svn commit: r220787 - head/share/man/man9
Gleb Smirnoff
glebius at FreeBSD.org
Mon Apr 18 15:30:25 UTC 2011
Author: glebius
Date: Mon Apr 18 15:30:25 2011
New Revision: 220787
URL: http://svn.freebsd.org/changeset/base/220787
Log:
It is already seven years since mbuf allocator uses same
M_WAITOK/M_NOWAIT flags as malloc(9). Update manual page.
Submitted by: Vadim Goncharov <vadimnuclight tpu.ru>
Modified:
head/share/man/man9/mbuf.9
Modified: head/share/man/man9/mbuf.9
==============================================================================
--- head/share/man/man9/mbuf.9 Mon Apr 18 14:34:10 2011 (r220786)
+++ head/share/man/man9/mbuf.9 Mon Apr 18 15:30:25 2011 (r220787)
@@ -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
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 reclai
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.
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