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259065 |
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07-Dec-2013 |
gjb |
- Copy stable/10 (r259064) to releng/10.0 as part of the 10.0-RELEASE cycle. - Update __FreeBSD_version [1] - Set branch name to -RC1
[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so start releng/10.0 at '100' so the branch is started with a value ending in zero.
Approved by: re (implicit) Sponsored by: The FreeBSD Foundation |
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256281 |
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10-Oct-2013 |
gjb |
Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.
Approved by: re (implicit) Sponsored by: The FreeBSD Foundation
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216421 |
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13-Dec-2010 |
mckusick |
Tighten up some of the comments describing turnstiles and sleepqueues. No code changes.
Reviewed by: John Baldwin
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170295 |
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04-Jun-2007 |
jeff |
Commit 3/14 of sched_lock decomposition. - Add a per-turnstile spinlock to solve potential priority propagation deadlocks that are possible with thread_lock(). - The turnstile lock order is defined as the exact opposite of the lock order used with the sleep locks they represent. This allows us to walk in reverse order in priority_propagate and this is the only place we wish to multiply acquire turnstile locks. - Use the turnstile_chain lock to protect assigning mutexes to turnstiles. - Change the turnstile interface to pass back turnstile pointers to the consumers. This allows us to reduce some locking and makes it easier to cancel turnstile assignment while the turnstile chain lock is held.
Tested by: kris, current@ Tested on: i386, amd64, ULE, 4BSD, libthr, libkse, PREEMPTION, etc. Discussed with: kris, attilio, kmacy, jhb, julian, bde (small parts each)
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157845 |
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18-Apr-2006 |
jhb |
Update comments to mention that each turnstile contains two queues and to describe turnstile_disown() and turnstile_empty().
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157844 |
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18-Apr-2006 |
jhb |
- Bring back turnstile_empty() which can check to see if an individual queue on a turnstile is empty. - Add a turnstile_disown() function that allows a thread to give up ownership of a turnstile w/o waking up any waiters.
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154937 |
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27-Jan-2006 |
jhb |
- Add support for having both a shared and exclusive queue of threads in each turnstile. Also, allow for the owner thread pointer of a turnstile to be NULL. This is needed for the upcoming reader/writer lock implementation. - Add a new ddb command 'show turnstile' that will look up the turnstile associated with the given lock argument and display useful information like the list of threads blocked on each queue, etc. If there isn't an active turnstile for a lock at the specified address, then the function will see if there is an active turnstile at the specified address and display info about it if so. - Adjust the mutex code to handle the turnstile API changes.
Tested on: i386 (all), alpha, amd64, sparc64 (1 and 3)
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154480 |
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17-Jan-2006 |
jhb |
Garbage collect turnstile_empty() since it is unused.
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139825 |
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07-Jan-2005 |
imp |
/* -> /*- for license, minor formatting changes
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139453 |
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30-Dec-2004 |
jhb |
Rework the interface between priority propagation (lending) and the schedulers a bit to ensure more correct handling of priorities and fewer priority inversions: - Add two functions to the sched(9) API to handle priority lending: sched_lend_prio() and sched_unlend_prio(). The turnstile code uses these functions to ask the scheduler to lend a thread a set priority and to tell the scheduler when it thinks it is ok for a thread to stop borrowing priority. The unlend case is slightly complex in that the turnstile code tells the scheduler what the minimum priority of the thread needs to be to satisfy the requirements of any other threads blocked on locks owned by the thread in question. The scheduler then decides where the thread can go back to normal mode (if it's normal priority is high enough to satisfy the pending lock requests) or it it should continue to use the priority specified to the sched_unlend_prio() call. This involves adding a new per-thread flag TDF_BORROWING that replaces the ULE-only kse flag for priority elevation. - Schedulers now refuse to lower the priority of a thread that is currently borrowing another therad's priority. - If a scheduler changes the priority of a thread that is currently sitting on a turnstile, it will call a new function turnstile_adjust() to inform the turnstile code of the change. This function resorts the thread on the priority list of the turnstile if needed, and if the thread ends up at the head of the list (due to having the highest priority) and its priority was raised, then it will propagate that new priority to the owner of the lock it is blocked on.
Some additional fixes specific to the 4BSD scheduler include: - Common code for updating the priority of a thread when the user priority of its associated kse group has been consolidated in a new static function resetpriority_thread(). One change to this function is that it will now only adjust the priority of a thread if it already has a time sharing priority, thus preserving any boosts from a tsleep() until the thread returns to userland. Also, resetpriority() no longer calls maybe_resched() on each thread in the group. Instead, the code calling resetpriority() is responsible for calling resetpriority_thread() on any threads that need to be updated. - schedcpu() now uses resetpriority_thread() instead of just calling sched_prio() directly after it updates a kse group's user priority. - sched_clock() now uses resetpriority_thread() rather than writing directly to td_priority. - sched_nice() now updates all the priorities of the threads after the group priority has been adjusted.
Discussed with: bde Reviewed by: ups, jeffr Tested on: 4bsd, ule Tested on: i386, alpha, sparc64
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136445 |
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12-Oct-2004 |
jhb |
Refine the turnstile and sleep queue interfaces just a bit: - Add a new _lock() call to each API that locks the associated chain lock for a lock_object pointer or wait channel. The _lookup() functions now require that the chain lock be locked via _lock() when they are called. - Change sleepq_add(), turnstile_wait() and turnstile_claim() to lookup the associated queue structure internally via _lookup() rather than accepting a pointer from the caller. For turnstiles, this means that the actual lookup of the turnstile in the hash table is only done when the thread actually blocks rather than being done on each loop iteration in _mtx_lock_sleep(). For sleep queues, this means that sleepq_lookup() is no longer used outside of the sleep queue code except to implement an assertion in cv_destroy(). - Change sleepq_broadcast() and sleepq_signal() to require that the chain lock is already required. For condition variables, this lets the cv_broadcast() and cv_signal() functions lock the sleep queue chain lock while testing the waiters count. This means that the waiters count internal to condition variables is no longer protected by the interlock mutex and cv_broadcast() and cv_signal() now no longer require that the interlock be held when they are called. This lets consumers of condition variables drop the lock before waking other threads which can result in fewer context switches.
MFC after: 1 month
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127952 |
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06-Apr-2004 |
jhb |
Sort function prototypes.
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127951 |
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06-Apr-2004 |
jhb |
Rename turnstile_wakeup() to turnstile_broadcast() to make the naming more consistent with other APIs. sleepq and cv's use signal/broadcast, and msleep uses wakeup_one/wakeup. Prior to this turnstiles were using a signal/wakeup mixture.
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126317 |
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27-Feb-2004 |
jhb |
Clarify and tweak some comments.
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122516 |
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11-Nov-2003 |
jhb |
Oh dear, forgot this file in the turnstile commit. This header defines the turnstile API and includes several comments.
Reminded by: peter
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