freebsd-skq/sys/sparc64
attilio 16c7563cf4 The soft and hard busy mechanism rely on the vm object lock to work.
Unify the 2 concept into a real, minimal, sxlock where the shared
acquisition represent the soft busy and the exclusive acquisition
represent the hard busy.
The old VPO_WANTED mechanism becames the hard-path for this new lock
and it becomes per-page rather than per-object.
The vm_object lock becames an interlock for this functionality:
it can be held in both read or write mode.
However, if the vm_object lock is held in read mode while acquiring
or releasing the busy state, the thread owner cannot make any
assumption on the busy state unless it is also busying it.

Also:
- Add a new flag to directly shared busy pages while vm_page_alloc
  and vm_page_grab are being executed.  This will be very helpful
  once these functions happen under a read object lock.
- Move the swapping sleep into its own per-object flag

The KPI is heavilly changed this is why the version is bumped.
It is very likely that some VM ports users will need to change
their own code.

Sponsored by:	EMC / Isilon storage division
Discussed with:	alc
Reviewed by:	jeff, kib
Tested by:	gavin, bapt (older version)
Tested by:	pho, scottl
2013-08-09 11:11:11 +00:00
..
central
conf follow up to r254051 2013-08-09 08:11:09 +00:00
ebus
fhc
include Add MD (for now) atomic_store_acq_<type>() and use it in pmap_activate() 2013-08-06 15:34:11 +00:00
isa
pci Fix low-level uart drivers that set their fifo sizes in the softc too late. 2013-04-01 00:44:20 +00:00
sbus - Revert the part of r247601 which turned the overtemperature and power fail 2013-03-02 13:08:13 +00:00
sparc64 The soft and hard busy mechanism rely on the vm object lock to work. 2013-08-09 11:11:11 +00:00