freebsd-dev/sys/compat
Attilio Rao 89f6b8632c Switch the vm_object mutex to be a rwlock. This will enable in the
future further optimizations where the vm_object lock will be held
in read mode most of the time the page cache resident pool of pages
are accessed for reading purposes.

The change is mostly mechanical but few notes are reported:
* The KPI changes as follow:
  - VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK()
  - VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK()
  - VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK()
  - VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED()
    (in order to avoid visibility of implementation details)
  - The read-mode operations are added:
    VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(),
    VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED()
* The vm/vm_pager.h namespace pollution avoidance (forcing requiring
  sys/mutex.h in consumers directly to cater its inlining functions
  using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h
  consumers now must include also sys/rwlock.h.
* zfs requires a quite convoluted fix to include FreeBSD rwlocks into
  the compat layer because the name clash between FreeBSD and solaris
  versions must be avoided.
  At this purpose zfs redefines the vm_object locking functions
  directly, isolating the FreeBSD components in specific compat stubs.

The KPI results heavilly broken by this commit.  Thirdy part ports must
be updated accordingly (I can think off-hand of VirtualBox, for example).

Sponsored by:	EMC / Isilon storage division
Reviewed by:	jeff
Reviewed by:	pjd (ZFS specific review)
Discussed with:	alc
Tested by:	pho
2013-03-09 02:32:23 +00:00
..
freebsd32 Regen after r247667. 2013-03-02 21:12:54 +00:00
ia32 Cosmetics: define FREEBSD32_MINUSER and AOUT32_MINUSER for struct 2012-07-22 13:41:45 +00:00
linprocfs Switch the vm_object mutex to be a rwlock. This will enable in the 2013-03-09 02:32:23 +00:00
linsysfs Add procfs to jail-mountable filesystems. 2012-02-29 00:30:18 +00:00
linux Remove check for NULL prior to free(9) and m_freem(9). 2013-03-04 02:21:34 +00:00
ndis Fix wrong assignment. 2013-03-01 23:21:18 +00:00
netbsd Remove some more NetBSD compat shims and other unused bits from these 2012-09-10 18:49:49 +00:00
svr4 Merge Capsicum overhaul: 2013-03-02 00:53:12 +00:00
x86bios Mark all SYSCTL_NODEs static that have no corresponding SYSCTL_DECLs. 2011-11-07 15:43:11 +00:00