diff options
Diffstat (limited to 'share/man/man9/mutex.9')
| -rw-r--r-- | share/man/man9/mutex.9 | 46 |
1 files changed, 35 insertions, 11 deletions
diff --git a/share/man/man9/mutex.9 b/share/man/man9/mutex.9 index c7cc1ef..5865165 100644 --- a/share/man/man9/mutex.9 +++ b/share/man/man9/mutex.9 @@ -28,7 +28,7 @@ .\" from BSDI $Id: mutex.4,v 1.1.2.3 1998/04/27 22:53:13 ewv Exp $ .\" $FreeBSD$ .\" -.Dd November 16, 2011 +.Dd July 18, 2016 .Dt MUTEX 9 .Os .Sh NAME @@ -41,6 +41,8 @@ .Nm mtx_lock_spin_flags , .Nm mtx_trylock , .Nm mtx_trylock_flags , +.Nm mtx_trylock_spin , +.Nm mtx_trylock_spin_flags , .Nm mtx_unlock , .Nm mtx_unlock_spin , .Nm mtx_unlock_flags , @@ -73,6 +75,10 @@ .Ft int .Fn mtx_trylock_flags "struct mtx *mutex" "int flags" .Ft void +.Fn mtx_trylock_spin "struct mtx *mutex" +.Ft int +.Fn mtx_trylock_spin_flags "struct mtx *mutex" "int flags" +.Ft void .Fn mtx_unlock "struct mtx *mutex" .Ft void .Fn mtx_unlock_spin "struct mtx *mutex" @@ -245,26 +251,33 @@ argument, then the mutex can be acquired recursively. .Pp The .Fn mtx_trylock -attempts to acquire the +and +.Fn mtx_trylock_spin +functions attempt to acquire a .Dv MTX_DEF -mutex pointed to by +or +.Dv MTX_SPIN +mutex, respectively, pointed to by .Fa mutex . -If the mutex cannot be immediately acquired -.Fn mtx_trylock -will return 0, -otherwise the mutex will be acquired -and a non-zero value will be returned. +If the mutex cannot be immediately acquired, the functions will return 0, +otherwise the mutex will be acquired and a non-zero value will be returned. .Pp The .Fn mtx_trylock_flags -function has the same behavior as +and +.Fn mtx_trylock_spin_flags +functions have the same behavior as .Fn mtx_trylock -but should be used when the caller desires to pass in a +and +.Fn mtx_trylock_spin +respectively, but should be used when the caller desires to pass in a .Fa flags value. Presently, the only valid value in the .Fn mtx_trylock -case is +and +.Fn mtx_trylock_spin +cases is .Dv MTX_QUIET , and its effects are identical to those described for .Fn mtx_lock @@ -443,6 +456,13 @@ while any spin lock is held. .It Dv MTX_RECURSE Specifies that the initialized mutex is allowed to recurse. This bit must be present if the mutex is permitted to recurse. +.Pp +Note that neither +.Fn mtx_trylock +nor +.Fn mtx_trylock_spin +support recursion; +that is, attempting to acquire an already-owned mutex fails. .It Dv MTX_QUIET Do not log any mutex operations for this lock. .It Dv MTX_NOWITNESS @@ -528,3 +548,7 @@ functions appeared in .Bsx 4.1 and .Fx 5.0 . +The +.Fn mtx_trylock_spin +function was added in +.Fx 12.0 . |
