user/sven/linux.git/include/linux/init_task.h, branch v3.18.108

rcu: Remove local_irq_disable() in rcu_preempt_note_context_switch()

2014-09-07T23:27:34Z

The rcu_preempt_note_context_switch() function is on a scheduling fast path, so it would be good to avoid disabling irqs. The reason that irqs are disabled is to synchronize process-level and irq-handler access to the task_struct ->rcu_read_unlock_special bitmask. This commit therefore makes ->rcu_read_unlock_special instead be a union of bools with a short allowing single-access checks in RCU's __rcu_read_unlock(). This results in the process-level and irq-handler accesses being simple loads and stores, so that irqs need no longer be disabled. This commit therefore removes the irq disabling from rcu_preempt_note_context_switch(). Reported-by: Peter Zijlstra Signed-off-by: Paul E. McKenney

rcu: Make TASKS_RCU handle nohz_full= CPUs

2014-09-07T23:27:30Z

Currently TASKS_RCU would ignore a CPU running a task in nohz_full= usermode execution. There would be neither a context switch nor a scheduling-clock interrupt to tell TASKS_RCU that the task in question had passed through a quiescent state. The grace period would therefore extend indefinitely. This commit therefore makes RCU's dyntick-idle subsystem record the task_struct structure of the task that is running in dyntick-idle mode on each CPU. The TASKS_RCU grace period can then access this information and record a quiescent state on behalf of any CPU running in dyntick-idle usermode. Signed-off-by: Paul E. McKenney

rcu: Add call_rcu_tasks()

2014-09-07T23:27:19Z

This commit adds a new RCU-tasks flavor of RCU, which provides call_rcu_tasks(). This RCU flavor's quiescent states are voluntary context switch (not preemption!) and userspace execution (not the idle loop -- use some sort of schedule_on_each_cpu() if you need to handle the idle tasks. Note that unlike other RCU flavors, these quiescent states occur in tasks, not necessarily CPUs. Includes fixes from Steven Rostedt. This RCU flavor is assumed to have very infrequent latency-tolerant updaters. This assumption permits significant simplifications, including a single global callback list protected by a single global lock, along with a single task-private linked list containing all tasks that have not yet passed through a quiescent state. If experience shows this assumption to be incorrect, the required additional complexity will be added. Suggested-by: Steven Rostedt Signed-off-by: Paul E. McKenney

rcu: Simplify priority boosting by putting rt_mutex in rcu_node

2014-07-09T16:15:01Z

RCU priority boosting currently checks for boosting via a pointer in task_struct. However, this is not needed: As Oleg noted, if the rt_mutex is placed in the rcu_node instead of on the booster's stack, the boostee can simply check it see if it owns the lock. This commit makes this change, shrinking task_struct by one pointer and the kernel by thirteen lines. Suggested-by: Oleg Nesterov Signed-off-by: Paul E. McKenney

Merge git://git.infradead.org/users/eparis/audit

2014-01-24T02:08:10Z

Pull audit update from Eric Paris: "Again we stayed pretty well contained inside the audit system. Venturing out was fixing a couple of function prototypes which were inconsistent (didn't hurt anything, but we used the same value as an int, uint, u32, and I think even a long in a couple of places). We also made a couple of minor changes to when a couple of LSMs called the audit system. We hoped to add aarch64 audit support this go round, but it wasn't ready. I'm disappearing on vacation on Thursday. I should have internet access, but it'll be spotty. If anything goes wrong please be sure to cc rgb@redhat.com. He'll make fixing things his top priority" * git://git.infradead.org/users/eparis/audit: (50 commits) audit: whitespace fix in kernel-parameters.txt audit: fix location of __net_initdata for audit_net_ops audit: remove pr_info for every network namespace audit: Modify a set of system calls in audit class definitions audit: Convert int limit uses to u32 audit: Use more current logging style audit: Use hex_byte_pack_upper audit: correct a type mismatch in audit_syscall_exit() audit: reorder AUDIT_TTY_SET arguments audit: rework AUDIT_TTY_SET to only grab spin_lock once audit: remove needless switch in AUDIT_SET audit: use define's for audit version audit: documentation of audit= kernel parameter audit: wait_for_auditd rework for readability audit: update MAINTAINERS audit: log task info on feature change audit: fix incorrect set of audit_sock audit: print error message when fail to create audit socket audit: fix dangling keywords in audit_log_set_loginuid() output audit: log on errors from filter user rules ...

introduce for_each_thread() to replace the buggy while_each_thread()

2014-01-22T00:19:46Z

while_each_thread() and next_thread() should die, almost every lockless usage is wrong. 1. Unless g == current, the lockless while_each_thread() is not safe. while_each_thread(g, t) can loop forever if g exits, next_thread() can't reach the unhashed thread in this case. Note that this can happen even if g is the group leader, it can exec. 2. Even if while_each_thread() itself was correct, people often use it wrongly. It was never safe to just take rcu_read_lock() and loop unless you verify that pid_alive(g) == T, even the first next_thread() can point to the already freed/reused memory. This patch adds signal_struct->thread_head and task->thread_node to create the normal rcu-safe list with the stable head. The new for_each_thread(g, t) helper is always safe under rcu_read_lock() as long as this task_struct can't go away. Note: of course it is ugly to have both task_struct->thread_node and the old task_struct->thread_group, we will kill it later, after we change the users of while_each_thread() to use for_each_thread(). Perhaps we can kill it even before we convert all users, we can reimplement next_thread(t) using the new thread_head/thread_node. But we can't do this right now because this will lead to subtle behavioural changes. For example, do/while_each_thread() always sees at least one task, while for_each_thread() can do nothing if the whole thread group has died. Or thread_group_empty(), currently its semantics is not clear unless thread_group_leader(p) and we need to audit the callers before we can change it. So this patch adds the new interface which has to coexist with the old one for some time, hopefully the next changes will be more or less straightforward and the old one will go away soon. Signed-off-by: Oleg Nesterov Reviewed-by: Sergey Dyasly Tested-by: Sergey Dyasly Reviewed-by: Sameer Nanda Acked-by: David Rientjes Cc: "Eric W. Biederman" Cc: Frederic Weisbecker Cc: Mandeep Singh Baines Cc: "Ma, Xindong" Cc: Michal Hocko Cc: "Tu, Xiaobing" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

audit: convert all sessionid declaration to unsigned int

2014-01-14T03:31:46Z

Right now the sessionid value in the kernel is a combination of u32, int, and unsigned int. Just use unsigned int throughout. Signed-off-by: Eric Paris Signed-off-by: Richard Guy Briggs Signed-off-by: Eric Paris

rtmutex: Turn the plist into an rb-tree

2014-01-13T12:41:50Z

Turn the pi-chains from plist to rb-tree, in the rt_mutex code, and provide a proper comparison function for -deadline and -priority tasks. This is done mainly because: - classical prio field of the plist is just an int, which might not be enough for representing a deadline; - manipulating such a list would become O(nr_deadline_tasks), which might be to much, as the number of -deadline task increases. Therefore, an rb-tree is used, and tasks are queued in it according to the following logic: - among two -priority (i.e., SCHED_BATCH/OTHER/RR/FIFO) tasks, the one with the higher (lower, actually!) prio wins; - among a -priority and a -deadline task, the latter always wins; - among two -deadline tasks, the one with the earliest deadline wins. Queueing and dequeueing functions are changed accordingly, for both the list of a task's pi-waiters and the list of tasks blocked on a pi-lock. Signed-off-by: Peter Zijlstra Signed-off-by: Dario Faggioli Signed-off-by: Juri Lelli Signed-off-again-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1383831828-15501-10-git-send-email-juri.lelli@gmail.com Signed-off-by: Ingo Molnar

seqcount: Add lockdep functionality to seqcount/seqlock structures

2013-11-06T11:40:26Z

Currently seqlocks and seqcounts don't support lockdep. After running across a seqcount related deadlock in the timekeeping code, I used a less-refined and more focused variant of this patch to narrow down the cause of the issue. This is a first-pass attempt to properly enable lockdep functionality on seqlocks and seqcounts. Since seqcounts are used in the vdso gettimeofday code, I've provided non-lockdep accessors for those needs. I've also handled one case where there were nested seqlock writers and there may be more edge cases. Comments and feedback would be appreciated! Signed-off-by: John Stultz Signed-off-by: Peter Zijlstra Cc: Eric Dumazet Cc: Li Zefan Cc: Mathieu Desnoyers Cc: Steven Rostedt Cc: "David S. Miller" Cc: netdev@vger.kernel.org Link: http://lkml.kernel.org/r/1381186321-4906-3-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar

sched/rt: Add header to

2013-02-19T07:06:01Z

IA64 relied on it through sched.h inclusion: arch/ia64/kernel/init_task.c:38:11: error: 'MAX_PRIO' undeclared here (not in a function) arch/ia64/kernel/init_task.c:38:11: error: 'RR_TIMESLICE' undeclared here (not in a function) Reported-by: kbuild test robot Cc: Clark Williams Cc: Peter Zijlstra Cc: Steven Rostedt Link: http://lkml.kernel.org/n/tip-xaan1twswggedMR0airtpjui@git.kernel.org Signed-off-by: Ingo Molnar