docs/105997: sys/kern/sys_pipe.c refer to tuning(7), but there is no information about kern.ipc.maxpipekva in tuning(7)

[Beat Gaetzi]

>Number:         105997
>Category:       docs
>Synopsis:       sys/kern/sys_pipe.c refer to tuning(7), but there is no information about kern.ipc.maxpipekva in tuning(7)
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-doc
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          doc-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Nov 29 10:20:12 GMT 2006
>Closed-Date:
>Last-Modified:
>Originator:     Beat Gätzi
>Release:        FreeBSD 6.2-RC1 i386
>Organization:
>Environment:
System: FreeBSD daedalus.network.local 6.2-RC1 FreeBSD 6.2-RC1 #0: Sun Nov 19 19:23:21 CET 2006 beat at daedalus.network.local:/usr/obj/usr/src/sys/BEASTIE i386


	
>Description:
	In sys/kern/sys_pipe.c there is a refer to tuning(7):
		printf("kern.ipc.maxpipekva exceeded; see tuning(7)\n");
	But in share/man/man7/tuning.7 there is no information about this sysctl MIB.
>How-To-Repeat:
	
>Fix:
	- Remove reference to tuning(7) from sys_pipe.c
	or
	- Add a paragraph about kern.ipc.maxpipekva to tuning.7. I found some information
	  about this sysctl MIB in the comments of sys_pipe.c, but I'm not sure if this is
	  usefull:

	 * kern.ipc.maxpipekva - This is a hard limit on the amount of pageable
	 * address space available to us in pipe_map. This value is normally
	 * autotuned, but may also be loader tuned.
	 *
	 * kern.ipc.pipekva - This read-only sysctl tracks the current amount of
	 * memory in use by pipes.
	 *
	 * Based on how large pipekva is relative to maxpipekva, the following
	 * will happen:
	 *
	 * 0% - 50%:
	 *     New pipes are given 16K of memory backing, pipes may dynamically
	 *     grow to as large as 64K where needed.
	 * 50% - 75%:
	 *     New pipes are given 4K (or PAGE_SIZE) of memory backing,
	 *     existing pipes may NOT grow.
	 * 75% - 100%:
	 *     New pipes are given 4K (or PAGE_SIZE) of memory backing,
	 *     existing pipes will be shrunk down to 4K whenever possible.
	


>Release-Note:
>Audit-Trail:
>Unformatted: