Date: Wed, 28 Jan 2009 19:58:05 +0000 (UTC) From: Ed Schouten <ed@FreeBSD.org> To: cvs-src-old@freebsd.org Subject: cvs commit: src/sys/fs/devfs devfs_devs.c src/sys/kern kern_jail.c kern_mib.c kern_sysctl.c Message-ID: <200901281958.n0SJwiEs097767@repoman.freebsd.org>
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ed 2009-01-28 19:58:05 UTC
FreeBSD src repository
Modified files:
sys/fs/devfs devfs_devs.c
sys/kern kern_jail.c kern_mib.c kern_sysctl.c
Log:
SVN rev 187864 on 2009-01-28 19:58:05Z by ed
Mark most often used sysctl's as MPSAFE.
After running a `make buildkernel', I noticed most of the Giant locks in
sysctl are only caused by a very small amount of sysctl's:
- sysctl.name2oid. This one is locked by SYSCTL_LOCK, just like
sysctl.oidfmt.
- kern.ident, kern.osrelease, kern.version, etc. These are just constant
strings.
- kern.arandom, used by the stack protector. It is already protected by
arc4_mtx.
I also saw the following sysctl's show up. Not as often as the ones
above, but still quite often:
- security.jail.jailed. Also mark security.jail.list as MPSAFE. They
don't need locking or already use allprison_lock.
- kern.devname, used by devname(3), ttyname(3), etc.
This seems to reduce Giant locking inside sysctl by ~75% in my primitive
test setup.
Revision Changes Path
1.56 +3 -2 src/sys/fs/devfs/devfs_devs.c
1.93 +6 -4 src/sys/kern/kern_jail.c
1.93 +8 -7 src/sys/kern/kern_mib.c
1.187 +4 -3 src/sys/kern/kern_sysctl.c
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