Change 114172 by [email protected]_cinnamon on 2007/02/07 11:48:03
Update bpf(4) man page for BIOCROTZBUF ioctl, and improve the
documentation about buffers a bit. The man page is not yet updated
for the shared memory header and ACK model.
Affected files ...
.. //depot/projects/zcopybpf/src/share/man/man4/bpf.4#3 edit
==== //depot/projects/zcopybpf/src/share/man/man4/bpf.4#3 (text+ko) ====
@@ -425,20 +425,37 @@
must be filled out.
.It Dv BIOCGETZMAX
-.Pq Li u_int
+.Pq Li size_t
Get the largest individual zero-copy buffer size allowed.
As two buffers are used in zero-copy buffer mode, the limit (in practice) is
-twice this size.
+twice the returned size.
As zero-copy buffers consume kernel address space, conservative selection of
buffer size, especially when there are multiple
descriptors in use on 32-bit systems.
.It Dv BIOCGETZNEXT
+.It Dv BIOCROTZBUF
.Pq Li struct bpf_zbuf
-Get the buffer pointer of the next completed zero-copy buffer and length of
-pending data, or
+Get the buffer pointer and length of the next zero-copy buffer buffer ready
+for userspace use, or
+if there is no pending buffer.
+queries for the next completely filled buffer ready for immediate use,
+returning NULL if there are only empty or partially filled buffers available.
+queries for a filled buffer, but in the event there is only a partially
+filled buffer, will make that buffer available for userspace to use
+This allows consumers of zero-copy buffering to implement timeouts and
+retrieve partially filled buffers.
-if there is no pending completed buffer.
+only if no data is present in either of the zero-copy buffers.
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