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Diffstat (limited to 'doc/ck_swlock')
| -rw-r--r-- | doc/ck_swlock | 138 |
1 files changed, 0 insertions, 138 deletions
diff --git a/doc/ck_swlock b/doc/ck_swlock deleted file mode 100644 index e101334814f3..000000000000 --- a/doc/ck_swlock +++ /dev/null @@ -1,138 +0,0 @@ -.\" -.\" Copyright 2014 Samy Al Bahra. -.\" All rights reserved. -.\" -.\" Redistribution and use in source and binary forms, with or without -.\" modification, are permitted provided that the following conditions -.\" are met: -.\" 1. Redistributions of source code must retain the above copyright -.\" notice, this list of conditions and the following disclaimer. -.\" 2. Redistributions in binary form must reproduce the above copyright -.\" notice, this list of conditions and the following disclaimer in the -.\" documentation and/or other materials provided with the distribution. -.\" -.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND -.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE -.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE -.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE -.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL -.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS -.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) -.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT -.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY -.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF -.\" SUCH DAMAGE. -.\" -.\" -.Dd April 22, 2014. -.Dt ck_swlock 3 -.Sh NAME -.Nm ck_swlock_init , -.Nm ck_swlock_write_latch , -.Nm ck_swlock_write_unlatch , -.Nm ck_swlock_write_lock , -.Nm ck_swlock_write_unlock , -.Nm ck_swlock_write_trylock , -.Nm ck_swlock_write_downgrade , -.Nm ck_swlock_locked_writer , -.Nm ck_swlock_read_lock , -.Nm ck_swlock_read_trylock , -.Nm ck_swlock_read_unlock , -.Nm ck_swlock_locked_reader -.Nd centralized copy-safe write-biased single-writer read-write locks -.Sh LIBRARY -Concurrency Kit (libck, \-lck) -.Sh SYNOPSIS -.In ck_swlock.h -.Pp -.Dv ck_swlock_t lock = CK_SWLOCK_INITIALIZER; -.Pp -.Ft void -.Fn ck_swlock_init "ck_swlock_t *lock" -.Ft void -.Fn ck_swlock_write_lock "ck_swlock_t *lock" -.Ft void -.Fn ck_swlock_write_unlock "ck_swlock_t *lock" -.Ft void -.Fn ck_swlatch_write_latch "ck_swlatch_t *latch" -.Ft void -.Fn ck_swlatch_write_unlatch "ck_swlatch_t *latch" -.Ft bool -.Fn ck_swlock_write_trylock "ck_swlock_t *lock" -.Ft bool -.Fn ck_swlock_write_downgrade "ck_swlock_t *lock" -.Ft bool -.Fn ck_swlock_locked_writer "ck_swlock_t *lock" -.Ft void -.Fn ck_swlock_read_lock "ck_swlock_t *lock" -.Ft bool -.Fn ck_swlock_read_trylock "ck_swlock_t *lock" -.Ft void -.Fn ck_swlock_read_unlock "ck_swlock_t *lock" -.Ft bool -.Fn ck_swlock_locked_reader "ck_swlock_t *lock" -.Sh DESCRIPTION -This is a centralized write-biased single-writer reader-writer lock. It -requires half the space that ck_rwlock does and has a low latency -fast path. The lock supports latch and unlatch operations that -allow it to be used in a copy-safe manner (reader-bits may be -over-written safely). -.Sh EXAMPLE -.Bd -literal -offset indent -#include <ck_swlock.h> - -static ck_swlock_t lock = CK_SWLOCK_INITIALIZER; - -static void -reader(void) -{ - - for (;;) { - ck_swlock_read_lock(&lock); - /* Read-side critical section. */ - ck_swlock_read_unlock(&lock); - - if (ck_swlock_read_trylock(&lock) == true) { - /* Read-side critical section. */ - ck_swlock_read_unlock(&lock); - } - } - - return; -} - -static void -writer(void) -{ - ck_swlock_t contrived; - - for (;;) { - ck_swlock_write_lock(&lock); - /* Write-side critical section. */ - ck_swlock_write_unlock(&lock); - - if (ck_swlock_write_trylock(&lock) == true) { - /* Write-side critical section. */ - ck_swlock_write_unlock(&lock); - } - - ck_swlock_write_latch(&lock); - /* Write-side critical section. */ - - /* This is safe to do with-in a latch. */ - contrived = lock; - lock = contrived; - ck_swlock_write_unlatch(&lock); - } - - return; -} -.Ed -.Sh SEE ALSO -.Xr ck_brlock 3 , -.Xr ck_elide 3 , -.Xr ck_pflock 3 , -.Xr ck_rwlock 3 , -.Xr ck_tflock 3 -.Pp -Additional information available at http://concurrencykit.org/ |