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Mark most often used sysctl's as MPSAFE.

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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.
This commit is contained in:
Ed Schouten 2009-01-28 19:58:05 +00:00
parent c4506e0298
commit f3b86a5fd7
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=187864
4 changed files with 21 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
sys/fs/devfs/devfs_devs.c
View File

@ -103,8 +103,9 @@ sysctl_devname(SYSCTL_HANDLER_ARGS)
return (error);
}
SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY,
NULL, 0, sysctl_devname, "", "devname(3) handler");
SYSCTL_PROC(_kern, OID_AUTO, devname,
CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY|CTLFLAG_MPSAFE,
NULL, 0, sysctl_devname, "", "devname(3) handler");
SYSCTL_INT(_debug_sizeof, OID_AUTO, cdev, CTLFLAG_RD,
0, sizeof(struct cdev), "sizeof(struct cdev)");

10
sys/kern/kern_jail.c
View File

@ -1529,8 +1529,9 @@ sysctl_jail_list(SYSCTL_HANDLER_ARGS)
return (error);
}
SYSCTL_OID(_security_jail, OID_AUTO, list, CTLTYPE_STRUCT | CTLFLAG_RD,
NULL, 0, sysctl_jail_list, "S", "List of active jails");
SYSCTL_OID(_security_jail, OID_AUTO, list,
CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
sysctl_jail_list, "S", "List of active jails");
static int
sysctl_jail_jailed(SYSCTL_HANDLER_ARGS)
@ -1542,8 +1543,9 @@ sysctl_jail_jailed(SYSCTL_HANDLER_ARGS)
return (error);
}
SYSCTL_PROC(_security_jail, OID_AUTO, jailed, CTLTYPE_INT | CTLFLAG_RD,
NULL, 0, sysctl_jail_jailed, "I", "Process in jail?");
SYSCTL_PROC(_security_jail, OID_AUTO, jailed,
CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
sysctl_jail_jailed, "I", "Process in jail?");
#ifdef DDB
DB_SHOW_COMMAND(jails, db_show_jails)

15
sys/kern/kern_mib.c
View File

@ -87,19 +87,19 @@ SYSCTL_NODE(, OID_AUTO, regression, CTLFLAG_RW, 0,
"Regression test MIB");
#endif
SYSCTL_STRING(_kern, OID_AUTO, ident, CTLFLAG_RD,
SYSCTL_STRING(_kern, OID_AUTO, ident, CTLFLAG_RD|CTLFLAG_MPSAFE,
kern_ident, 0, "Kernel identifier");
SYSCTL_STRING(_kern, KERN_OSRELEASE, osrelease, CTLFLAG_RD,
SYSCTL_STRING(_kern, KERN_OSRELEASE, osrelease, CTLFLAG_RD|CTLFLAG_MPSAFE,
osrelease, 0, "Operating system release");
SYSCTL_INT(_kern, KERN_OSREV, osrevision, CTLFLAG_RD,
0, BSD, "Operating system revision");
SYSCTL_STRING(_kern, KERN_VERSION, version, CTLFLAG_RD,
SYSCTL_STRING(_kern, KERN_VERSION, version, CTLFLAG_RD|CTLFLAG_MPSAFE,
version, 0, "Kernel version");
SYSCTL_STRING(_kern, KERN_OSTYPE, ostype, CTLFLAG_RD,
SYSCTL_STRING(_kern, KERN_OSTYPE, ostype, CTLFLAG_RD|CTLFLAG_MPSAFE,
ostype, 0, "Operating system type");
/*
@ -165,8 +165,9 @@ sysctl_kern_arnd(SYSCTL_HANDLER_ARGS)
return (SYSCTL_OUT(req, buf, len));
}
SYSCTL_PROC(_kern, KERN_ARND, arandom, CTLTYPE_OPAQUE | CTLFLAG_RD,
NULL, 0, sysctl_kern_arnd, "", "arc4rand");
SYSCTL_PROC(_kern, KERN_ARND, arandom,
CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
sysctl_kern_arnd, "", "arc4rand");
static int
sysctl_hw_physmem(SYSCTL_HANDLER_ARGS)
@ -267,7 +268,7 @@ sysctl_hostname(SYSCTL_HANDLER_ARGS)
}
SYSCTL_PROC(_kern, KERN_HOSTNAME, hostname,
CTLTYPE_STRING|CTLFLAG_RW|CTLFLAG_PRISON,
CTLTYPE_STRING|CTLFLAG_RW|CTLFLAG_PRISON|CTLFLAG_MPSAFE,
0, 0, sysctl_hostname, "A", "Hostname");
static int regression_securelevel_nonmonotonic = 0;

7
sys/kern/kern_sysctl.c
View File

@ -773,8 +773,8 @@ sysctl_sysctl_name2oid(SYSCTL_HANDLER_ARGS)
return (error);
}
SYSCTL_PROC(_sysctl, 3, name2oid, CTLFLAG_RW|CTLFLAG_ANYBODY, 0, 0,
sysctl_sysctl_name2oid, "I", "");
SYSCTL_PROC(_sysctl, 3, name2oid, CTLFLAG_RW|CTLFLAG_ANYBODY|CTLFLAG_MPSAFE,
0, 0, sysctl_sysctl_name2oid, "I", "");
static int
sysctl_sysctl_oidfmt(SYSCTL_HANDLER_ARGS)
@ -796,7 +796,8 @@ sysctl_sysctl_oidfmt(SYSCTL_HANDLER_ARGS)
}
static SYSCTL_NODE(_sysctl, 4, oidfmt, CTLFLAG_RD, sysctl_sysctl_oidfmt, "");
static SYSCTL_NODE(_sysctl, 4, oidfmt, CTLFLAG_RD|CTLFLAG_MPSAFE,
sysctl_sysctl_oidfmt, "");
static int
sysctl_sysctl_oiddescr(SYSCTL_HANDLER_ARGS)