Konstantin Belousov 2a339d9e3d Add implementation of robust mutexes, hopefully close enough to the ... intention of the POSIX IEEE Std 1003.1TM-2008/Cor 1-2013. A robust mutex is guaranteed to be cleared by the system upon either thread or process owner termination while the mutex is held. The next mutex locker is then notified about inconsistent mutex state and can execute (or abandon) corrective actions. The patch mostly consists of small changes here and there, adding neccessary checks for the inconsistent and abandoned conditions into existing paths. Additionally, the thread exit handler was extended to iterate over the userspace-maintained list of owned robust mutexes, unlocking and marking as terminated each of them. The list of owned robust mutexes cannot be maintained atomically synchronous with the mutex lock state (it is possible in kernel, but is too expensive). Instead, for the duration of lock or unlock operation, the current mutex is remembered in a special slot that is also checked by the kernel at thread termination. Kernel must be aware about the per-thread location of the heads of robust mutex lists and the current active mutex slot. When a thread touches a robust mutex for the first time, a new umtx op syscall is issued which informs about location of lists heads. The umtx sleep queues for PP and PI mutexes are split between non-robust and robust. Somewhat unrelated changes in the patch: 1. Style. 2. The fix for proper tdfind() call use in umtxq_sleep_pi() for shared pi mutexes. 3. Removal of the userspace struct pthread_mutex m_owner field. 4. The sysctl kern.ipc.umtx_vnode_persistent is added, which controls the lifetime of the shared mutex associated with a vnode' page. Reviewed by: jilles (previous version, supposedly the objection was fixed) Discussed with: brooks, Martin Simmons <martin@lispworks.com> (some aspects) Tested by: pho Sponsored by: The FreeBSD Foundation		2016-05-17 09:56:22 +00:00
..
cloudabi	Add implementation of robust mutexes, hopefully close enough to the	2016-05-17 09:56:22 +00:00
cloudabi64	Make CloudABI's way of doing TLS more friendly to userspace emulators.	2016-04-06 11:11:31 +00:00
freebsd32	The sendfile(2) allows to send extra data from userspace before the file	2016-03-29 19:57:11 +00:00
ia32	Implement vsyscall hack. Prior to 2.13 glibc uses vsyscall	2016-01-09 20:18:53 +00:00
linprocfs	linprocfs_doproclimits: Initialize error return before use	2016-04-20 01:03:06 +00:00
linsysfs	Add support to the jail framework to be able to mount linsysfs(5) and	2015-07-19 08:52:35 +00:00
linux	Add implementation of robust mutexes, hopefully close enough to the	2016-05-17 09:56:22 +00:00
linuxkpi/common	Only lock Giant when needed in the LinuxKPI.	2016-05-16 17:41:25 +00:00
ndis	ndis: spelling fixes in comments.	2016-04-30 00:35:46 +00:00
netbsd
svr4	Allow to build svr4 module with SYSV support separatelly from the kernel build.	2016-04-23 20:31:18 +00:00
x86bios	x86bios: spelling fix in a comment.	2016-04-30 00:34:04 +00:00