* Thread::scheduler_lock protects thread state, priority, etc.
* sThreadCreationLock protects thread creation and removal and list of
threads in team.
* Team::signal_lock and Team::time_lock protect list of threads in team
as well.
* Scheduler uses its own internal locking.
* The UNMAP command is theoretically much faster, as it can get many block
ranges instead of just a single range.
* Furthermore, the ATA TRIM command resembles it much better.
* Therefore, fs_trim_data now gets an array of ranges, and we use SCSI UNMAP
to trim.
* Updated BFS code to collect array ranges to fully support the new
fs_trim_data possibilities.
* No need for the atomically changed variables to be declared as
volatile.
* Drop support for atomically getting and setting unaligned data.
* Introduce atomic_get_and_set[64]() which works the same as
atomic_set[64]() used to. atomic_set[64]() does not return the
previous value anymore.
The new functions are meant to replace many uses of find_directory():
* find_paths() is supposed to be used when the directories of a certain
kind in all installation directories are needed (e.g. font
directories, add-on directory, etc.). Using this API makes code
robust wrt addition or removal of installation locations.
* find_path() is supposed to be used when files/directories associated
with a loaded program, library, or add-on need to be found (e.g. data
files or global settings).
* find_path_for_path() is similar to find_path(), but it starts from a
given path instead of an image.
The flag main purpose is to avoid race conditions between event handler
and cancel_timer(). However, cancel_timer() is safe even without
using gSchedulerLock.
If the event is scheduled to happen on other CPU than the CPU that
invokes cancel_timer() then cancel_timer() either disables the event
before its handler starts executing or waits until the event handler
is done.
If the event is scheduled on the same CPU that calls cancel_timer()
then, since cancel_timer() disables interrupts, the event is either
executed before cancel_timer() or when the timer interrupt handler
starts running the event is already disabled.
* Replace ports list mutex with R/W-lock.
* Move team port list protection to separate array of mutexes.
Relieve contention on sPortsLock by removing Team::port_list from its
protected items. With this, set_port_owner() only needs to acquire the
sPortsLock for reading.
* Add another hash table holding the ports by name. Used by find_port()
so it doesn't have to iterate over the list anymore.
* Use slab-based memory allocator for port messages. sPortQuotaLock was
acquired on every message send or receive and was thus another point
of contention. The lock is not necessary anymore.
* Lock for port hashes and Port::lock are no longer locked in a nested
fashion to reduce chances of blocking other threads.
* Make operations concurrency-safe by adding an atomically accessed
Port::state which provides linearization points to port creation and
deletion. Both operations are now divided into logical and physical
parts, the logical part just updating the state and the physical part
adding/remove it to/from the port hash and team port list.
* set_port_owner() is the only remaining function which still locks
Port::lock and one or two of sTeamListLock[] in a nested fashion.
Since it needs to move the port from one team list to another and
change Port::owner, there's no way around.
* Ports are now reference counted to make accesses to already-deleted
ports safe.
* Should fix #8007.
When removing a string attribute, decrement the referenced string's
usage count in the string cache. This fixes the potentially incorrect
usage counts in update mode. Not a serious problem, but it could lead
to only singly (or no longer) used strings to be written to the string
subsection instead of encoding them inline and thus to slightly greater
file sizes.
When joining with a single range, firstRange would be the same as
RangeAt(endIndex - 1) and we would overwrite its offset field before
getting its end offset, thus possibly resulting in a wrong joined range
size.
Simple scheduler behaves exactly the same as affine scheduler with a
single core. Obviously, affine scheduler is more complicated thus
introduces greater overhead but quite a lot of multicore logic has been
disabled on single core systems in the previous commit.
The method is supposed to return B_OK as long as the _result object has
been initialized, even if committing the transaction failed. Fixes the
unhelpful error messages of pkgman when committing the transaction
failed for some reason.
Update BKeymap::GetModifiedCharacters() to translate a given character
and set of modifiers filling out a list of all characters that match for another
set of modifiers.
This allows us to, for example, get all characters in the normal map that
have the '+' character in the corresponding shift map.
It is fully generic allowing one to get a list of characters in any map given
a character and modifiers of another map.
Also I converted from using a BList to using a BObjectList.
With this, along with BWindow::HasShortcut(), the semantic shortcuts now
work not only with Command+'=', but any key in the normal map that has
'+' in it's shift map as long as it isn't already taken by another shortcut.
This method fills out the passed-in BList of modified utf-8 characters for
a given utf-8 character and set of modifiers.
For example if you pass in "=" and B_SHIFT_KEY the list will get filled
out with each character in the shift map that has "=" in the normal map.
Each supported keymap modifier combination is available.
The reason this is useful will soon become apparent.
A BList is used because the character might be mapped multiple times,
for example if you have a Mac keyboard you've got two "=" keys, one in
0x1d and one in 0x6a.
The caller is responsible for creating the BList and destroying it as well as
freeing the resulting character strings.
This builds off of hrev46243 adding add-on directories all in one place
in AddOnMonitorHandler instead of repeating the code 3 times in
IndexServer, AddOnManager, and MediaAddOnServer.
The safe mode checking in InputServer is now redundant since it all
gets funneled into AddOnMonitorHandler::AddAddOnDirectories()
and the safe mode flags are checked there.
We should probably remove the InputServer::SafeMode() method, but,
I didn't want to break anything that depended on it so I left it.
There is a global heap of cores, where the key is the highest priority
of threads running on that core. Moreover, for each core there is
a heap of logical processors on this core where the key is the priority
of currently running thread.
The per-core heap is used for load balancing among logical processors
on that core. The global heap is used in initial decision where to put
the thread (note that the algorithm that makes this decision is not
complete yet).
Simple scheduler is used when we do not have to worry about cache affinity
(i.e. single core with or without SMT, multicore with all cache levels
shared).
When we replace gSchedulerLock with more fine grained locking affine
scheduler should also be chosen when logical CPU count is high (regardless
of cache).
In SMP systems simple scheduler will be used only when all logical
processors share all levels of cache and the number of CPUs is low.
In such systems we do not have to care about cache affinity and
the contention on the lock protecting shared run queue is low. Single
run queue makes load balancing very simple.
Kernel support for yielding to all (including lower priority) threads
has been removed. POSIX sched_yield() remains unchanged.
If a thread really needs to yield to everyone it can reduce its priority
to the lowest possible and then yield (it will then need to manually
return to its prvious priority upon continuing).
