d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Add rms_try_rlock and rms_wowned.

Browse Source
This commit is contained in:
Mateusz Guzik 2020-01-31 08:36:49 +00:00
parent cedad2916e
commit 1a78ac2416
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=357320
2 changed files with 36 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

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_ */