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36 .Nm lwkt_serialize_init ,
37 .Nm lwkt_serialize_enter ,
38 .Nm lwkt_serialize_adaptive_enter ,
39 .Nm lwkt_serialize_try ,
40 .Nm lwkt_serialize_exit ,
41 .Nm lwkt_serialize_handler_enable ,
42 .Nm lwkt_serialize_handler_disable ,
43 .Nm lwkt_serialize_handler_call ,
44 .Nm lwkt_serialize_handler_try ,
46 .Nm ASSERT_NOT_SERIALIZED
47 .Nd generic low level serializer
51 .Fn lwkt_serialize_init "lwkt_serialize_t s"
53 .Fn lwkt_serialize_enter "lwkt_serialize_t s"
55 .Fn lwkt_serialize_adaptive_enter "lwkt_serialize_t s"
57 .Fn lwkt_serialize_try "lwkt_serialize_t s"
59 .Fn lwkt_serialize_exit "lwkt_serialize_t s"
61 .Fn lwkt_serialize_handler_enable "lwkt_serialize_t s"
63 .Fn lwkt_serialize_handler_disable "lwkt_serialize_t s"
65 .Fo lwkt_serialize_handler_call
66 .Fa "lwkt_serialize_t s"
67 .Fa "void (*func)(void *, void *)"
72 .Fo lwkt_serialize_handler_try
73 .Fa "lwkt_serialize_t s"
74 .Fa "void (*func)(void *, void *)"
78 .Fn ASSERT_SERIALIZED "s"
79 .Fn ASSERT_NOT_SERIALIZED "s"
83 API provides a fast locked-bus-cycle-based serialization facility
84 that will serialize across blocking conditions.
85 It is very similar to a lock but much faster for the common case.
87 This API was initially designed to be a replacement for SPL calls, but
88 may be used whenever a low level exclusive lock (serialization) and/or
89 interrupt/device interaction is required.
90 Unlike tokens this serialization is not safe from deadlocks nor is it
91 recursive, and care must be taken when using it.
94 will not release a serializer that is being held.
96 There are two primary facilities \(em the serializer facility itself and
97 an integrated non-stackable interrupt handler disablement facility
100 .Fn lwkt_serialize_init ,
101 .Fn lwkt_serialize_enter
103 .Fn lwkt_serialize_exit
104 respectively initialize, hold and release the serializer
106 .Fn lwkt_serialize_try
107 is a non-blocking version of
108 .Fn lwkt_serialize_enter .
110 .Fn lwkt_serialize_adaptive_enter
111 is a special version of
112 .Fn lwkt_serialize_enter
113 which will try to spin a bit before the current thread is put to sleep
118 .Fn lwkt_serialize_adaptive_enter
119 favors spinning over sleeping.
120 This behavior can be changed by tuning the
121 .Va debug.serialize_bolimit
123 .Va debug.serialize_boround
127 .Fn lwkt_serialize_adaptive_enter
128 is only available in SMP kernels.
130 .Fn lwkt_serialize_handler_disable ,
131 .Fn lwkt_serialize_handler_enable
133 .Fn lwkt_serialize_handler_call
134 respectively disable, enable and call an interrupt handler
142 will be passed to the handler.
143 .Fn lwkt_serialize_handler_try
144 is a non-blocking version of
145 .Fn lwkt_serialize_handler_call .
148 .Fn ASSERT_SERIALIZED
150 .Fn ASSERT_NOT_SERIALIZED
151 macros assert that the serializer
153 is being held/not held.
156 .Fn lwkt_serialize_try
158 .Fn lwkt_serialize_handler_try
159 functions return 0 on success and 1 on failure.
161 The serializer itself is implemented in
162 .Pa /sys/kern/lwkt_serialize.c .
164 .Pa /sys/sys/serialize.h
165 describes the public interface and the structure of a serializer.
173 API first appeared in
181 This manual page was written by