f3de9af633
kit, CK, in the LinuxKPI. When threads are pinned to a CPU core or when there is only one CPU, it can happen that a higher priority thread can call the CK synchronize function while a lower priority thread holds the read lock. Because the CK's synchronize is a simple wait loop this can lead to a deadlock situation. To solve this problem use the recently introduced CK's wait callback function. When detecting a CK blocking condition figure out the lowest priority among the blockers and update the calling thread's priority and yield. If another CPU core is holding the read lock, pin the thread to the blocked CPU core and update the priority. The calling threads priority and CPU bindings are restored before return. If a thread holding a CK read lock is detected to be sleeping, pause() will be used instead of yield(). MFC after: 1 week Sponsored by: Mellanox Technologies
159 lines
4.3 KiB
C
159 lines
4.3 KiB
C
/*-
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* Copyright (c) 2010 Isilon Systems, Inc.
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* Copyright (c) 2010 iX Systems, Inc.
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* Copyright (c) 2010 Panasas, Inc.
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* Copyright (c) 2013-2017 Mellanox Technologies, Ltd.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice unmodified, this list of conditions, and the following
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* disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _LINUX_SCHED_H_
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#define _LINUX_SCHED_H_
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/proc.h>
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#include <sys/sched.h>
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#include <sys/sleepqueue.h>
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#include <linux/list.h>
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#include <linux/compat.h>
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#include <linux/completion.h>
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#include <linux/pid.h>
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#include <linux/slab.h>
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#include <linux/mm_types.h>
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#include <linux/string.h>
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#include <linux/bitmap.h>
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#include <asm/atomic.h>
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#define MAX_SCHEDULE_TIMEOUT LONG_MAX
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#define TASK_RUNNING 0
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#define TASK_INTERRUPTIBLE 1
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#define TASK_UNINTERRUPTIBLE 2
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#define TASK_DEAD 64
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#define TASK_WAKEKILL 128
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#define TASK_WAKING 256
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struct task_struct {
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struct thread *task_thread;
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struct mm_struct *mm;
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linux_task_fn_t *task_fn;
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void *task_data;
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int task_ret;
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atomic_t usage;
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int state;
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atomic_t kthread_flags;
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pid_t pid; /* BSD thread ID */
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const char *comm;
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void *bsd_ioctl_data;
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unsigned bsd_ioctl_len;
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struct completion parked;
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struct completion exited;
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TAILQ_ENTRY(task_struct) rcu_entry;
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int rcu_recurse;
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};
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#define current ({ \
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struct thread *__td = curthread; \
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linux_set_current(__td); \
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((struct task_struct *)__td->td_lkpi_task); \
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})
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#define task_pid_group_leader(task) (task)->task_thread->td_proc->p_pid
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#define task_pid(task) ((task)->pid)
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#define task_pid_nr(task) ((task)->pid)
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#define get_pid(x) (x)
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#define put_pid(x) do { } while (0)
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#define current_euid() (curthread->td_ucred->cr_uid)
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#define set_current_state(x) \
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atomic_store_rel_int((volatile int *)¤t->state, (x))
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#define __set_current_state(x) current->state = (x)
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static inline void
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get_task_struct(struct task_struct *task)
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{
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atomic_inc(&task->usage);
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}
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static inline void
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put_task_struct(struct task_struct *task)
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{
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if (atomic_dec_and_test(&task->usage))
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linux_free_current(task);
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}
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#define schedule() \
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do { \
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void *c; \
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\
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if (cold || SCHEDULER_STOPPED()) \
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break; \
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c = curthread; \
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sleepq_lock(c); \
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if (current->state == TASK_INTERRUPTIBLE || \
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current->state == TASK_UNINTERRUPTIBLE) { \
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sleepq_add(c, NULL, "task", SLEEPQ_SLEEP, 0); \
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sleepq_wait(c, 0); \
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} else { \
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sleepq_release(c); \
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sched_relinquish(curthread); \
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} \
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} while (0)
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#define wake_up_process(x) \
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do { \
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int wakeup_swapper; \
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void *c; \
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\
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c = (x)->task_thread; \
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sleepq_lock(c); \
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(x)->state = TASK_RUNNING; \
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wakeup_swapper = sleepq_signal(c, SLEEPQ_SLEEP, 0, 0); \
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sleepq_release(c); \
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if (wakeup_swapper) \
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kick_proc0(); \
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} while (0)
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#define cond_resched() if (!cold) sched_relinquish(curthread)
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#define sched_yield() sched_relinquish(curthread)
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static inline long
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schedule_timeout(signed long timeout)
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{
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if (timeout < 0)
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return 0;
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pause("lstim", timeout);
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return 0;
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}
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#define need_resched() (curthread->td_flags & TDF_NEEDRESCHED)
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#endif /* _LINUX_SCHED_H_ */
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