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#ifndef FUTEXMGR
#define FUTEXMGR
/**
* @file futexmgr.H
* @brief Declaration for kernel side futex management
*/
#include <stdint.h>
#include <util/locked/list.H>
#include <kernel/spinlock.H>
struct task_t;
/**
* @class FutexManager
* Kernel internal management of fuxtexs
*/
class FutexManager
{
public:
/**
* Put the current processes on a wait queue
* @param[in] i_task pointer to the current task structure
* @param[in] i_addr Futex address
* @param[in] i_val Value that *i_addr should contain
* @returns [0 | error code] if *i_addr != i_val returns EWOULDBLOCK
*/
static uint64_t wait(task_t * i_task, uint64_t * i_addr, uint64_t i_val);
/**
* Wakeup threads
* @param[in] i_addr pointer to a futex
* @param[in] i_count The max number of threads to wake
* @returns The number of threads awoken
*/
static uint64_t wake(uint64_t * i_addr, uint64_t i_count);
protected:
/**
* Ctor
*/
FutexManager() {};
/**
* Dtor
*/
~FutexManager() {};
private: // functions
/**
* Put the current processes on a wait queue
* @param[in] i_task pointer to the current task structure
* @param[in] i_addr Futex address
* @param[in] i_val Value that *i_addr should contain
* @returns [0 | error code] if *i_addr != i_val returns EWOULDBLOCK
*/
uint64_t _wait(task_t * i_task, uint64_t * i_addr, uint64_t i_val);
/**
* Wakeup threads
* @param[in] i_addr pointer to a futex
* @param[in] i_count The max number of threads to wake
* @returns The number of threads awoken
*/
uint64_t _wake(uint64_t * i_addr, uint64_t i_count);
private: // data
struct _FutexWait_t
{
_FutexWait_t * next; ///< next _FutexWait_t in list
_FutexWait_t * prev; ///< prev _FutexWait_t in list
uint64_t * key; ///< search key is futex address
task_t* task; ///< task on wait list
};
typedef Util::Locked::List<_FutexWait_t, uint64_t *> FutexList_t;
Spinlock iv_lock; ///< lock
FutexList_t iv_list; ///< List of waiting tasks for all futexes
};
#endif
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