History log of /haiku/src/system/kernel/vm/VMCache.cpp
Revision Date Author Comments
# 425ac1b6 20-Jun-2023 Alexander von Gluck IV <kallisti5@unixzen.com>

refactor: Swap %Ld for %lld in all format usages

* %Ld is an undocumented alias for %lld in glibc.
* muslc doesn't implement it for this reason.
* While we will likely never drop %Ld support,
lets clean house and set a better example.

Change-Id: Id46dad3104abae483e80cc5c05d1464d3ecd8030
Reviewed-on: https://review.haiku-os.org/c/haiku/+/6636
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>
Reviewed-by: Alex von Gluck IV <kallisti5@unixzen.com>
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>


# 484bf053 26-Apr-2023 Augustin Cavalier <waddlesplash@gmail.com>

VMCache: Use THREAD_BLOCK_TYPE_OTHER_OBJECT.

This would have assisted in debugging #18390.


# 850fc02f 13-Jun-2022 Augustin Cavalier <waddlesplash@gmail.com>

kernel/vm: Specifiy the page as the object being waited on in VMCache.

I got a strange whole-system hang in file_cache_resize into this
function. Possibly the page was spuriously busy, perhaps it wasn't,
but not having function arguments on x86_64 in stack traces, I was
unable to deduce what page was actually being waited on.

In case it happens again, this should allow it to be debugged further
by placing the address of the vm_page structure in the thread wait
informations. (A string is not very useful here anyway.)


# 36a1e12f 07-Dec-2021 Augustin Cavalier <waddlesplash@gmail.com>

kernel/vm: Cast temporary to uint32.

It is defined as a uint32:1, which apparently becomes an "int" on
newer GCC versions, which thus triggers a -Werror=format. So,
convert it explicitly in order to prevent the error.


# 6425e173 01-Sep-2021 Augustin Cavalier <waddlesplash@gmail.com>

Add more missing headers following previous commits.

These also are only a problem on riscv64; I guess thread.h
must not be included in some arch header there.


# 8e74e307 29-May-2020 Michael Lotz <mmlr@mlotz.ch>

kernel/vm: Add discard_address_range that discards pages.

Pages in the given range are unmapped and freed without getting written
back anywhere. It can be used whenever a caller does not care about the
data in the given range anymore and wants to reduce page pressure.

Change-Id: I8bcce68fab278efef710d3714677e1d463504a56
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2843
Reviewed-by: waddlesplash <waddlesplash@gmail.com>


# 146630e0 12-Jun-2020 Michael Lotz <mmlr@mlotz.ch>

kernel/vm: Fix build with swap support disabled.

The rename of the system_info members was missed in
d02aaee17e007631fcfa91a012ec7b6386927012 (part of the scheduler branch
merge of hrev46690). The unguarded object_cache was introduced even
earlier as part of hrev43133.


# 428bc69a 22-May-2020 Michael Lotz <mmlr@mlotz.ch>

VMCache: Factor out a _FreePageRange method.

The code in the Resize and Rebase methods was identical except for the
iterator.

Change-Id: I9f6b3c2c09af0c26778215bd627fed030c4d46f1
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2835
Reviewed-by: waddlesplash <waddlesplash@gmail.com>


# 4e2b49bc 04-May-2020 Michael Lotz <mmlr@mlotz.ch>

kernel/vm: Implement swap adoption for cut_area middle case.

Rename MovePageRange to Adopt and group it with Resize/Rebase as it
covers the third, middle cut case.

Implement VMAnonymousCache::Adopt() to actually adopt swap pages. This
has to recreate swap blocks instead of taking them over from the source
cache as the cut offset or base offset between the caches may not be
swap block aligned. This means that adoption may fail due to memory
shortage in allocating the swap blocks.

For the middle cut case it is therefore now possible to have the adopt
fail in which case the previous cache restore logic is applied. Since
the readoption of the pages from the second cache can fail for the same
reason, there is a slight chance that we can't restore and lose pages.
For now, just panic in such a case and add a TODO to free memory and
retry.

Change-Id: I9a661f00c8f03bbbea2fe6dee90371c68d7951e6
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2588
Reviewed-by: waddlesplash <waddlesplash@gmail.com>


# c6657ffe 15-Apr-2012 Hamish Morrison <hamish@lavabit.com>

Resize caches in all cases when cutting areas

* Adds VMCache::MovePageRange() and VMCache::Rebase() to facilitate
this.

Applied on top of hrev45098 and rebased with the hrev45564 page_num_t to
off_t change included.

Change-Id: Ie61bf43696783e3376fb4144ddced3781aa092ba
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2581
Reviewed-by: waddlesplash <waddlesplash@gmail.com>


# 271ac910 09-Jan-2015 Adrien Destugues <pulkomandy@gmail.com>

Remove useless includes of khash.h

* These files were already converted to BOpenHashTable.
* For #9552.


# dac7b7c9 06-Dec-2013 Ingo Weinhold <ingo_weinhold@gmx.de>

Fix various 64 bit related warnings

Mostly printf() format strings and signed-unsigned comparisons.
Fixes the x86_64 build.


# c8dd9f77 29-Oct-2013 Pawel Dziepak <pdziepak@quarnos.org>

kernel: Add thread_unblock() and use it where possible


# eca34ad1 02-Dec-2012 Michael Lotz <mmlr@mlotz.ch>

Print page and cache using initial commands in panic message.


# 3d49fa31 09-Nov-2012 Ithamar R. Adema <ithamar@upgrade-android.com>

VMCache: Fix broken trace statements


# 11d35d1b 05-Jul-2012 Alex Smith <alex@alex-smith.me.uk>

Fixed tracing printf formats in VM code.


# 294711f9 27-Jun-2012 Alex Smith <alex@alex-smith.me.uk>

Changed {,u}int64 to be long rather than long long on x86_64.


# 4be4fc6b 15-Jun-2012 Alex Smith <alex@alex-smith.me.uk>

More 64-bit compilation/safety fixes.


# f8154d17 02-Nov-2011 Ingo Weinhold <ingo_weinhold@gmx.de>

mmlr (distracted) + bonefish:
* Turn VMCache::consumers C list into a DoublyLinkedList.
* Use object caches for the different VMCache types and the VMCacheRefs.
The purpose is to reduce slab area fragmentation.
* Requires the introduction of a pure virtual VMCache::DeleteObject()
method, implemented in the derived classes.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@43133 a95241bf-73f2-0310-859d-f6bbb57e9c96


# ebf63109 31-Oct-2011 Michael Lotz <mmlr@mlotz.ch>

Tiny style cleanup. No functional change.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@43044 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 24df6592 11-Jun-2011 Ingo Weinhold <ingo_weinhold@gmx.de>

Merged signals-merge branch into trunk with the following changes:
* Reorganized the kernel locking related to threads and teams.
* We now discriminate correctly between process and thread signals. Signal
handlers have been moved to teams. Fixes #5679.
* Implemented real-time signal support, including signal queuing, SA_SIGINFO
support, sigqueue(), sigwaitinfo(), sigtimedwait(), waitid(), and the addition
of the real-time signal range. Closes #1935 and #2695.
* Gave SIGBUS a separate signal number. Fixes #6704.
* Implemented <time.h> clock and timer support, and fixed/completed alarm() and
[set]itimer(). Closes #5682.
* Implemented support for thread cancellation. Closes #5686.
* Moved send_signal() from <signal.h> to <OS.h>. Fixes #7554.
* Lots over smaller more or less related changes.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@42116 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 4535495d 10-Jan-2011 Ingo Weinhold <ingo_weinhold@gmx.de>

Merged the signals branch into trunk, with these changes:
* The team and thread kernel structures have been renamed to Team and Thread
respectively and moved into the new BKernel namespace.
* Several (kernel add-on) sources have been converted from C to C++ since
private kernel headers are included that are no longer C compatible.

Changes after merging:
* Fixed gcc 2 build (warnings mainly in the scary firewire bus manager).


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@40196 a95241bf-73f2-0310-859d-f6bbb57e9c96


# a0d93d14 02-Jan-2011 Ingo Weinhold <ingo_weinhold@gmx.de>

* VMCache::Unlock(): Renamed local variable consumerLocked to avoid shadowing
the parameter (CID 5329).
* _MergeWithOnlyConsumer(): Removed the somewhat weird consumerLocked
parameter. The caller can unlock itself, if desired. Improves Unlock()
readability.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@40084 a95241bf-73f2-0310-859d-f6bbb57e9c96


# b9447668 10-Jul-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* Moved the vm_page initialization from vm_page.cpp:vm_page_init() to the new
vm_page::Init().
* Made vm_page::wired_count private and added accessor methods.
* Added VMCache::fWiredPagesCount (the number of wired pages the cache
contains) and accessor methods.
* Made more use of vm_page::IsMapped().
* vm_copy_on_write_area(): Added vm_page_reservation* parameter that can be
used to request a special handling for wired pages. If given the wired pages
are replaced by copies and the original pages are moved to the upper cache.
* vm_copy_area():
- We don't need to do any wired ranges handling, if the source area is a
B_SHARED_AREA, since we don't touch the area's mappings in this case.
- We no longer wait for wired ranges of the concerned areas to disappear.
Instead we use the new vm_copy_on_write_area() feature and just let it
copy the wired pages. This fixes #6288, an issue introduced with the use
of user mutexes in libroot: When executing multiple concurrent fork()s all
but the first one would wait on the fork mutex, which (being a user mutex)
would wire a page that the vm_copy_area() of the first fork() would wait
for.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37460 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 13638944 21-Jun-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

Removed never read VMCache::scan_skip.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37195 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 377ecfe7 14-Jun-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* Renamed cache_type_to_string() to vm_cache_type_to_string() and made in
kernel private.
* Moved dumping code from dump_cache() to new VMCache::Dump().
* Override VMCache::Dump() in VMVnodeCache to also print the vnode.
* Removed no longer needed VMCache::GetLock().


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37138 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 1d578e15 02-Jun-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

Fixed more address types related issues. Mostly printf() or comparison
warnings, but also some oversights from earlier changes.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37000 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 435c43f5 02-Jun-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* Introduced type generic_io_vec, which is similar to iovec, but uses types
that are wide enough for both virtual and physical addresses.
* DMABuffer, IORequest, IOScheduler,... and code using them: Use
generic_io_vec and generic_{addr,size}_t where necessary.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@36997 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 6e83a6fa 20-Apr-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* VMCache::Resize(): Corrected TODO comment.
* Changed the semantics of VMCache::HasPage(). It was interpreted
inconsistently by the derived classes. Now it returns whether the backing
store can provide the page (via Read()). The default implementation returns
false. VNodeCache::HasPage() only returns true, if the given offset is
within the cache (i.e. file) bounds. This prevents vm_soft_fault() from
adding clean pages to vnode caches on faults beyond the file bounds.
Probably fixes #5473 -- at least mmap_resize_test behaves correctly, now.
* Removed redundant HasPage() and Fault() overrides in VMCache derived
classes.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@36374 a95241bf-73f2-0310-859d-f6bbb57e9c96


# efeca209 20-Apr-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

Made VMCache::Resize() virtual and let VMAnonymousCache override it to free
swap space when the cache shrinks. Currently the implementation stil leaks
swap space of busy pages.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@36373 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 5f310d4d 13-Apr-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

Added TODO.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@36236 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 86875ad9 13-Apr-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

Added VMCache::DebugHasPage() and DebugLookupPage() for use in the kernel
debugger.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@36228 a95241bf-73f2-0310-859d-f6bbb57e9c96


# bd7645a1 20-Feb-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* Made vm_page::state private and added accessor methods.
* Added kernel tracing for page state transitions.



git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35538 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 40bb9481 03-Feb-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* Removed useless return parameter from vm_remove_all_page_mappings().
* Added vm_clear_page_mapping_accessed_flags() and
vm_remove_all_page_mappings_if_unaccessed(), which combine the functionality
of vm_test_map_activation(), vm_clear_map_flags(), and
vm_remove_all_page_mappings(), thus saving lots of calls to translation map
methods. The backend is the new method
VMTranslationMap::ClearAccessedAndModified().
* Started to make use of the cached page queue and changed the meaning of the
other non-free queues slightly:
- Active queue: Contains mapped pages that have been used recently.
- Inactive queue: Contains mapped pages that have not been used recently. Also
contains unmapped temporary pages.
- Modified queue: Contains unmapped modified pages.
- Cached queue: Contains unmapped unmodified pages (LRU sorted).
Unless we're actually low on memory and actively do paging, modified and
cached queues only contain non-temporary pages. Cached pages are considered
quasi free. They still belong to a cache, but since they are unmodified and
unmapped, they can be freed immediately. And this is what
vm_page_[try_]reserve_pages() do now when there are no more actually free
pages at hand. Essentially this means that pages storing cached file data,
unless mmap()ped, no longer are considered used and don't contribute to page
pressure. Paging will not happen as long there are enough free + cached pages
available.
* Reimplemented the page daemon. It no longer scans all pages, but instead works
the page queues. As long as the free pages situation is harmless, it only
iterates through the active queue and deactivates pages that have not been
used recently. When paging occurs it additionally scans the inactive queue and
frees pages that have not been used recently.
* Changed the page reservation/allocation interface:
vm_page_[try_]reserve_pages(), vm_page_unreserve_pages(), and
vm_page_allocate_page() now take a vm_page_reservation structure pointer.
The reservation functions initialize the structure -- currently consisting
only of a count member for the number of still reserved pages.
vm_page_allocate_page() decrements the count and vm_page_unreserve_pages()
unreserves the remaining pages (if any). Advantages are that reservation/
unreservation mismatches cannot occur anymore, that vm_page_allocate_page()
can verify that the caller has indeed a reserved page left, and that there's
no unnecessary pressure on the free page pool anymore. The only disadvantage
is that the vm_page_reservation object needs to be passed around a bit.
* Reworked the page reservation implementation:
- Got rid of sSystemReservedPages and sPageDeficit. Instead
sUnreservedFreePages now actually contains the number of free pages that
have not yet been reserved (it cannot become negative anymore) and the new
sUnsatisfiedPageReservations contains the number of pages that are still
needed for reservation.
- Threads waiting for reservations do now add themselves to a waiter queue,
which is ordered by descending priority (VM priority and thread priority).
High priority waiters are served first when pages become available.
Fixes #5328.
* cache_prefetch_vnode(): Would reserve one less page than allocated later, if
the size wasn't page aligned.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35393 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 72382fa6 29-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* Removed the page state PAGE_STATE_BUSY and instead introduced a vm_page::busy
flag. The obvious advantage is that one can still see what state a page is in
and even move it between states while being marked busy.
* Removed the vm_page::is_dummy flag. Instead we mark marker pages busy, which
in all cases has the same effect. Introduced a vm_page_is_dummy() that can
still check whether a given page is a dummy page.
* vm_page_unreserve_pages(): Before adding to the system reserve make sure
sUnreservedFreePages is non-negative. Otherwise we'd make nonexisting pages
available for allocation. steal_pages() still has the same problem and it
can't be solved that easily.
* map_page(): No longer changes the page state/mark the page unbusy. That's the
caller's responsibility.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35331 a95241bf-73f2-0310-859d-f6bbb57e9c96


# deee8524 26-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* Introduced {malloc,memalign,free}_etc() which take an additional "flags"
argument. They replace the previous special-purpose allocation functions
(malloc_nogrow(), vip_io_request_malloc()).
* Moved the I/O VIP heap to heap.cpp accordingly.
* Added quite a bit of passing around of allocation flags in the VM,
particularly in the VM*AddressSpace classes.
* Fixed IOBuffer::GetNextVirtualVec(): It was ignoring the VIP flag and always
allocated on the normal heap.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35316 a95241bf-73f2-0310-859d-f6bbb57e9c96


# cff6e9e4 26-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* The system now holds back a small reserve of committable memory and pages. The
memory and page reservation functions have a new "priority" parameter that
indicates how deep the function may tap into that reserve. The currently
existing priority levels are "user", "system", and "VIP". The idea is that
user programs should never be able to cause a state that gets the kernel into
trouble due to heavy battling for memory. The "VIP" level (not really used
yet) is intended for allocations that are required to free memory eventually
(in the page writer). More levels are thinkable in the future, like "user real
time" or "user system server".
* Added "priority" parameters to several VMCache methods.
* Replaced the map_backing_store() "unmapAddressRange" parameter by a "flags"
parameter.
* Added area creation flag CREATE_AREA_PRIORITY_VIP and slab allocator flag
CACHE_PRIORITY_VIP indicating the importance of the request.
* Changed most code to pass the right priorities/flags.

These changes already significantly improve the behavior in low memory
situations. I've tested a bit with 64 MB (virtual) RAM and, while not
particularly fast and responsive, the system remains at least usable under high
memory pressure.
As a side effect the slab allocator can now be used as general memory allocator.
Not done by default yet, though.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35295 a95241bf-73f2-0310-859d-f6bbb57e9c96


# ad6ad0f1 24-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

VMCache::Init(): Initialize the debug_* members before allocating the
VMCacheRef object, since that can fail, in which case the subsequently called
Delete() would use uninitialized pointers.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35279 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 6379e53e 19-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

vm_page no longer points directly to its containing cache, but rather to a
VMCacheRef object which points to the cache. This allows to optimize
VMCache::MoveAllPages(), since it no longer needs to iterate over all pages
to adjust their cache pointer. It can simple swap the cache refs of the two
caches instead.

Reduces the total -j8 Haiku image build time only marginally. The kernel time
drops almost 10%, though.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35155 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 3632eeed 18-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* VMCache: Added a UserData attribute which can be used by the lock holder.
* Added "bool consumerLocked" parameter to VMCache::Unlock() and
ReleaseRefAndUnlock(). Since Unlock() may cause the cache to be merged with
a consumer cache, the flag is needed to prevent a deadlock in case the
caller still holds a lock to the consumer. Hasn't been a problem yet, since
that situation never occurred.
* VMCacheChainLocker: Reversed unlocking order to bottom-up. The other
direction could cause a deadlock in case caches would be merged, since the
locking order would be reversed. The way VMCacheChainLocker was used this
didn't happen, though.
* fault_get_page(): While copying a page from a lower cache to the top cache,
we do now unlock all caches but the top one, so we don't unnecessarily
kill concurrency.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35153 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 31996a8e 08-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

Added TODO.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34964 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 3cd20943 06-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* Added new debug feature (DEBUG_PAGE_ACCESS) to detect invalid concurrent
access to a vm_page. It is basically an atomically accessed thread ID field
in the vm_page structure, which is explicitly set by macros marking the
critical sections. As a first positive effect I had to review quite a bit of
code and found several issues.
* Added several TODOs and comments. Some harmless ones, but also a few
troublesome ones in vm.cpp regarding page unmapping.
* file_cache: PrecacheIO::Prepare()/read_into_cache: Removed superfluous
vm_page_allocate_page() return value checks. It cannot fail anymore.
* Removed the heavily contended "pages" lock. We use different policies now:
- sModifiedTemporaryPages is accessed atomically.
- sPageDeficitLock and sFreePageCondition are protected by a new mutex.
- The page queues have individual locks (mutexes).
- Renamed set_page_state_nolock() to set_page_state(). Unless the caller says
otherwise, it does now lock the affected pages queues itself. Also changed
the return value to void -- we panic() anyway.
* set_page_state(): Add free/clear pages to the beginning of their respective
queues as this is more cache-friendly.
* Pages with the states PAGE_STATE_WIRED or PAGE_STATE_UNUSED are no longer
in any queue. They were in the "active" queue, but there's no good reason
to have them there. In case we decide to let the page daemon work the queues
(like FreeBSD) they would just be in the way.
* Pulled the common part of vm_page_allocate_page_run[_no_base]() into a helper
function. Also fixed a bug I introduced previously: The functions must not
vm_page_unreserve_pages() on success, since they remove the pages from the
free/clear queue without decrementing sUnreservedFreePages.
* vm_page_set_state(): Changed return type to void. The function cannot really
fail and no-one was checking it anyway.
* vm_page_free(), vm_page_set_state(): Added assertion: The page must not be
free/clear before. This is implied by the policy that no-one is allowed to
access free/clear pages without holding the respective queue's lock, which is
not the case at this point. This found the bug fixed in r34912.
* vm_page_requeue(): Added general assertions. panic() when requeuing of
free/clear pages is requested. Same reason as above.
* vm_clone_area(), B_FULL_LOCK case: Don't map busy pages. The implementation is
still not correct, though.

My usual -j8 Haiku build test runs another 10% faster, now. The total kernel
time drops about 18%. As hoped the new locks have only a fraction of the old
"pages" lock contention. Other locks lead the "most wanted list" now.



git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34933 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 66896bba 05-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

RemovePage() + InsertPage() == MovePage()


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34913 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 355dc6be 01-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

Inlined several VMCache methods.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34837 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 1021fd28 01-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* agp_gart(): Use vm_page_[un]reserve_pages().
* Removed unused vm_page_allocate_pages().
* Removed now unused (always true) "reserved" parameter from
vm_page_allocate_page().
* Removed unused (always false) "stealActive" parameter from steal_page().


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34836 a95241bf-73f2-0310-859d-f6bbb57e9c96


# eb8dc1eb 27-Dec-2009 Ingo Weinhold <ingo_weinhold@gmx.de>

* Removed DEBUG_PAGE_CACHE_TRANSITIONS debugging.
* Added VMCache::MovePage() and MoveAllPages() to move pages between caches.
* VMAnonymousCache:
- _MergeSwapPages(): Avoid doing anything, if neither cache has swapped out
pages.
- _MergeSwapPages() does now also remove source cache pages that are
shadowed by consumer swap pages. This allows us to call _MergeSwapPages()
before _MergePagesSmallerSource(), save the swap page shadowing check
there and get rid of the vm_page::merge_swap flag. This is an
optimization based on the assumption that usually none or only few pages
are swapped out, so we save a lot of checks.
- Implemented _MergePagesSmallerConsumer() as an alternative to
_MergePagesSmallerSource(). The former is used when the source cache has
more pages than the consumer cache. It iterates over the consumer cache's
pages, moves them to the source and finally moves all pages back to the
consumer. The final move is relatively cheap (though unfortunately we
still have to update all pages' vm_page::cache field), so that overall we
save iterations of the main loop with the more expensive checks.

The optimizations particularly improve the common fork()+exec*() situations.
fork() uses CoW, which is implemented by putting two new empty caches between
the to be copied area and its cache. exec*() destroys one copy of the area,
its cache and thus causes merging of the other new cache with the old cache.
Since this usually happens in a very short time, the old cache does still
contain many pages and the new cache only few. Previously the many pages were
all checked and moved individually. Now we do that for the few pages instead.

A very extreme example of this situation is the Haiku image build. jam has a
huge heap (> 200 MB) and it fork()s+exec*()s for every action to be executed.
Since during the cache merging the cache is locked, any write access to a
heap page causes jam to block until the cache merging is done. Formerly that
took so long that it killed a lot of parallelism in multi-job builds. That
could be observed particularly well when lots of small actions where executed
(like the Link, XRes, Mimeset, SetType, SetVersion combos when building
executables/libraries/add-ons). Those look dramatically better now.
The overall speed improvement for a -j8 image build on my machine is only
about 15%, though.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34784 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 2e74d74f 22-Dec-2009 Ingo Weinhold <ingo_weinhold@gmx.de>

* Added method VMCache::TransferAreas() moving areas from one cache to
another. The code originates from vm_copy_on_write_area(). We now generate
the VM cache tracing entries, though.
* count_writable_areas() -> VMCache::CountWritableAreas()
* Added debugger command "cache_stack" which is enabled when VM cache tracing
is enabled. It prints the source caches of a given cache or area at the
time of a specified tracing entry.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34751 a95241bf-73f2-0310-859d-f6bbb57e9c96


# a38f8503 22-Dec-2009 Ingo Weinhold <ingo_weinhold@gmx.de>

* arch_debug_get_stack_trace():
- Replaced the "userOnly" parameter by a "flags" parameter, that allows to
specify kernel and userland stack traces individually.
- x86, m68k: Don't always skip the first frame as that prevents the caller
from being able to record its own address.
* capture_tracing_stack_trace(): Replaced the "userOnly" parameter by
"kernelOnly", since one is probably always interested in the kernel stack
trace, but might not want the userland stack trace.
* Added stack trace support for VM cache kernel tracing.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34742 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 522c2f19 07-Dec-2009 Ingo Weinhold <ingo_weinhold@gmx.de>

* Added a simple mechanism to wait for events to VMCache. WaitForPageEvents()
waits for certain events on a given page, NotifyPageEvents() wakes up
waiting threads respectively.
* Used the new feature instead of condition variables for waiting on busy
pages. We save publishing and unpublishing of a condition variable whenever
a page is marked busy. There's only something to do, if there's at least
one thread waiting in the list of the respective cache. The general
assumption is that this is only rarely the case and even if it happens,
there should be only very few threads.
* Added an apparently missing notification in cache_io(). At least I didn't
see the reason for it not being there.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34537 a95241bf-73f2-0310-859d-f6bbb57e9c96


# f34a1dd5 02-Dec-2009 Ingo Weinhold <ingo_weinhold@gmx.de>

Created VMArea.{h,cpp} and moved VMArea and the global area hash table (new
class VMAreaHash) there.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34450 a95241bf-73f2-0310-859d-f6bbb57e9c96


# e50cf876 02-Dec-2009 Ingo Weinhold <ingo_weinhold@gmx.de>

* Moved the VM headers into subdirectory vm/.
* Renamed vm_cache.h/vm_address_space.h to VMCache.h/VMAddressSpace.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34449 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 271ac910a4cfdefa6393c1e7cb5e3a665404757d 09-Jan-2015 Adrien Destugues <pulkomandy@gmail.com>

Remove useless includes of khash.h

* These files were already converted to BOpenHashTable.
* For #9552.


# dac7b7c9805cb3c1291a98ceacb4dea94b0cfd65 06-Dec-2013 Ingo Weinhold <ingo_weinhold@gmx.de>

Fix various 64 bit related warnings

Mostly printf() format strings and signed-unsigned comparisons.
Fixes the x86_64 build.


# c8dd9f7780c426e592a3ccb231e6bfab51f15eb9 29-Oct-2013 Pawel Dziepak <pdziepak@quarnos.org>

kernel: Add thread_unblock() and use it where possible


# eca34ad1680056e2c7e757e4662199c80297cb4c 02-Dec-2012 Michael Lotz <mmlr@mlotz.ch>

Print page and cache using initial commands in panic message.


# 3d49fa31ec7d4c6e12adc3b4e520796aee1837a5 09-Nov-2012 Ithamar R. Adema <ithamar@upgrade-android.com>

VMCache: Fix broken trace statements


# 11d35d1b9b453cf95392b2ae8fa0941266e85d78 05-Jul-2012 Alex Smith <alex@alex-smith.me.uk>

Fixed tracing printf formats in VM code.


# 294711f98c107cf2d9d05b7fc34cd863e87bd358 27-Jun-2012 Alex Smith <alex@alex-smith.me.uk>

Changed {,u}int64 to be long rather than long long on x86_64.


# 4be4fc6b1faddbd037146214a0011d320842b4f3 15-Jun-2012 Alex Smith <alex@alex-smith.me.uk>

More 64-bit compilation/safety fixes.


# f8154d172da77bd77316f14c76d428bae7376323 02-Nov-2011 Ingo Weinhold <ingo_weinhold@gmx.de>

mmlr (distracted) + bonefish:
* Turn VMCache::consumers C list into a DoublyLinkedList.
* Use object caches for the different VMCache types and the VMCacheRefs.
The purpose is to reduce slab area fragmentation.
* Requires the introduction of a pure virtual VMCache::DeleteObject()
method, implemented in the derived classes.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@43133 a95241bf-73f2-0310-859d-f6bbb57e9c96


# ebf63109bb273a8f68476e0664debde48f36aea3 31-Oct-2011 Michael Lotz <mmlr@mlotz.ch>

Tiny style cleanup. No functional change.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@43044 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 24df65921befcd0ad0c5c7866118f922da61cb96 11-Jun-2011 Ingo Weinhold <ingo_weinhold@gmx.de>

Merged signals-merge branch into trunk with the following changes:
* Reorganized the kernel locking related to threads and teams.
* We now discriminate correctly between process and thread signals. Signal
handlers have been moved to teams. Fixes #5679.
* Implemented real-time signal support, including signal queuing, SA_SIGINFO
support, sigqueue(), sigwaitinfo(), sigtimedwait(), waitid(), and the addition
of the real-time signal range. Closes #1935 and #2695.
* Gave SIGBUS a separate signal number. Fixes #6704.
* Implemented <time.h> clock and timer support, and fixed/completed alarm() and
[set]itimer(). Closes #5682.
* Implemented support for thread cancellation. Closes #5686.
* Moved send_signal() from <signal.h> to <OS.h>. Fixes #7554.
* Lots over smaller more or less related changes.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@42116 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 4535495d80c86e19e2610e7444a4fcefe3e0f8e6 10-Jan-2011 Ingo Weinhold <ingo_weinhold@gmx.de>

Merged the signals branch into trunk, with these changes:
* The team and thread kernel structures have been renamed to Team and Thread
respectively and moved into the new BKernel namespace.
* Several (kernel add-on) sources have been converted from C to C++ since
private kernel headers are included that are no longer C compatible.

Changes after merging:
* Fixed gcc 2 build (warnings mainly in the scary firewire bus manager).


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@40196 a95241bf-73f2-0310-859d-f6bbb57e9c96


# a0d93d14160efe288a88cc2c8be594713ec731f2 02-Jan-2011 Ingo Weinhold <ingo_weinhold@gmx.de>

* VMCache::Unlock(): Renamed local variable consumerLocked to avoid shadowing
the parameter (CID 5329).
* _MergeWithOnlyConsumer(): Removed the somewhat weird consumerLocked
parameter. The caller can unlock itself, if desired. Improves Unlock()
readability.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@40084 a95241bf-73f2-0310-859d-f6bbb57e9c96


# b9447668707741085389f650383b018d33d7d0bf 10-Jul-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* Moved the vm_page initialization from vm_page.cpp:vm_page_init() to the new
vm_page::Init().
* Made vm_page::wired_count private and added accessor methods.
* Added VMCache::fWiredPagesCount (the number of wired pages the cache
contains) and accessor methods.
* Made more use of vm_page::IsMapped().
* vm_copy_on_write_area(): Added vm_page_reservation* parameter that can be
used to request a special handling for wired pages. If given the wired pages
are replaced by copies and the original pages are moved to the upper cache.
* vm_copy_area():
- We don't need to do any wired ranges handling, if the source area is a
B_SHARED_AREA, since we don't touch the area's mappings in this case.
- We no longer wait for wired ranges of the concerned areas to disappear.
Instead we use the new vm_copy_on_write_area() feature and just let it
copy the wired pages. This fixes #6288, an issue introduced with the use
of user mutexes in libroot: When executing multiple concurrent fork()s all
but the first one would wait on the fork mutex, which (being a user mutex)
would wire a page that the vm_copy_area() of the first fork() would wait
for.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37460 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 13638944dbc6efe0623b2623fb6eb5c8a69cb34c 21-Jun-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

Removed never read VMCache::scan_skip.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37195 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 377ecfe797a9f1009dd38702151d2a8c84723018 14-Jun-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* Renamed cache_type_to_string() to vm_cache_type_to_string() and made in
kernel private.
* Moved dumping code from dump_cache() to new VMCache::Dump().
* Override VMCache::Dump() in VMVnodeCache to also print the vnode.
* Removed no longer needed VMCache::GetLock().


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37138 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 1d578e15fe5b5c3ff62866ae81aef529d00d7762 02-Jun-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

Fixed more address types related issues. Mostly printf() or comparison
warnings, but also some oversights from earlier changes.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37000 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 435c43f5912b109e7d5cf682865d2061e62fad8c 02-Jun-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* Introduced type generic_io_vec, which is similar to iovec, but uses types
that are wide enough for both virtual and physical addresses.
* DMABuffer, IORequest, IOScheduler,... and code using them: Use
generic_io_vec and generic_{addr,size}_t where necessary.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@36997 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 6e83a6fac971dc2021617ade48a932900c54801a 20-Apr-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* VMCache::Resize(): Corrected TODO comment.
* Changed the semantics of VMCache::HasPage(). It was interpreted
inconsistently by the derived classes. Now it returns whether the backing
store can provide the page (via Read()). The default implementation returns
false. VNodeCache::HasPage() only returns true, if the given offset is
within the cache (i.e. file) bounds. This prevents vm_soft_fault() from
adding clean pages to vnode caches on faults beyond the file bounds.
Probably fixes #5473 -- at least mmap_resize_test behaves correctly, now.
* Removed redundant HasPage() and Fault() overrides in VMCache derived
classes.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@36374 a95241bf-73f2-0310-859d-f6bbb57e9c96


# efeca209a19f0c149b38f4ffc441be77921c1776 20-Apr-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

Made VMCache::Resize() virtual and let VMAnonymousCache override it to free
swap space when the cache shrinks. Currently the implementation stil leaks
swap space of busy pages.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@36373 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 5f310d4d0d6ff72ae8deb55a143c6dd343029110 13-Apr-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

Added TODO.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@36236 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 86875ad9d13d4ac67092fade0f423f261b19d417 13-Apr-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

Added VMCache::DebugHasPage() and DebugLookupPage() for use in the kernel
debugger.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@36228 a95241bf-73f2-0310-859d-f6bbb57e9c96


# bd7645a12ab594d5eb1c6d6a70c3a82a429410dd 20-Feb-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* Made vm_page::state private and added accessor methods.
* Added kernel tracing for page state transitions.



git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35538 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 40bb94819e6c39d72ab29edc1a0dcd80b15b8b42 03-Feb-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* Removed useless return parameter from vm_remove_all_page_mappings().
* Added vm_clear_page_mapping_accessed_flags() and
vm_remove_all_page_mappings_if_unaccessed(), which combine the functionality
of vm_test_map_activation(), vm_clear_map_flags(), and
vm_remove_all_page_mappings(), thus saving lots of calls to translation map
methods. The backend is the new method
VMTranslationMap::ClearAccessedAndModified().
* Started to make use of the cached page queue and changed the meaning of the
other non-free queues slightly:
- Active queue: Contains mapped pages that have been used recently.
- Inactive queue: Contains mapped pages that have not been used recently. Also
contains unmapped temporary pages.
- Modified queue: Contains unmapped modified pages.
- Cached queue: Contains unmapped unmodified pages (LRU sorted).
Unless we're actually low on memory and actively do paging, modified and
cached queues only contain non-temporary pages. Cached pages are considered
quasi free. They still belong to a cache, but since they are unmodified and
unmapped, they can be freed immediately. And this is what
vm_page_[try_]reserve_pages() do now when there are no more actually free
pages at hand. Essentially this means that pages storing cached file data,
unless mmap()ped, no longer are considered used and don't contribute to page
pressure. Paging will not happen as long there are enough free + cached pages
available.
* Reimplemented the page daemon. It no longer scans all pages, but instead works
the page queues. As long as the free pages situation is harmless, it only
iterates through the active queue and deactivates pages that have not been
used recently. When paging occurs it additionally scans the inactive queue and
frees pages that have not been used recently.
* Changed the page reservation/allocation interface:
vm_page_[try_]reserve_pages(), vm_page_unreserve_pages(), and
vm_page_allocate_page() now take a vm_page_reservation structure pointer.
The reservation functions initialize the structure -- currently consisting
only of a count member for the number of still reserved pages.
vm_page_allocate_page() decrements the count and vm_page_unreserve_pages()
unreserves the remaining pages (if any). Advantages are that reservation/
unreservation mismatches cannot occur anymore, that vm_page_allocate_page()
can verify that the caller has indeed a reserved page left, and that there's
no unnecessary pressure on the free page pool anymore. The only disadvantage
is that the vm_page_reservation object needs to be passed around a bit.
* Reworked the page reservation implementation:
- Got rid of sSystemReservedPages and sPageDeficit. Instead
sUnreservedFreePages now actually contains the number of free pages that
have not yet been reserved (it cannot become negative anymore) and the new
sUnsatisfiedPageReservations contains the number of pages that are still
needed for reservation.
- Threads waiting for reservations do now add themselves to a waiter queue,
which is ordered by descending priority (VM priority and thread priority).
High priority waiters are served first when pages become available.
Fixes #5328.
* cache_prefetch_vnode(): Would reserve one less page than allocated later, if
the size wasn't page aligned.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35393 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 72382fa6291e810be2949a70abd8f274f92dbd2c 29-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* Removed the page state PAGE_STATE_BUSY and instead introduced a vm_page::busy
flag. The obvious advantage is that one can still see what state a page is in
and even move it between states while being marked busy.
* Removed the vm_page::is_dummy flag. Instead we mark marker pages busy, which
in all cases has the same effect. Introduced a vm_page_is_dummy() that can
still check whether a given page is a dummy page.
* vm_page_unreserve_pages(): Before adding to the system reserve make sure
sUnreservedFreePages is non-negative. Otherwise we'd make nonexisting pages
available for allocation. steal_pages() still has the same problem and it
can't be solved that easily.
* map_page(): No longer changes the page state/mark the page unbusy. That's the
caller's responsibility.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35331 a95241bf-73f2-0310-859d-f6bbb57e9c96


# deee8524b7534d9b586cbcbf366d0660c9769a8e 26-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* Introduced {malloc,memalign,free}_etc() which take an additional "flags"
argument. They replace the previous special-purpose allocation functions
(malloc_nogrow(), vip_io_request_malloc()).
* Moved the I/O VIP heap to heap.cpp accordingly.
* Added quite a bit of passing around of allocation flags in the VM,
particularly in the VM*AddressSpace classes.
* Fixed IOBuffer::GetNextVirtualVec(): It was ignoring the VIP flag and always
allocated on the normal heap.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35316 a95241bf-73f2-0310-859d-f6bbb57e9c96


# cff6e9e406132a76bfc20cb35ff5228dd0ba94d8 26-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* The system now holds back a small reserve of committable memory and pages. The
memory and page reservation functions have a new "priority" parameter that
indicates how deep the function may tap into that reserve. The currently
existing priority levels are "user", "system", and "VIP". The idea is that
user programs should never be able to cause a state that gets the kernel into
trouble due to heavy battling for memory. The "VIP" level (not really used
yet) is intended for allocations that are required to free memory eventually
(in the page writer). More levels are thinkable in the future, like "user real
time" or "user system server".
* Added "priority" parameters to several VMCache methods.
* Replaced the map_backing_store() "unmapAddressRange" parameter by a "flags"
parameter.
* Added area creation flag CREATE_AREA_PRIORITY_VIP and slab allocator flag
CACHE_PRIORITY_VIP indicating the importance of the request.
* Changed most code to pass the right priorities/flags.

These changes already significantly improve the behavior in low memory
situations. I've tested a bit with 64 MB (virtual) RAM and, while not
particularly fast and responsive, the system remains at least usable under high
memory pressure.
As a side effect the slab allocator can now be used as general memory allocator.
Not done by default yet, though.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35295 a95241bf-73f2-0310-859d-f6bbb57e9c96


# ad6ad0f124076a9afce022ed4d5bb850089b78f8 24-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

VMCache::Init(): Initialize the debug_* members before allocating the
VMCacheRef object, since that can fail, in which case the subsequently called
Delete() would use uninitialized pointers.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35279 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 6379e53e2dd7021ba0e35d41c276dfe94c079596 19-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

vm_page no longer points directly to its containing cache, but rather to a
VMCacheRef object which points to the cache. This allows to optimize
VMCache::MoveAllPages(), since it no longer needs to iterate over all pages
to adjust their cache pointer. It can simple swap the cache refs of the two
caches instead.

Reduces the total -j8 Haiku image build time only marginally. The kernel time
drops almost 10%, though.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35155 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 3632eeedb954ead74b9cbdfcd664ff3dcb6eba57 18-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* VMCache: Added a UserData attribute which can be used by the lock holder.
* Added "bool consumerLocked" parameter to VMCache::Unlock() and
ReleaseRefAndUnlock(). Since Unlock() may cause the cache to be merged with
a consumer cache, the flag is needed to prevent a deadlock in case the
caller still holds a lock to the consumer. Hasn't been a problem yet, since
that situation never occurred.
* VMCacheChainLocker: Reversed unlocking order to bottom-up. The other
direction could cause a deadlock in case caches would be merged, since the
locking order would be reversed. The way VMCacheChainLocker was used this
didn't happen, though.
* fault_get_page(): While copying a page from a lower cache to the top cache,
we do now unlock all caches but the top one, so we don't unnecessarily
kill concurrency.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35153 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 31996a8e562c5c856e3afc4f0d2508395a4c8e9e 08-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

Added TODO.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34964 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 3cd2094396dde9ca42263c535041a95d5f0d5fff 06-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* Added new debug feature (DEBUG_PAGE_ACCESS) to detect invalid concurrent
access to a vm_page. It is basically an atomically accessed thread ID field
in the vm_page structure, which is explicitly set by macros marking the
critical sections. As a first positive effect I had to review quite a bit of
code and found several issues.
* Added several TODOs and comments. Some harmless ones, but also a few
troublesome ones in vm.cpp regarding page unmapping.
* file_cache: PrecacheIO::Prepare()/read_into_cache: Removed superfluous
vm_page_allocate_page() return value checks. It cannot fail anymore.
* Removed the heavily contended "pages" lock. We use different policies now:
- sModifiedTemporaryPages is accessed atomically.
- sPageDeficitLock and sFreePageCondition are protected by a new mutex.
- The page queues have individual locks (mutexes).
- Renamed set_page_state_nolock() to set_page_state(). Unless the caller says
otherwise, it does now lock the affected pages queues itself. Also changed
the return value to void -- we panic() anyway.
* set_page_state(): Add free/clear pages to the beginning of their respective
queues as this is more cache-friendly.
* Pages with the states PAGE_STATE_WIRED or PAGE_STATE_UNUSED are no longer
in any queue. They were in the "active" queue, but there's no good reason
to have them there. In case we decide to let the page daemon work the queues
(like FreeBSD) they would just be in the way.
* Pulled the common part of vm_page_allocate_page_run[_no_base]() into a helper
function. Also fixed a bug I introduced previously: The functions must not
vm_page_unreserve_pages() on success, since they remove the pages from the
free/clear queue without decrementing sUnreservedFreePages.
* vm_page_set_state(): Changed return type to void. The function cannot really
fail and no-one was checking it anyway.
* vm_page_free(), vm_page_set_state(): Added assertion: The page must not be
free/clear before. This is implied by the policy that no-one is allowed to
access free/clear pages without holding the respective queue's lock, which is
not the case at this point. This found the bug fixed in r34912.
* vm_page_requeue(): Added general assertions. panic() when requeuing of
free/clear pages is requested. Same reason as above.
* vm_clone_area(), B_FULL_LOCK case: Don't map busy pages. The implementation is
still not correct, though.

My usual -j8 Haiku build test runs another 10% faster, now. The total kernel
time drops about 18%. As hoped the new locks have only a fraction of the old
"pages" lock contention. Other locks lead the "most wanted list" now.



git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34933 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 66896bba13361874e677c96fc90690b9e75c2aeb 05-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

RemovePage() + InsertPage() == MovePage()


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34913 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 355dc6bef40b705a3299edee15ab39f64e6f9f5b 01-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

Inlined several VMCache methods.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34837 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 1021fd28262697dbbbe1d54a868f0672900c78f3 01-Jan-2010 Ingo Weinhold <ingo_weinhold@gmx.de>

* agp_gart(): Use vm_page_[un]reserve_pages().
* Removed unused vm_page_allocate_pages().
* Removed now unused (always true) "reserved" parameter from
vm_page_allocate_page().
* Removed unused (always false) "stealActive" parameter from steal_page().


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34836 a95241bf-73f2-0310-859d-f6bbb57e9c96


# eb8dc1ebfbe911a6af06efe02d003aa37687faad 27-Dec-2009 Ingo Weinhold <ingo_weinhold@gmx.de>

* Removed DEBUG_PAGE_CACHE_TRANSITIONS debugging.
* Added VMCache::MovePage() and MoveAllPages() to move pages between caches.
* VMAnonymousCache:
- _MergeSwapPages(): Avoid doing anything, if neither cache has swapped out
pages.
- _MergeSwapPages() does now also remove source cache pages that are
shadowed by consumer swap pages. This allows us to call _MergeSwapPages()
before _MergePagesSmallerSource(), save the swap page shadowing check
there and get rid of the vm_page::merge_swap flag. This is an
optimization based on the assumption that usually none or only few pages
are swapped out, so we save a lot of checks.
- Implemented _MergePagesSmallerConsumer() as an alternative to
_MergePagesSmallerSource(). The former is used when the source cache has
more pages than the consumer cache. It iterates over the consumer cache's
pages, moves them to the source and finally moves all pages back to the
consumer. The final move is relatively cheap (though unfortunately we
still have to update all pages' vm_page::cache field), so that overall we
save iterations of the main loop with the more expensive checks.

The optimizations particularly improve the common fork()+exec*() situations.
fork() uses CoW, which is implemented by putting two new empty caches between
the to be copied area and its cache. exec*() destroys one copy of the area,
its cache and thus causes merging of the other new cache with the old cache.
Since this usually happens in a very short time, the old cache does still
contain many pages and the new cache only few. Previously the many pages were
all checked and moved individually. Now we do that for the few pages instead.

A very extreme example of this situation is the Haiku image build. jam has a
huge heap (> 200 MB) and it fork()s+exec*()s for every action to be executed.
Since during the cache merging the cache is locked, any write access to a
heap page causes jam to block until the cache merging is done. Formerly that
took so long that it killed a lot of parallelism in multi-job builds. That
could be observed particularly well when lots of small actions where executed
(like the Link, XRes, Mimeset, SetType, SetVersion combos when building
executables/libraries/add-ons). Those look dramatically better now.
The overall speed improvement for a -j8 image build on my machine is only
about 15%, though.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34784 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 2e74d74f4f6d3023650b9525a425f760ea86f007 22-Dec-2009 Ingo Weinhold <ingo_weinhold@gmx.de>

* Added method VMCache::TransferAreas() moving areas from one cache to
another. The code originates from vm_copy_on_write_area(). We now generate
the VM cache tracing entries, though.
* count_writable_areas() -> VMCache::CountWritableAreas()
* Added debugger command "cache_stack" which is enabled when VM cache tracing
is enabled. It prints the source caches of a given cache or area at the
time of a specified tracing entry.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34751 a95241bf-73f2-0310-859d-f6bbb57e9c96


# a38f85036021b7ccaffa47fd8584afff473acf3d 22-Dec-2009 Ingo Weinhold <ingo_weinhold@gmx.de>

* arch_debug_get_stack_trace():
- Replaced the "userOnly" parameter by a "flags" parameter, that allows to
specify kernel and userland stack traces individually.
- x86, m68k: Don't always skip the first frame as that prevents the caller
from being able to record its own address.
* capture_tracing_stack_trace(): Replaced the "userOnly" parameter by
"kernelOnly", since one is probably always interested in the kernel stack
trace, but might not want the userland stack trace.
* Added stack trace support for VM cache kernel tracing.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34742 a95241bf-73f2-0310-859d-f6bbb57e9c96


# 522c2f19d458245474fcaf5b0254e0099906b117 07-Dec-2009 Ingo Weinhold <ingo_weinhold@gmx.de>

* Added a simple mechanism to wait for events to VMCache. WaitForPageEvents()
waits for certain events on a given page, NotifyPageEvents() wakes up
waiting threads respectively.
* Used the new feature instead of condition variables for waiting on busy
pages. We save publishing and unpublishing of a condition variable whenever
a page is marked busy. There's only something to do, if there's at least
one thread waiting in the list of the respective cache. The general
assumption is that this is only rarely the case and even if it happens,
there should be only very few threads.
* Added an apparently missing notification in cache_io(). At least I didn't
see the reason for it not being there.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34537 a95241bf-73f2-0310-859d-f6bbb57e9c96


# f34a1dd5d701373687b6f3f0e6e76bd2b1ae6007 02-Dec-2009 Ingo Weinhold <ingo_weinhold@gmx.de>

Created VMArea.{h,cpp} and moved VMArea and the global area hash table (new
class VMAreaHash) there.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34450 a95241bf-73f2-0310-859d-f6bbb57e9c96


# e50cf8765be50a7454c9488db38b638cf90805af 02-Dec-2009 Ingo Weinhold <ingo_weinhold@gmx.de>

* Moved the VM headers into subdirectory vm/.
* Renamed vm_cache.h/vm_address_space.h to VMCache.h/VMAddressSpace.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34449 a95241bf-73f2-0310-859d-f6bbb57e9c96