kern/156658: sysctl vm.idlezero_enable=1 causes hangup.

[KOIE Hidetaka]

>Number:         156658
>Category:       kern
>Synopsis:       sysctl vm.idlezero_enable=1 causes hangup.
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Apr 26 08:30:05 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator:     KOIE Hidetaka
>Release:        9.0-CURRENT
>Organization:
surigiken
>Environment:
FreeBSD freebsd.suri.co.jp 9.0-CURRENT FreeBSD 9.0-CURRENT #6: Tue Apr 26 16:14:09 JST 2011     koie at freebsd.suri.co.jp:/usr/obj/usr/src/sys/GENERIC  amd64
>Description:
After sysctl vm.idlezero_enable=1,
many processes wait for [*vm page queue free mutex] and don't respond.

It seems that the vm_pagezero() thread loops in vm_phys_zero_pages_idle() forever with mtx_lock(&vm_page_queue_free_mtx).

>How-To-Repeat:
sysctl vm.idlezero_enable=1
find / -type f -print | xargs grep -l hogehogehoge

>Fix:


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