CONFIG_PERF_EVENTS) += perf_event.o
|
obj-$(CONFIG_PERF_EVENTS) += perf_event.o
|
||||||
obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
|
obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
|
||||||
obj-$(CONFIG_USER_RETURN_NOTIFIER) += user-return-notifier.o
|
obj-$(CONFIG_USER_RETURN_NOTIFIER) += user-return-notifier.o
|
||||||
|
|||||||
@ -1,227 +0,0 @@
|
|||||||
/* Slow work debugging
|
|
||||||
*
|
|
||||||
* Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
|
|
||||||
* Written by David Howells (dhowells@redhat.com)
|
|
||||||
*
|
|
||||||
* This program is free software; you can redistribute it and/or
|
|
||||||
* modify it under the terms of the GNU General Public Licence
|
|
||||||
* as published by the Free Software Foundation; either version
|
|
||||||
* 2 of the Licence, or (at your option) any later version.
|
|
||||||
*/
|
|
||||||
|
|
||||||
#include <linux/module.h>
|
|
||||||
#include <linux/slow-work.h>
|
|
||||||
#include <linux/fs.h>
|
|
||||||
#include <linux/time.h>
|
|
||||||
#include <linux/seq_file.h>
|
|
||||||
#include "slow-work.h"
|
|
||||||
|
|
||||||
#define ITERATOR_SHIFT (BITS_PER_LONG - 4)
|
|
||||||
#define ITERATOR_SELECTOR (0xfUL << ITERATOR_SHIFT)
|
|
||||||
#define ITERATOR_COUNTER (~ITERATOR_SELECTOR)
|
|
||||||
|
|
||||||
void slow_work_new_thread_desc(struct slow_work *work, struct seq_file *m)
|
|
||||||
{
|
|
||||||
seq_puts(m, "Slow-work: New thread");
|
|
||||||
}
|
|
||||||
|
|
||||||
/*
|
|
||||||
* Render the time mark field on a work item into a 5-char time with units plus
|
|
||||||
* a space
|
|
||||||
*/
|
|
||||||
static void slow_work_print_mark(struct seq_file *m, struct slow_work *work)
|
|
||||||
{
|
|
||||||
struct timespec now, diff;
|
|
||||||
|
|
||||||
now = CURRENT_TIME;
|
|
||||||
diff = timespec_sub(now, work->mark);
|
|
||||||
|
|
||||||
if (diff.tv_sec < 0)
|
|
||||||
seq_puts(m, " -ve ");
|
|
||||||
else if (diff.tv_sec == 0 && diff.tv_nsec < 1000)
|
|
||||||
seq_printf(m, "%3luns ", diff.tv_nsec);
|
|
||||||
else if (diff.tv_sec == 0 && diff.tv_nsec < 1000000)
|
|
||||||
seq_printf(m, "%3luus ", diff.tv_nsec / 1000);
|
|
||||||
else if (diff.tv_sec == 0 && diff.tv_nsec < 1000000000)
|
|
||||||
seq_printf(m, "%3lums ", diff.tv_nsec / 1000000);
|
|
||||||
else if (diff.tv_sec <= 1)
|
|
||||||
seq_puts(m, " 1s ");
|
|
||||||
else if (diff.tv_sec < 60)
|
|
||||||
seq_printf(m, "%4lus ", diff.tv_sec);
|
|
||||||
else if (diff.tv_sec < 60 * 60)
|
|
||||||
seq_printf(m, "%4lum ", diff.tv_sec / 60);
|
|
||||||
else if (diff.tv_sec < 60 * 60 * 24)
|
|
||||||
seq_printf(m, "%4luh ", diff.tv_sec / 3600);
|
|
||||||
else
|
|
||||||
seq_puts(m, "exces ");
|
|
||||||
}
|
|
||||||
|
|
||||||
/*
|
|
||||||
* Describe a slow work item for debugfs
|
|
||||||
*/
|
|
||||||
static int slow_work_runqueue_show(struct seq_file *m, void *v)
|
|
||||||
{
|
|
||||||
struct slow_work *work;
|
|
||||||
struct list_head *p = v;
|
|
||||||
unsigned long id;
|
|
||||||
|
|
||||||
switch ((unsigned long) v) {
|
|
||||||
case 1:
|
|
||||||
seq_puts(m, "THR PID ITEM ADDR FL MARK DESC\n");
|
|
||||||
return 0;
|
|
||||||
case 2:
|
|
||||||
seq_puts(m, "=== ===== ================ == ===== ==========\n");
|
|
||||||
return 0;
|
|
||||||
|
|
||||||
case 3 ... 3 + SLOW_WORK_THREAD_LIMIT - 1:
|
|
||||||
id = (unsigned long) v - 3;
|
|
||||||
|
|
||||||
read_lock(&slow_work_execs_lock);
|
|
||||||
work = slow_work_execs[id];
|
|
||||||
if (work) {
|
|
||||||
smp_read_barrier_depends();
|
|
||||||
|
|
||||||
seq_printf(m, "%3lu %5d %16p %2lx ",
|
|
||||||
id, slow_work_pids[id], work, work->flags);
|
|
||||||
slow_work_print_mark(m, work);
|
|
||||||
|
|
||||||
if (work->ops->desc)
|
|
||||||
work->ops->desc(work, m);
|
|
||||||
seq_putc(m, '\n');
|
|
||||||
}
|
|
||||||
read_unlock(&slow_work_execs_lock);
|
|
||||||
return 0;
|
|
||||||
|
|
||||||
default:
|
|
||||||
work = list_entry(p, struct slow_work, link);
|
|
||||||
seq_printf(m, "%3s - %16p %2lx ",
|
|
||||||
work->flags & SLOW_WORK_VERY_SLOW ? "vsq" : "sq",
|
|
||||||
work, work->flags);
|
|
||||||
slow_work_print_mark(m, work);
|
|
||||||
|
|
||||||
if (work->ops->desc)
|
|
||||||
work->ops->desc(work, m);
|
|
||||||
seq_putc(m, '\n');
|
|
||||||
return 0;
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
/*
|
|
||||||
* map the iterator to a work item
|
|
||||||
*/
|
|
||||||
static void *slow_work_runqueue_index(struct seq_file *m, loff_t *_pos)
|
|
||||||
{
|
|
||||||
struct list_head *p;
|
|
||||||
unsigned long count, id;
|
|
||||||
|
|
||||||
switch (*_pos >> ITERATOR_SHIFT) {
|
|
||||||
case 0x0:
|
|
||||||
if (*_pos == 0)
|
|
||||||
*_pos = 1;
|
|
||||||
if (*_pos < 3)
|
|
||||||
return (void *)(unsigned long) *_pos;
|
|
||||||
if (*_pos < 3 + SLOW_WORK_THREAD_LIMIT)
|
|
||||||
for (id = *_pos - 3;
|
|
||||||
id < SLOW_WORK_THREAD_LIMIT;
|
|
||||||
id++, (*_pos)++)
|
|
||||||
if (slow_work_execs[id])
|
|
||||||
return (void *)(unsigned long) *_pos;
|
|
||||||
*_pos = 0x1UL << ITERATOR_SHIFT;
|
|
||||||
|
|
||||||
case 0x1:
|
|
||||||
count = *_pos & ITERATOR_COUNTER;
|
|
||||||
list_for_each(p, &slow_work_queue) {
|
|
||||||
if (count == 0)
|
|
||||||
return p;
|
|
||||||
count--;
|
|
||||||
}
|
|
||||||
*_pos = 0x2UL << ITERATOR_SHIFT;
|
|
||||||
|
|
||||||
case 0x2:
|
|
||||||
count = *_pos & ITERATOR_COUNTER;
|
|
||||||
list_for_each(p, &vslow_work_queue) {
|
|
||||||
if (count == 0)
|
|
||||||
return p;
|
|
||||||
count--;
|
|
||||||
}
|
|
||||||
*_pos = 0x3UL << ITERATOR_SHIFT;
|
|
||||||
|
|
||||||
default:
|
|
||||||
return NULL;
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
/*
|
|
||||||
* set up the iterator to start reading from the first line
|
|
||||||
*/
|
|
||||||
static void *slow_work_runqueue_start(struct seq_file *m, loff_t *_pos)
|
|
||||||
{
|
|
||||||
spin_lock_irq(&slow_work_queue_lock);
|
|
||||||
return slow_work_runqueue_index(m, _pos);
|
|
||||||
}
|
|
||||||
|
|
||||||
/*
|
|
||||||
* move to the next line
|
|
||||||
*/
|
|
||||||
static void *slow_work_runqueue_next(struct seq_file *m, void *v, loff_t *_pos)
|
|
||||||
{
|
|
||||||
struct list_head *p = v;
|
|
||||||
unsigned long selector = *_pos >> ITERATOR_SHIFT;
|
|
||||||
|
|
||||||
(*_pos)++;
|
|
||||||
switch (selector) {
|
|
||||||
case 0x0:
|
|
||||||
return slow_work_runqueue_index(m, _pos);
|
|
||||||
|
|
||||||
case 0x1:
|
|
||||||
if (*_pos >> ITERATOR_SHIFT == 0x1) {
|
|
||||||
p = p->next;
|
|
||||||
if (p != &slow_work_queue)
|
|
||||||
return p;
|
|
||||||
}
|
|
||||||
*_pos = 0x2UL << ITERATOR_SHIFT;
|
|
||||||
p = &vslow_work_queue;
|
|
||||||
|
|
||||||
case 0x2:
|
|
||||||
if (*_pos >> ITERATOR_SHIFT == 0x2) {
|
|
||||||
p = p->next;
|
|
||||||
if (p != &vslow_work_queue)
|
|
||||||
return p;
|
|
||||||
}
|
|
||||||
*_pos = 0x3UL << ITERATOR_SHIFT;
|
|
||||||
|
|
||||||
default:
|
|
||||||
return NULL;
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
/*
|
|
||||||
* clean up after reading
|
|
||||||
*/
|
|
||||||
static void slow_work_runqueue_stop(struct seq_file *m, void *v)
|
|
||||||
{
|
|
||||||
spin_unlock_irq(&slow_work_queue_lock);
|
|
||||||
}
|
|
||||||
|
|
||||||
static const struct seq_operations slow_work_runqueue_ops = {
|
|
||||||
.start = slow_work_runqueue_start,
|
|
||||||
.stop = slow_work_runqueue_stop,
|
|
||||||
.next = slow_work_runqueue_next,
|
|
||||||
.show = slow_work_runqueue_show,
|
|
||||||
};
|
|
||||||
|
|
||||||
/*
|
|
||||||
* open "/sys/kernel/debug/slow_work/runqueue" to list queue contents
|
|
||||||
*/
|
|
||||||
static int slow_work_runqueue_open(struct inode *inode, struct file *file)
|
|
||||||
{
|
|
||||||
return seq_open(file, &slow_work_runqueue_ops);
|
|
||||||
}
|
|
||||||
|
|
||||||
const struct file_operations slow_work_runqueue_fops = {
|
|
||||||
.owner = THIS_MODULE,
|
|
||||||
.open = slow_work_runqueue_open,
|
|
||||||
.read = seq_read,
|
|
||||||
.llseek = seq_lseek,
|
|
||||||
.release = seq_release,
|
|
||||||
};
|
|
||||||
1068
kernel/slow-work.c
1068
kernel/slow-work.c
File diff suppressed because it is too large
Load Diff
@ -1,72 +0,0 @@
|
|||||||
/* Slow work private definitions
|
|
||||||
*
|
|
||||||
* Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
|
|
||||||
* Written by David Howells (dhowells@redhat.com)
|
|
||||||
*
|
|
||||||
* This program is free software; you can redistribute it and/or
|
|
||||||
* modify it under the terms of the GNU General Public Licence
|
|
||||||
* as published by the Free Software Foundation; either version
|
|
||||||
* 2 of the Licence, or (at your option) any later version.
|
|
||||||
*/
|
|
||||||
|
|
||||||
#define SLOW_WORK_CULL_TIMEOUT (5 * HZ) /* cull threads 5s after running out of
|
|
||||||
* things to do */
|
|
||||||
#define SLOW_WORK_OOM_TIMEOUT (5 * HZ) /* can't start new threads for 5s after
|
|
||||||
* OOM */
|
|
||||||
|
|
||||||
#define SLOW_WORK_THREAD_LIMIT 255 /* abs maximum number of slow-work threads */
|
|
||||||
|
|
||||||
/*
|
|
||||||
* slow-work.c
|
|
||||||
*/
|
|
||||||
#ifdef CONFIG_SLOW_WORK_DEBUG
|
|
||||||
extern struct slow_work *slow_work_execs[];
|
|
||||||
extern pid_t slow_work_pids[];
|
|
||||||
extern rwlock_t slow_work_execs_lock;
|
|
||||||
#endif
|
|
||||||
|
|
||||||
extern struct list_head slow_work_queue;
|
|
||||||
extern struct list_head vslow_work_queue;
|
|
||||||
extern spinlock_t slow_work_queue_lock;
|
|
||||||
|
|
||||||
/*
|
|
||||||
* slow-work-debugfs.c
|
|
||||||
*/
|
|
||||||
#ifdef CONFIG_SLOW_WORK_DEBUG
|
|
||||||
extern const struct file_operations slow_work_runqueue_fops;
|
|
||||||
|
|
||||||
extern void slow_work_new_thread_desc(struct slow_work *, struct seq_file *);
|
|
||||||
#endif
|
|
||||||
|
|
||||||
/*
|
|
||||||
* Helper functions
|
|
||||||
*/
|
|
||||||
static inline void slow_work_set_thread_pid(int id, pid_t pid)
|
|
||||||
{
|
|
||||||
#ifdef CONFIG_SLOW_WORK_DEBUG
|
|
||||||
slow_work_pids[id] = pid;
|
|
||||||
#endif
|
|
||||||
}
|
|
||||||
|
|
||||||
static inline void slow_work_mark_time(struct slow_work *work)
|
|
||||||
{
|
|
||||||
#ifdef CONFIG_SLOW_WORK_DEBUG
|
|
||||||
work->mark = CURRENT_TIME;
|
|
||||||
#endif
|
|
||||||
}
|
|
||||||
|
|
||||||
static inline void slow_work_begin_exec(int id, struct slow_work *work)
|
|
||||||
{
|
|
||||||
#ifdef CONFIG_SLOW_WORK_DEBUG
|
|
||||||
slow_work_execs[id] = work;
|
|
||||||
#endif
|
|
||||||
}
|
|
||||||
|
|
||||||
static inline void slow_work_end_exec(int id, struct slow_work *work)
|
|
||||||
{
|
|
||||||
#ifdef CONFIG_SLOW_WORK_DEBUG
|
|
||||||
write_lock(&slow_work_execs_lock);
|
|
||||||
slow_work_execs[id] = NULL;
|
|
||||||
write_unlock(&slow_work_execs_lock);
|
|
||||||
#endif
|
|
||||||
}
|
|
||||||
@ -50,7 +50,6 @@
|
|||||||
#include <linux/acpi.h>
|
#include <linux/acpi.h>
|
||||||
#include <linux/reboot.h>
|
#include <linux/reboot.h>
|
||||||
#include <linux/ftrace.h>
|
#include <linux/ftrace.h>
|
||||||
#include <linux/slow-work.h>
|
|
||||||
#include <linux/perf_event.h>
|
#include <linux/perf_event.h>
|
||||||
#include <linux/kprobes.h>
|
#include <linux/kprobes.h>
|
||||||
#include <linux/pipe_fs_i.h>
|
#include <linux/pipe_fs_i.h>
|
||||||
@ -906,13 +905,6 @@ static struct ctl_table kern_table[] = {
|
|||||||
.proc_handler = proc_dointvec,
|
.proc_handler = proc_dointvec,
|
||||||
},
|
},
|
||||||
#endif
|
#endif
|
||||||
#ifdef CONFIG_SLOW_WORK
|
|
||||||
{
|
|
||||||
.procname = "slow-work",
|
|
||||||
.mode = 0555,
|
|
||||||
.child = slow_work_sysctls,
|
|
||||||
},
|
|
||||||
#endif
|
|
||||||
#ifdef CONFIG_PERF_EVENTS
|
#ifdef CONFIG_PERF_EVENTS
|
||||||
{
|
{
|
||||||
.procname = "perf_event_paranoid",
|
.procname = "perf_event_paranoid",
|
||||||
|
|||||||
Loading…
Reference in New Issue
Block a user