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Add rms_try_rlock and rms_wowned.

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This commit is contained in:
mjg 2020-01-31 08:36:49 +00:00
parent ed84722e02
commit 86c92abdd3
2 changed files with 36 additions and 0 deletions
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24
sys/kern/kern_rmlock.c
View File

@ -934,6 +934,30 @@ rms_rlock(struct rmslock *rms)
critical_exit();
}
int
rms_try_rlock(struct rmslock *rms)
{
int *influx;
critical_enter();
influx = zpcpu_get(rms->readers_influx);
__compiler_membar();
*influx = 1;
__compiler_membar();
if (__predict_false(rms->writers > 0)) {
__compiler_membar();
*influx = 0;
critical_exit();
return (0);
}
__compiler_membar();
(*zpcpu_get(rms->readers_pcpu))++;
__compiler_membar();
*influx = 0;
critical_exit();
return (1);
}
static void __noinline
rms_runlock_fallback(struct rmslock *rms)
{

12
sys/sys/rmlock.h
View File

@ -136,9 +136,21 @@ struct rm_args {
void rms_init(struct rmslock *rms, const char *name);
void rms_destroy(struct rmslock *rms);
void rms_rlock(struct rmslock *rms);
int rms_try_rlock(struct rmslock *rms);
void rms_runlock(struct rmslock *rms);
void rms_wlock(struct rmslock *rms);
void rms_wunlock(struct rmslock *rms);
/*
* Writers are not explicitly tracked, thus until that changes the best we can
* do is indicate the lock is taken for writing by *someone*.
*/
static inline int
rms_wowned(struct rmslock *rms)
{
return (rms->writers > 0);
}
#endif /* _KERNEL */
#endif /* !_SYS_RMLOCK_H_ */