i386/137975: Not clearing of memory after file deletion from a ram-disk

[Mihail Konuhov]

>Number:         137975
>Category:       i386
>Synopsis:       Not clearing of memory after file deletion from a ram-disk
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-i386
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Aug 19 20:10:01 UTC 2009
>Closed-Date:
>Last-Modified:
>Originator:     Mihail Konuhov
>Release:        FreeBSD 7.2-RELEASE
>Organization:
hidden
>Environment:
FreeBSD hosting2 7.2-RELEASE FreeBSD 7.2-RELEASE #0: Fri Aug 14 23:42:05 MSD 2009     root at hosting2.localdomain:/usr/obj/usr/src/sys/myconf  i386
>Description:
Hello, all!
Excuse for my bad English...
I use ram-disks created by means of the utility "mdconfig". I have a problem with clearing of the RAM occupied with a ram-disk after removal of all files from it. At first I create ram-disk, I format in ufs it and I create on it a file on the size close to the ram-disk size. Then I delete a file both I check a memory state and I see that all memory was liberated not. Memory clearing occurs only after a ram-disk blackout.


------- other --------
system information:
make.conf:
PERL_VERSION=5.8.9
KERNCONF=myconf

myconf:
GENERIC options and devices and:

options         IPFIREWALL
options         IPFIREWALL_VERBOSE
options         IPFIREWALL_VERBOSE_LIMIT=0
options         IPFIREWALL_DEFAULT_TO_ACCEPT
options         IPDIVERT
options         IPFIREWALL_FORWARD
device          vlan



>How-To-Repeat:
This problem appears at performance of following operations:

--- Free Memory: 1934M, Free swap: 500M

# mdconfig -a -t swap -s 1024m -u 501
# newfs -m 0 -U md501
# mount /dev/md501 /home/0/run
# dd if=/dev/zero of=/home/0/run/test bs=1024 count=943718
# rm /home/0/run/test

--- Free Memory: 1003M, Free swap: 500M

# umount /home/0/run/
# mdconfig -d -u 501

--- Free Memory: 1925M, Free swap: 500M
>Fix:
I do not know solution of this problem

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