Date: Mon, 14 Apr 1997 03:40:16 -0700 (PDT) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: freebsd-bugs Subject: Re: kern/3278: MFS chews up all swap space Message-ID: <199704141040.DAA02624@freefall.freebsd.org>
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The following reply was made to PR kern/3278; it has been noted by GNATS. From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: jlemon@americantv.com Cc: FreeBSD-gnats-submit@freebsd.org Subject: Re: kern/3278: MFS chews up all swap space Date: Mon, 14 Apr 1997 11:46:25 +0200 (MET DST) > >Environment: > > FreeBSD 3.0-CURRENT #0: Sun Apr 13 21:55:38 CDT 1997 > > Machine with 32M memory, 71M swap > > >Description: > > Mounting MFS filesystem causes roughly 2x physical memory to > be allocated in swap partition, even though almost nothing ... > update that ususally looks like: > > # grep swap /etc/fstab > /dev/sd3s2b none swap sw 0 0 > > # swapinfo > Device 1K-blocks Used Avail Capacity Type > /dev/sd3s2b 73728 0 73664 0% Interleaved > > # mount -t mfs /dev/sd3s2b /tmp hmmm... don't you have to specify the size of the file system you want to create ? Otherwise the code tries to infer the size from the info it has available (swap partition size, or some other thing). This works perfectly for me: mount -t mfs -o "-s 20480" /dev/wd0s1b /tmp/aa BTW the manpage for mount_mfs contains a mistake in the EXAMPLES section, the size must be specified without the equal sign WRONG: mount_mfs -s=20480 -o nosuid,nodev /dev/sd0b /tmp RIGHT: mount_mfs -s 20480 -o nosuid,nodev /dev/sd0b /tmp If one really wants to make things smoother, probably newfs.c should be modified (around line 431) so that the default value for mfs file systems is just a fraction (say 1/3 .. 1/2) of the partition size (that's a default so it can be easily overridden). As an example (in pseudo diff -u): newfs.c from 2.2.1-RELEASE, line 431: if (fssize == 0) - fssize = pp->p_size; + fssize = mfs ? pp->p_size / 2 : pp->p_size ; if (fssize > pp->p_size && !mfs) Cheers Luigi -----------------------------+-------------------------------------- Luigi Rizzo | Dip. di Ingegneria dell'Informazione email: luigi@iet.unipi.it | Universita' di Pisa tel: +39-50-568533 | via Diotisalvi 2, 56126 PISA (Italy) fax: +39-50-568522 | http://www.iet.unipi.it/~luigi/ _____________________________|______________________________________
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