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It is already seven years since mbuf allocator uses same

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M_WAITOK/M_NOWAIT flags as malloc(9). Update manual page.

Submitted by:	Vadim Goncharov <vadimnuclight tpu.ru>
This commit is contained in:
Gleb Smirnoff 2011-04-18 15:30:25 +00:00
parent 20790a105d
commit fa05d2156e
1 changed files with 16 additions and 15 deletions
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31
share/man/man9/mbuf.9
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@ -24,7 +24,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd August 7, 2010
.Dd April 18, 2011
.Dt MBUF 9
.Os
.\"
@ -371,9 +371,9 @@ on failure.
The
.Fa how
argument is to be set to
.Dv M_WAIT
.Dv M_WAITOK
or
.Dv M_DONTWAIT .
.Dv M_NOWAIT .
It specifies whether the caller is willing to block if necessary.
A number of other functions and macros related to
.Vt mbufs
@ -381,15 +381,16 @@ have the same argument because they may
at some point need to allocate new
.Vt mbufs .
.Pp
Programmers should be careful not to confuse the
Historical
.Vt mbuf
allocation flag
.Dv M_DONTWAIT
with the
.Xr malloc 9
allocation flag,
.Dv M_NOWAIT .
They are not the same.
allocator (See
.Sx HISTORY
section) used allocation flags
.Dv M_WAIT
and
.Dv M_DONTWAIT .
These constants are kept for compatibility
and their use in new code is discouraged.
.It Fn MGETHDR mbuf how type
Allocate an
.Vt mbuf
@ -964,9 +965,9 @@ Upon success, the original chain will be freed and the new
chain will be returned.
.Fa how
should be either
.Dv M_WAIT
.Dv M_WAITOK
or
.Dv M_DONTWAIT ,
.Dv M_NOWAIT ,
depending on the caller's preference.
.Pp
This function is especially useful in network drivers, where
@ -982,9 +983,9 @@ The original mbuf chain is always reclaimed and the reference
count of any shared mbuf clusters is decremented.
.Fa how
should be either
.Dv M_WAIT
.Dv M_WAITOK
or
.Dv M_DONTWAIT ,
.Dv M_NOWAIT ,
depending on the caller's preference.
As a side-effect of this process the returned
mbuf chain may be compacted.