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43 .Nd lightweight buffers
47 .Fn lwbuf_alloc "vm_page_t m" "struct lwbuf *"
49 .Fn lwbuf_free "struct lwbuf *lwb"
51 .Fn lwbuf_page "struct lwbuf *lwb"
53 .Fn lwbuf_kva "struct lwbuf *lwb"
55 .Fn lwbuf_set_global "struct lwbuf *lwb"
59 kernel functions are used for maintaining a lightweight reference to and
60 accessing an arbitrary
64 returns a pointer to a lightweight buffer representing
68 argument is an lwbuf structure, used to avoid allocation of an lwbuf
69 on the x86_64 architecture.
72 frees all resources associated with the lightweight buffer
82 of the lightweight buffer
88 previously obtained through
90 will be valid on all processors without subsequent calls to
92 It should not be used.
93 .Sh IMPLEMENTATION NOTES
98 kernel maintains a direct map of KVA covering all physical memory.
100 Lightweight buffers are thread and cross-processor safe with a number of
102 Allocated buffers are not internally cached or reference counted.
103 Any consumer of lightweight buffers may elect to share allocated buffers
104 or allow them to be used in other threads or on other processors, but care
106 Buffers must be externally refcounted or in some other manner
107 freed only after last use.
111 implementation first appeared in
116 implementation and this manpage were written by
117 .An Samuel J. Greear .