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32 .\" $DragonFly: src/share/man/man9/serializer.9,v 1.5 2008/05/15 09:21:40 swildner Exp $
38 .Nm lwkt_serialize_init ,
39 .Nm lwkt_serialize_enter ,
40 .Nm lwkt_serialize_adaptive_enter ,
41 .Nm lwkt_serialize_try ,
42 .Nm lwkt_serialize_exit ,
43 .Nm lwkt_serialize_handler_enable ,
44 .Nm lwkt_serialize_handler_disable ,
45 .Nm lwkt_serialize_handler_call ,
46 .Nm lwkt_serialize_handler_try ,
49 .Nm ASSERT_NOT_SERIALIZED
50 .Nd generic low level serializer
54 .Fn lwkt_serialize_init "lwkt_serialize_t s"
56 .Fn lwkt_serialize_enter "lwkt_serialize_t s"
58 .Fn lwkt_serialize_adaptive_enter "lwkt_serialize_t s"
60 .Fn lwkt_serialize_try "lwkt_serialize_t s"
62 .Fn lwkt_serialize_exit "lwkt_serialize_t s"
64 .Fn lwkt_serialize_handler_enable "lwkt_serialize_t s"
66 .Fn lwkt_serialize_handler_disable "lwkt_serialize_t s"
68 .Fo lwkt_serialize_handler_call
69 .Fa "lwkt_serialize_t s"
70 .Fa "void (*func)(void *, void *)"
75 .Fo lwkt_serialize_handler_try
76 .Fa "lwkt_serialize_t s"
77 .Fa "void (*func)(void *, void *)"
82 .Fn ASSERT_SERIALIZED "s"
83 .Fn ASSERT_NOT_SERIALIZED "s"
87 API provides a fast locked-bus-cycle-based serialization facility
88 that will serialize across blocking conditions.
89 It is very similar to a lock but much faster for the common case.
91 This API was initially designed to be a replacement for SPL calls, but
92 may be used whenever a low level exclusive lock (serialization) and/or
93 interrupt/device interaction is required.
94 Unlike tokens this serialization is not safe from deadlocks nor is it
95 recursive, and care must be taken when using it.
98 will not release a serializer that is being held.
100 There are two primary facilities \(em the serializer facility itself and
101 an integrated non-stackable interrupt handler disablement facility
104 .Fn lwkt_serialize_init ,
105 .Fn lwkt_serialize_enter
107 .Fn lwkt_serialize_exit
108 respectively initialize, hold and release the serializer
110 .Fn lwkt_serialize_try
111 is a non-blocking version of
112 .Fn lwkt_serialize_enter .
114 .Fn lwkt_serialize_adaptive_enter
115 is a special version of
116 .Fn lwkt_serialize_enter
117 which will try to spin a bit before the current thread is put to sleep
122 .Fn lwkt_serialize_adaptive_enter
123 favors spinning over sleeping.
124 This behavior can be changed by tuning the
125 .Va debug.serialize_bolimit
127 .Va debug.serialize_boround
131 .Fn lwkt_serialize_adaptive_enter
132 is only available in SMP kernels.
134 .Fn lwkt_serialize_handler_disable ,
135 .Fn lwkt_serialize_handler_enable
137 .Fn lwkt_serialize_handler_call
138 respectively disable, enable and call an interrupt handler
146 will be passed to the handler.
147 .Fn lwkt_serialize_handler_try
148 is a non-blocking version of
149 .Fn lwkt_serialize_handler_call .
153 macro tests if the serializer
157 .Fn ASSERT_SERIALIZED
159 .Fn ASSERT_NOT_SERIALIZED
160 macros assert that the serializer
162 is being held/not held.
165 .Fn lwkt_serialize_try
167 .Fn lwkt_serialize_handler_try
168 functions return 0 on success and 1 on failure.
170 .Pa sys/kern/lwkt_serialize.c
173 .Xr serialize_sleep 9 ,
178 API first appeared in
186 This manual page was written by