Attilio Rao 047dd67e96 Optimize lockmgr in order to get rid of the pool mutex interlock, of the ... state transitioning flags and of msleep(9) callings. Use, instead, an algorithm very similar to what sx(9) and rwlock(9) alredy do and direct accesses to the sleepqueue(9) primitive. In order to avoid writer starvation a mechanism very similar to what rwlock(9) uses now is implemented, with the correspective per-thread shared lockmgrs counter. This patch also adds 2 new functions to lockmgr KPI: lockmgr_rw() and lockmgr_args_rw(). These two are like the 2 "normal" versions, but they both accept a rwlock as interlock. In order to realize this, the general lockmgr manager function "__lockmgr_args()" has been implemented through the generic lock layer. It supports all the blocking primitives, but currently only these 2 mappers live. The patch drops the support for WITNESS atm, but it will be probabilly added soon. Also, there is a little race in the draining code which is also present in the current CVS stock implementation: if some sharers, once they wakeup, are in the runqueue they can contend the lock with the exclusive drainer. This is hard to be fixed but the now committed code mitigate this issue a lot better than the (past) CVS version. In addition assertive KA_HELD and KA_UNHELD have been made mute assertions because they are dangerous and they will be nomore supported soon. In order to avoid namespace pollution, stack.h is splitted into two parts: one which includes only the "struct stack" definition (_stack.h) and one defining the KPI. In this way, newly added _lockmgr.h can just include _stack.h. Kernel ABI results heavilly changed by this commit (the now committed version of "struct lock" is a lot smaller than the previous one) and KPI results broken by lockmgr_rw() / lockmgr_args_rw() introduction, so manpages and __FreeBSD_version will be updated accordingly. Tested by: kris, pho, jeff, danger Reviewed by: jeff Sponsored by: Google, Summer of Code program 2007		2008-04-06 20:08:51 +00:00
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cd9660	Cleanup lockmgr interface and exported KPI:	2008-01-24 12:34:30 +00:00
coda	Add the support for the AT_FDCWD and fd-relative name lookups to the	2008-03-31 12:01:21 +00:00
deadfs	Below is slightly edited description of the LOR by Tor Egge:	2007-01-22 11:25:22 +00:00
devfs	Do not dereference cdev->si_cdevsw, use the dev_refthread() to properly	2008-03-20 16:08:42 +00:00
fdescfs	The temporary workaround for the call to the vget() without lock type in	2008-04-04 09:37:57 +00:00
fifofs	Remove kernel support for M:N threading.	2008-03-12 10:12:01 +00:00
hpfs	Cleanup lockmgr interface and exported KPI:	2008-01-24 12:34:30 +00:00
msdosfs	Add the support for the AT_FDCWD and fd-relative name lookups to the	2008-03-31 12:01:21 +00:00
ntfs	Fix a lock leak in the ntfs locking scheme:	2008-02-13 13:02:12 +00:00
nullfs	Add the support for the AT_FDCWD and fd-relative name lookups to the	2008-03-31 12:01:21 +00:00
nwfs	Replace lockmgr lock protecting nwfs vnode hash table with an sx lock.	2008-03-02 19:02:30 +00:00
portalfs	vn_lock() is currently only used with the 'curthread' passed as argument.	2008-01-10 01:10:58 +00:00
procfs	Remove kernel support for M:N threading.	2008-03-12 10:12:01 +00:00
pseudofs	Introduce some functions in the vnode locks namespace and in the ffs	2008-02-24 16:38:58 +00:00
smbfs	Replace lockmgr lock protecting smbfs node hash table with sx lock.	2008-03-02 18:56:13 +00:00
tmpfs	Add the new kernel-mode NFS Lock Manager. To use it instead of the	2008-03-26 15:23:12 +00:00
udf	Cleanup lockmgr interface and exported KPI:	2008-01-24 12:34:30 +00:00
unionfs	Optimize lockmgr in order to get rid of the pool mutex interlock, of the	2008-04-06 20:08:51 +00:00