kmem leak in tmpmfs?
gcr+freebsd-stable at tharned.org
Mon May 29 10:50:53 PDT 2006
On Mon, 29 May 2006, Ulrich Spoerlein wrote:
> Greg Rivers wrote:
>> On Thursday 25 May 2006 19:43, Paul Allen wrote:
>>>> From Jonathan Noack <noackjr at alumni.rice.edu>, Thu, May 25, 2006 at
>>>> 07:56:07PM -0400: I am currently running with the following in
>>>> /etc/rc.conf and haven't experienced any problems:
>>>> tmpmfs_flags="-S -o async"
>>> Is there a way to accomplish this with an fstab entry?
>>> md /tmp mfs rw,async,-s1024m,-S
>>> no,I don't think so. But surely it would be better to just fixup the
>>> standard mount -t path to not call mount_mfs...
>> Actually there is a way. I too have not been satisfied with the tmpmfs
>> features in rc, so for some time now I've simply created a hard link:
>> cd /sbin && ln -f mdmfs mount_md
>> and then used an entry like this in /etc/fstab:
>> md /tmp md rw,async,-Sp1777,-s768M 0 0
>> This works great for me. A simple patch to mtree could make this hard link
>> part of the base system. Nothing else is needed.
> You should use the 'mfs' file system. This works out of the box:
> md /tmp mfs rw,-s256m,-S,-Otime,async,noatime 0 0
> Ulrich Spoerlein
Using 'mfs' as you suggest doesn't work; you'll only get a usage message
when you try to mount:
usage: mount_mfs -C [-lNU] [-a maxcontig] [-b block-size] [-c cylinders]
[-d rotdelay] [-e maxbpg] [-F file] [-f frag-size] [-i bytes]
[-m percent-free] [-n rotational-positions] [-O optimization]
[-o mount-options] [-s size] [-v version] md-device mount-point
This is because not all mdmfs options are available in "mount_mfs
compatibility" mode as described at the bottom of mdmfs(8).
Conspicuously absent are -p, -S, and -w. With 'mfs', you can't turn off
softupdates (ie. can't have async), and you can't set arbitrary modes and
ownerships on the file system. Creating the "mount_md" hard link to mdmfs
and using type 'md' in fstab allows you to use all the features of mdmfs.
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