Module Name: src
Committed By: jruoho
Date: Tue Apr 13 06:05:56 UTC 2010
Modified Files:
src/share/man/man9: cpu_switchto.9
Log Message:
Improvements to wording and markup.
To generate a diff of this commit:
cvs rdiff -u -r1.10 -r1.11 src/share/man/man9/cpu_switchto.9
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/share/man/man9/cpu_switchto.9
diff -u src/share/man/man9/cpu_switchto.9:1.10 src/share/man/man9/cpu_switchto.9:1.11
--- src/share/man/man9/cpu_switchto.9:1.10 Sun May 25 20:00:30 2008
+++ src/share/man/man9/cpu_switchto.9 Tue Apr 13 06:05:56 2010
@@ -1,4 +1,4 @@
-.\" $NetBSD: cpu_switchto.9,v 1.10 2008/05/25 20:00:30 wiz Exp $
+.\" $NetBSD: cpu_switchto.9,v 1.11 2010/04/13 06:05:56 jruoho Exp $
.\"
.\" Copyright (c)2007 YAMAMOTO Takashi,
.\" All rights reserved.
@@ -25,13 +25,15 @@
.\" SUCH DAMAGE.
.\"
.\" ------------------------------------------------------------
-.Dd May 21, 2007
+.Dd April 13, 2010
.Dt CPU_SWITCHTO 9
.Os
.\" ------------------------------------------------------------
.Sh NAME
.Nm cpu_switchto
-.Nd machine-dependent LWP context switching interface
+.Nd machine-dependent
+.Tn LWP
+context switching interface
.\" ------------------------------------------------------------
.Sh SYNOPSIS
.In sys/cpu.h
@@ -41,72 +43,97 @@
"lwp_t *oldlwp" "lwp_t *newlwp" "bool returning"
.\" ------------------------------------------------------------
.Sh DESCRIPTION
+The
.Fn cpu_switchto
-saves the context of the LWP which is currently running on the processor,
-and restores the context of the LWP specified by
+function saves the context of the
+.Tn LWP
+which is currently running on the processor,
+and restores the context of the
+.Tn LWP
+specified by
.Fa newlwp .
.Pp
+Remarks:
+.Bl -enum -offset indent
+.It
.Fn cpu_switchto
-doesn't switch address spaces.
-.Pp
+does not switch address spaces.
+.It
.Fn cpu_switchto
sets
-.Dv curlwp
+.Xr curlwp 9
to
.Fa newlwp .
-.Pp
+.It
.Fn cpu_switchto
should be called at
.Dv IPL_SCHED .
-When
-.Fn cpu_switchto
-returns, the caller should lower the priority level as soon as possible.
-.Pp
+When the function returns, the caller should lower
+the priority level as soon as possible.
+.It
.Fn cpu_switchto
might be called with spin mutexes held.
+.El
.Pp
-It takes the following arguments.
-.Bl -tag -width oldlwp
+The function takes the following arguments.
+.Bl -tag -width "returning " -offset indent
.It Fa oldlwp
-Specify the lwp from which we are going to switch, i.e.,
-the calling LWP.
+Specify the
+.Tn LWP
+from which the switch is going to be made, i.e., the calling
+.Tn LWP .
If it was
.Dv NULL ,
-the context of the LWP currently running on this processor is not saved.
+the context of the
+.Tn LWP
+currently running on this processor is not saved.
.It Fa newlwp
-Specify the lwp to which we are going to switch.
+Specify the
+.Tn LWP
+to which to switch.
It must not be
.Dv NULL .
.It Fa returning
Only meaningful if the architecture implements fast software interrupts.
If true, it indicates that
.Fa oldlwp
-is a soft interrupt LWP that is blocking.
-It's a good indication that any kind of address space or user activity
+is a soft interrupt
+.Tn LWP
+that is blocking.
+It is a good indication that any kind of address space or user activity
can be completely ignored.
For example:
-.Fn ras_lookup ,
-cache flushes, TLB wirings, adjusting lazy FPU
+.Xr ras_lookup 9 ,
+cache flushes, TLB wirings, adjusting lazy
+.Tn FPU
state.
All that is required is to restore the register state and stack, and
-return to the interrupted LWP.
+return to the interrupted
+.Tn LWP .
.El
.\" ------------------------------------------------------------
.Sh RETURN VALUES
+The
.Fn cpu_switchto
-does not return until another LWP calls
-.Fn cpu_switchto
-to switch to us.
+function does not return until another
+.Tn LWP
+calls
+.Fn cpu_switchto .
It returns the
-.Dv oldlwp
+.Vt oldlwp
argument of the
.Fn cpu_switchto
-which is called to switch back to our LWP.
-It's either an LWP which called
-.Fa cpu_switchto
+which is called to switch back to our
+.Tn LWP .
+It is either a
+.Tn LWP
+which called
+.Fn cpu_switchto
to switch to us or
.Dv NULL
-in the case that the LWP was exiting.
+in case the
+.Tn LWP
+was exiting.
.\" ------------------------------------------------------------
.Sh SEE ALSO
.Xr swapcontext 3 ,
