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cygserver: Revamp thread sleep handling

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The current implementation is a very simple approach to implement
a statically sized sleep queue.  The problem is that this code requires
a certain amount of synchronization because the slots in the queue are
used dynamically.  To top it off, the Event objects used for sync'ing
are created and destroyed on demand.  This is complicated, slow, and
error prone.

There's also a blatant bug here: The number of slots in the queue was
wrongly computed in size.  It was too small if XSI IPC was used a lot.

Make the code more robust.  Let the queue have the right size.  Every
slot is now used for a specific IPC object.  All sync objects (switched
to Semaphores) are only created when first required, but never destroyed.
This reduces the usage of a critical section to the creation of a new
sync object.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This commit is contained in:
Corinna Vinschen
2017-03-24 16:45:32 +01:00
parent 0b73dba4de
commit b80b2c0119
5 changed files with 71 additions and 99 deletions
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14
winsup/cygserver/bsd_mutex.h
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@ -26,6 +26,12 @@ struct mtx {
unsigned long cnt;
};
enum ipc_type {
SHM,
MSQ,
SEM
};
/* Some BSD kernel global mutex. */
extern struct mtx Giant;
@ -41,10 +47,10 @@ void _mtx_unlock (mtx *, const char *, int);
void mtx_destroy (mtx *);
void msleep_init (void);
int _msleep (void *, struct mtx *, int, const char *, int, struct thread *);
#define msleep(i,m,p,w,t) _msleep((i),(m),(p),(w),(t),(td))
#define tsleep(i,p,w,t) _msleep((i),NULL,(p),(w),(t),(td))
int wakeup (void *);
int _sleep (ipc_type, int, struct mtx *, int, const char *, int, struct thread *);
#define _msleep(T,i,m,p,w,t) _sleep((T),(i),(m),(p),(w),(t),(td))
#define _tsleep(T,i,p,w,t) _sleep((T),(i),NULL,(p),(w),(t),(td))
int _wakeup (ipc_type, int);
void wakeup_all (void);
#endif /* _BSD_MUTEX_H */