diff options
| -rw-r--r-- | share/man/man9/Makefile | 3 | ||||
| -rw-r--r-- | share/man/man9/swi.9 | 203 |
2 files changed, 205 insertions, 1 deletions
diff --git a/share/man/man9/Makefile b/share/man/man9/Makefile index 7421c10..77e80c2 100644 --- a/share/man/man9/Makefile +++ b/share/man/man9/Makefile @@ -16,7 +16,7 @@ MAN9= CONDSPLASSERT.9 KASSERT.9 MD5.9 SPLASSERT.9 \ devtoname.9 fetch.9 ifnet.9 inittodr.9 intro.9 kernacc.9 malloc.9 \ make_dev.9 microseq.9 mi_switch.9 mutex.9 namei.9 panic.9 pfil.9 physio.9 \ posix4.9 psignal.9 random.9 resettodr.9 rtalloc.9 rtentry.9 sleep.9 spl.9 \ - store.9 style.9 suser.9 time.9 timeout.9 uio.9 \ + store.9 style.9 suser.9 swi.9 time.9 timeout.9 uio.9 \ vget.9 vnode.9 vput.9 vref.9 vrele.9 vslock.9 \ mbuf.9 microtime.9 microuptime.9 tvtohz.9 @@ -92,6 +92,7 @@ MLINKS+=spl.9 splbio.9 spl.9 splclock.9 spl.9 splhigh.9 spl.9 splimp.9 MLINKS+=spl.9 splnet.9 spl.9 splsoftclock.9 spl.9 splsofttty.9 MLINKS+=spl.9 splstatclock.9 spl.9 spltty.9 spl.9 splvm.9 spl.9 splx.9 MLINKS+=store.9 subyte.9 store.9 suswintr.9 store.9 susword.9 store.9 suword.9 +MLINKS+=swi.9 sched_swi.9 swi.9 sinthand_add.9 MLINKS+=time.9 boottime.9 time.9 mono_time.9 time.9 runtime.9 MLINKS+=timeout.9 untimeout.9 MLINKS+=timeout.9 callout_handle_init.9 timeout.9 callout_init.9 diff --git a/share/man/man9/swi.9 b/share/man/man9/swi.9 new file mode 100644 index 0000000..7adfeae --- /dev/null +++ b/share/man/man9/swi.9 @@ -0,0 +1,203 @@ +.\" Copyright (c) 2000 John H. Baldwin +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" $FreeBSD$ +.\" +.Dd October 30, 2000 +.Dt SWI 9 +.Os +.Sh NAME +.Nm sched_swi , +.Nm sinthand_add +.Nd register and schedule software interrupt handlers +.Sh SYNOPSIS +.Fd #include <sys/bus.h> +.Fd #include <sys/proc.h> +.Fd #include <sys/interrupt.h> +.Vt extern struct ithd *tty_ithd; +.Vt extern struct ithd *clk_ithd; +.Vt extern struct intrhand *net_ih; +.Vt extern struct intrhand *softclock_ih; +.Vt extern struct intrhand *vm_ih; +.Ft void +.Fn sched_swi "struct intrhand *handler" "int flags" +.Ft struct intrhand * +.Fo sinthand_add +.Fa "const char *name" +.Fa "struct ithd **thread" +.Fa "driver_intr_t handler" +.Fa "void *arg" +.Fa "int pri" +.Fa "int flags" +.Fc +.Sh DESCRIPTION +These functions are used to register and schedule software interrupt handlers. +Software interrupt handlers are attached to a software interrupt thread, just +as hardware interrupt handlers are attached to a hardware interrupt thread. +This means that multiple handlers can be attached to the same thread. +Software interrupt handlers can be used to queue up less critical processing +inside of hardware interrupt handlers so that the work can be done at a later +time. +Software interrupt threads are different from other kernel threads in that they +are treated as an interrupt thread. +This means that time spent executing these threads is counted as interrupt +time, and that they can be run via a lightweight context switch during +.Fn ast . +.Pp +The +.Fn sinthand_add +function is used to register a new software interrupt handler. +The +.Fa name +argument is used to associate a name with a specific handler. +This name is appended to the name of the software interrupt thread that this +handler is attached to. +The +.Fa thread +argument is an optional pointer to a +.Li struct ithd +pointer. +If this argument points to an existing software interrupt thread, then this +handler will be attached to that thread. +Otherwise a new thread will be created, and if +.Fa thread +is not +.Dv NULL , +then the pointer at that address to will be modified to point to the +newly created thread. +The +.Fa handler +is the function that will be called when the handler is scheduled to run. +The +.Fa arg +parameter will be passed in as the only parameter to +.Fa handler +when the function is executed. +The +.Fa pri +value specifies the priority to assign to an interrupt thread if one is created, +and the +.Fa flags +argument is used to specify the attributes of a handler such as +.Dv INTR_MPSAFE . +.Fn sinthand_add +returns a pointer to a +.Li struct intrhand +which is used later to schedule the handler to run. +.Pp +The +.Fn sched_swi +function is used to schedule an interrupt handler and its associated thread to +run. +The +.Fa handler +argument specifies which software interrupt handler should be scheduled to run. +The +.Fa flags +argument specifies how and when the handler should be run and is a mask of one +or more of the following flags: +.Bl -tag -width SWI_NOSWITCH +.It Dv SWI_SWITCH +Specifies that the kernel should schedule the software interrupt thread +associated with the specified handler to run. If lightweight context switches +are in place, then the kernel will switch to this thread and run it +immediately. +.It Dv SWI_NOSWITCH +Specifies that the kernel should schedule the software interrupt thread +associated with the specified handler to run, but it should not attempt to +switch to the thread immediately. +.It Dv SWI_DELAY +Specifies that the kernel should mark the specified handler as needing to run, +but the kernel should not schedule the software interrupt thread to run. +Instead, +.Fa handler +will be executed the next time that the software interrupt thread runs after +being scheduled by another event. +Attaching a handler to the clock software interrupt thread and using this flag +when scheduling a software interrupt handler can be used to implement the +functionality previously performed by +.Fn setdelayed . +.El +.Pp +The +.Va tty_ithd +and +.Va clk_ithd +variables contain pointers to the software interrupt threads for the tty and +clock software interrupts, respectively. +.Va tty_ithd +is used to hang tty software interrupt handlers off of the same thread. +.Va clk_ithd +is used to hang delayed handlers off of the clock software interrupt thread so +that the functionality of +.Fn setdelayed +can be obtained in conjuction with +.Dv SWI_DELAY . +The +.Va net_ih , +.Va softclock_ih , +and +.Va vm_ih +handler cookies are used to schedule software interrupt threads to run for the +networking stack, clock interrupt, and VM subsystem respectively. +.Sh RETURN VALUES +The +.Fn sinthand_add +function returns a pointer to the newly created +.Li struct intrhand +if successful or +.Dv NULL +on error. +.Sh SEE ALSO +.Xr taskqueue 9 +.Sh HISTORY +The +.Fn sinthand_add +and the +.Fn sched_swi +functions first appeared in +.Fx 5.0 . +.Sh BUGS +The +.Fn sinthand_add +function currently doesn't check for or allow for the +.Dv INTR_EXCL +flag to be used to allow a software interrupt handler to have exclusive +access to a particular software interrupt thread. +There is also no checking to verify that one does not add a software interrupt +handler to a hardware interrupt thread. +.Pp +The +.Fn sinthand_add +function should really return an error code and use a +.Fa "void **cookiep" +argument to return a cookie that is passed in as the first argument to +.Fn sched_swi +instead of exposing the +.Li struct intrhand +type. +.Pp +Most of the global variables described in this manual page should not be +global, or at the very least should not be declared in +.Aq Pa sys/interrupt.h .
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