kernel/vm: Completely replace mlock() implementation.

The old implementation used the real lock_memory(). This is problematic
and does not work for a large number of reasons:

1) Various parts of the kernel assume memory is locked only very
temporarily, and will often wait on locked memory to become unlocked.
The transient nature of locks is further demonstrated by the fact that
lock_memory acquires references to structures, like the address space,
which are only released by unlock_memory

2) The VM has a hard assumption that all lock_memory calls will be
exactly balanced, and maintains internal "WiredRange" structures
on areas, etc. corresponding to the original lock_memory calls.
Maintaining separate data structures as this code did is a recipe
for even more problems when the structures are manipulated separately,
leading to confusing or incorrect behavior on unlocks.

3) Areas with locked memory cannot be deleted, nor can the pages which are
locked be removed from the areas/caches. This of course is most notable
when destroying teams which locked memory, but the problem also occurs
when just using delete_area, resize_area, mmap/munmap, etc.

Because of (2) and especially (3), adding support for mlock()-like semantics
to the existing memory locking system is just not a good option. A further
reason is that our lock_memory is much stricter than mlock(), which only
demands the pages in question must remain resident in RAM and cannot be
swapped out (or, it seems, otherwise written back to disk.)

Thus, this commit completely removes the old implementation (which
was seriously broken and did not actually automatically unlock memory
on team exit or area destruction at all, etc.) and instead adds a new
feature to VMAnonymousCache to block certain pages from being written out.
The syscall then just invokes this to do its work.

Fixes #17674. Related to #13651.

Change-Id: Id2745c51796bcf9a74ba5325fe686a95623cd521
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5147
Reviewed-by: waddlesplash <waddlesplash@gmail.com>

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>

kernel/vm: Whitespace cleanup only.

VMAnonymousCache: Reuse _FreeSwapPageRange in destructor.

The use of individual _SwapBlockGetAddress() and _SwapBlockFree() calls
would lock and unlock the swap hash for each page.

Using _FreeSwapPageRange() also allows to skip entire blocks when they
are not present or get empty early.

Change-Id: Ia76735e514cf8967d282e099cf5409fe1b104297
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2590
Reviewed-by: waddlesplash <waddlesplash@gmail.com>

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>

VMAnonymousCache: Factor out page freeing from Resize/Rebase.

Except for the offsets the code was identical. Also simplify the
conditions with early returns.

Change-Id: Ia7c44578ab06e571f6bf992db6c6d3493fd93230
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2582
Reviewed-by: waddlesplash <waddlesplash@gmail.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>

kernel, libroot: Add more memory info in system_info

system_info now contains all information previously available only
through __get_system_info_etc(B_MEMORY_INFO, ...).

Revert "VMAnonymousCache.cpp: changed page_index type to page_num_t"

This reverts commit f7176b0ee50d5367762d904a943a693b0a8e3e2f. Citing Ingo:
"off_t is the correct type to use for addressing pages in a cache/file,
which page_num_t should only be used for physical pages." I'll see how to
fix the GCC 4.7 warnings differently :)

VMAnonymousCache.cpp: changed page_index type to page_num_t

* consistently use page_num_t for page numbers and off_t for offsets and sizes.

Add support for pthread_attr_get/setguardsize()

* Added the aforementioned functions.
* create_area_etc() now takes a guard size parameter.
* The thread_info::stack_base/end range now refers to the usable range
only.

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

Revert change that did accidentally sneak into the style cleanup.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@43124 a95241bf-73f2-0310-859d-f6bbb57e9c96

Style cleanup. No functional change.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@43122 a95241bf-73f2-0310-859d-f6bbb57e9c96

Replaced the swap_addr_t and SWAP_SLOT_NONE in RadixBitmap.{h,cpp} by
radix_slot_t and RADIX_SLOT_NONE.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@36998 a95241bf-73f2-0310-859d-f6bbb57e9c96

* 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

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

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

* 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

* 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

Moved merging swap pages from Merge() to a separate method.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34779 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Some style cleanup.
* Pulled the code moving the pages out of Merge() into a separate method.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34778 a95241bf-73f2-0310-859d-f6bbb57e9c96

Moved VMCache related definitions to <vm/VMCache.h>.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34535 a95241bf-73f2-0310-859d-f6bbb57e9c96

* 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

Renamed vm_address_space to VMAddressSpace.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34422 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Rework page writing to combine page writes where possible. For now the pages
are required to be physically contiguos, which should be reworked to put them
into seperate iovecs. Still this manages to combine a great deal of page
writes into larger bursts already. Reduces the amount of IO requests being
scheduled (and greatly benefits media where page wise writes are slow when
they are accessed through a non-IOScheduler path, i.e. USB mass storage until
that is properly implemented).
* Abstracted per page page writing tasks into a PageWriteWrapper class.
* Abstracted per transfer page writing tasks into PageWriteTransfer class which
formerly was the PageWriterCallback.
* Use both classes from the PageWriterRun and from
vm_page_write_modified_page_range to remove code duplication.
* Adjusted synchronous VMAnonymousCache::Write() to cope correctly with larger
iovecs and more than one iovec. It assumed that there was exactly one page per
vector previously.
* Introduced MaxPagesPerWrite() and MaxPagesPerAsyncWrite() to VMCache to allow
a cache to specify restricitions. VMAnonymousCache does restrict the max pages
to 1 for WriteAsync right now as I didn't feel like reworking that one to cope
with non single page writes just yet.
* Pulled out PageWriteTransfer methods for better readability.
* Some typo fixes.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@33507 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Introduces VMCache::CanWritePage() returning whether the given cache can
theoretically write the given page.
* page writer: Fixed the incorrect check whether a temporary page can be
written by using the new CanWritePage().


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@30281 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Added "flags" parameter to VMCache::Read().
* Use the new VMCache::Read() flags parameter to directly read into the
physical page in the page fault handler instead of mapping it first.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27966 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Fixed the build when ENABLE_SWAP_SUPPORT is not defined.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27838 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Implemented a (private for now) get_system_info_etc() call, that can retrieve
various system information.
* Implemented retrieving some VM stats via this call.
* The VM now maintains a page fault counter, and sets system_info::page_faults
accordingly.
* Added a (pretty simple) "vmstat" command line app.
* Minor cleanup.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27597 a95241bf-73f2-0310-859d-f6bbb57e9c96

* vm_page: Swapped members usage_count and wired_count. We lost 4 bytes
due to alignment padding before.
* Reorganized merging of caches a bit. Renamed MergeStore() to Merge()
and moved some more functionality into it. The method also moves the
pages from source to consumer, now. This is necessary, since
VMAnonymousCache needs to consider both physical pages and swap pages
at the same time. Before we first moved the physical pages and the
swap pages later, which was broken for two reasons: (1) A swap page in
the consumer cache shadows a physical page of the source cache, which
we ignored. (2) A source cache's physical page that also had a swap
page would lose the latter in the process when moved to the consumer
cache, i.e. if the page was not marked modified, it could be stolen
and its data would be lost.

These changes improve the situation when building Haiku with 256 MB RAM
in that jam doesn't crash anymore, but in my test the system became
totally unusable after about an hour or 7000 targets (GUI froze). For
some reason it didn't manage to free pages anymore although swapping
heavily.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27179 a95241bf-73f2-0310-859d-f6bbb57e9c96

Implemented (a simple) WriteAsync(), i.e. swap pages are now written
asynchronously, too.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27077 a95241bf-73f2-0310-859d-f6bbb57e9c96

Patch by Zhao Shuai with small changes by myself:
* Some renaming: A location in a swap file where a page can be stored is
now called "slot" instead of "page" or "swap page".
* swap_slot_alloc(): Update the hint more correctly after allocating
slots at the hint.
* swap_space_reserve(): When less than the requested space could be
reserved, it always returned 0 and leaked the remaining pages.
* swap_file_delete(): sSwapFileListLock wasn't unlocked in error cases.
Use MutexLocker now.
* swap_free_page_swap_space(): sAvailSwapSpace wasn't updated.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27057 a95241bf-73f2-0310-859d-f6bbb57e9c96

* VMCache::Write(): Added "uint32 flags" argument which is supposed to
be passed on to the IORequest. Most relevantly physical pages can now
be written directly by passing B_PHYSICAL_IO_REQUEST.
* Added VMCache::WriteAsync() which is supposed to write pages
asynchronously. The base class version version falls back to the
synchronous Write(). Only VMVnodeCache implements WriteAsync() ATM,
VMAnonymousCache (swap support) still has to be adjusted accordingly.
* write_page() doesn't need to map the page anymore as it can write the
physical page directly.
* Modified the page writer to write pages asynchronously. This shouldn't
have any noticeable effect yet. It will though as soon as the I/O
scheduler reorders I/O operations.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27056 a95241bf-73f2-0310-859d-f6bbb57e9c96

Patch by Zhao Shuai with minor changes by myself:
* Moved the static functions to the beginning of the file.
* Renamed several variables for more clarity, particularly
offset/cacheOffset to index/pageIndex in case where the unit is pages.
* _SwapBlock{Build,Free}() can deal with a range of pages now, which
should be more efficient.
* Additional checks/panics in swap_page_alloc().
* swap_file_add(): Wrong byte count was used when allocating and
clearing the bitmap.
* swap_page_alloc(): Fixed off-by-one check. The last page of the swap
file could not be used.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26975 a95241bf-73f2-0310-859d-f6bbb57e9c96

Patch by Zhao Shuai with some changes by myself:
* Added functions swap_free_page_swap_space(), swap_available_pages(),
and swap_total_swap_pages(). They will be used by the page daemon
code.
* Free allocated swap space in the VMAnonymousCache destructor.
* Write(): First free swap space assigned to the pages to be written
(was leaked before) and update fAllocatedSwapSize upfront. Both is now
done with the cache locked, as it should be.
* Fixes several instance where the cache offset in bytes was used
instead of in pages.
* Print the correct error when _kern_write_stat() fails.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26926 a95241bf-73f2-0310-859d-f6bbb57e9c96

Patch by Zhao Shuai with changes by myself:
* Keep track of the stack space actually allocated for the cache and let
Write() fail when we've already allocated as much as reserved.
* Added second phase of swap initialization (swap_init_post_modules())
which reads the virtual memory driver settings and creates/resizes a
swap file. ATM truncate() is used to resize the swap file, but that is
a bit slow. We should probably introduce a VFS function to use BFS's
fast method.

This should make swap support work somewhat, but since swap space is
never freed ATM this would be a relatively short pleasure. Still
disabled by default.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26783 a95241bf-73f2-0310-859d-f6bbb57e9c96

Moved ENABLE_SWAP_SUPPORT definition to vm_types.h


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26640 a95241bf-73f2-0310-859d-f6bbb57e9c96

Patch by Zhao Shuai with changes by myself:
* Init swap support in main().
* Added "bool swappable" parameter to
VMCacheFactory::CreateAnonymousCache(). A cache supporting swapping
is created when true. Adjusted invocations accordingly.
* The page writer does now write non-locked swappable pages (when
memory is low).
* Fixed header guard of VMAnonymousNoSwapCache.h.
* Swap support is compiled conditionally, controlled by the
ENABLE_SWAP_SUPPORT in src/system/kernel/vm/VMAnonymousCache.h. It is
disabled ATM. Since no swap files are added, it wouldn't have much
effect anyway.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26625 a95241bf-73f2-0310-859d-f6bbb57e9c96

* bfs_fsync() was the only place which could cause the
fs_vnode_ops::write_pages() to be called with fsReenter = true. Since
this is no longer the case, the argument has become superfluous. For
read_pages() it always was. Removed the argument from the functions
and all functions that propagated it.
* Some whitespace at the end of lines was removed.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26579 a95241bf-73f2-0310-859d-f6bbb57e9c96

Merged branch haiku/branches/developer/bonefish/vm into trunk. This
introduces the following relevant changes:
* VMCache:
- Renamed vm_cache to VMCache, merged it with vm_store and made it a
C++ class with virtual methods (replacing the store operations).
Turned the different store implementations into subclasses.
- Introduced MergeStore() callback, changed semantics of Commit().
- Changed locking and referencing semantics. A reference can only be
acquired/released with the cache locked. An unreferenced cache is
deleted and a mergeable cache merged when it is unlocked. This
removes the "busy" state of a cache and simplifies the page fault
code.
* Added VMAnonymousCache, which will implement swap support (work by
Zhao Shuai). It is not integrated and used yet, though.
* Enabled the mutex/recursive lock holder asserts.
* Fixed DoublyLinkedList::Swap().
* Generalized the low memory handler to a low resource handler. And made
semaphores and reserved memory handled resources. Made
vm_try_resource_memory() optionally wait (with timeout), and used that
feature to reserve memory for areas.
...


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26572 a95241bf-73f2-0310-859d-f6bbb57e9c96

kernel, libroot: Add more memory info in system_info

system_info now contains all information previously available only
through __get_system_info_etc(B_MEMORY_INFO, ...).

Revert "VMAnonymousCache.cpp: changed page_index type to page_num_t"

This reverts commit f7176b0ee50d5367762d904a943a693b0a8e3e2f. Citing Ingo:
"off_t is the correct type to use for addressing pages in a cache/file,
which page_num_t should only be used for physical pages." I'll see how to
fix the GCC 4.7 warnings differently :)

VMAnonymousCache.cpp: changed page_index type to page_num_t

* consistently use page_num_t for page numbers and off_t for offsets and sizes.

Add support for pthread_attr_get/setguardsize()

* Added the aforementioned functions.
* create_area_etc() now takes a guard size parameter.
* The thread_info::stack_base/end range now refers to the usable range
only.

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

Revert change that did accidentally sneak into the style cleanup.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@43124 a95241bf-73f2-0310-859d-f6bbb57e9c96

Style cleanup. No functional change.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@43122 a95241bf-73f2-0310-859d-f6bbb57e9c96

Replaced the swap_addr_t and SWAP_SLOT_NONE in RadixBitmap.{h,cpp} by
radix_slot_t and RADIX_SLOT_NONE.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@36998 a95241bf-73f2-0310-859d-f6bbb57e9c96

* 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

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

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

* 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

* 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

Moved merging swap pages from Merge() to a separate method.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34779 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Some style cleanup.
* Pulled the code moving the pages out of Merge() into a separate method.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34778 a95241bf-73f2-0310-859d-f6bbb57e9c96

Moved VMCache related definitions to <vm/VMCache.h>.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34535 a95241bf-73f2-0310-859d-f6bbb57e9c96

* 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

Renamed vm_address_space to VMAddressSpace.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34422 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Rework page writing to combine page writes where possible. For now the pages
are required to be physically contiguos, which should be reworked to put them
into seperate iovecs. Still this manages to combine a great deal of page
writes into larger bursts already. Reduces the amount of IO requests being
scheduled (and greatly benefits media where page wise writes are slow when
they are accessed through a non-IOScheduler path, i.e. USB mass storage until
that is properly implemented).
* Abstracted per page page writing tasks into a PageWriteWrapper class.
* Abstracted per transfer page writing tasks into PageWriteTransfer class which
formerly was the PageWriterCallback.
* Use both classes from the PageWriterRun and from
vm_page_write_modified_page_range to remove code duplication.
* Adjusted synchronous VMAnonymousCache::Write() to cope correctly with larger
iovecs and more than one iovec. It assumed that there was exactly one page per
vector previously.
* Introduced MaxPagesPerWrite() and MaxPagesPerAsyncWrite() to VMCache to allow
a cache to specify restricitions. VMAnonymousCache does restrict the max pages
to 1 for WriteAsync right now as I didn't feel like reworking that one to cope
with non single page writes just yet.
* Pulled out PageWriteTransfer methods for better readability.
* Some typo fixes.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@33507 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Introduces VMCache::CanWritePage() returning whether the given cache can
theoretically write the given page.
* page writer: Fixed the incorrect check whether a temporary page can be
written by using the new CanWritePage().


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@30281 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Added "flags" parameter to VMCache::Read().
* Use the new VMCache::Read() flags parameter to directly read into the
physical page in the page fault handler instead of mapping it first.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27966 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Fixed the build when ENABLE_SWAP_SUPPORT is not defined.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27838 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Implemented a (private for now) get_system_info_etc() call, that can retrieve
various system information.
* Implemented retrieving some VM stats via this call.
* The VM now maintains a page fault counter, and sets system_info::page_faults
accordingly.
* Added a (pretty simple) "vmstat" command line app.
* Minor cleanup.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27597 a95241bf-73f2-0310-859d-f6bbb57e9c96

* vm_page: Swapped members usage_count and wired_count. We lost 4 bytes
due to alignment padding before.
* Reorganized merging of caches a bit. Renamed MergeStore() to Merge()
and moved some more functionality into it. The method also moves the
pages from source to consumer, now. This is necessary, since
VMAnonymousCache needs to consider both physical pages and swap pages
at the same time. Before we first moved the physical pages and the
swap pages later, which was broken for two reasons: (1) A swap page in
the consumer cache shadows a physical page of the source cache, which
we ignored. (2) A source cache's physical page that also had a swap
page would lose the latter in the process when moved to the consumer
cache, i.e. if the page was not marked modified, it could be stolen
and its data would be lost.

These changes improve the situation when building Haiku with 256 MB RAM
in that jam doesn't crash anymore, but in my test the system became
totally unusable after about an hour or 7000 targets (GUI froze). For
some reason it didn't manage to free pages anymore although swapping
heavily.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27179 a95241bf-73f2-0310-859d-f6bbb57e9c96

Implemented (a simple) WriteAsync(), i.e. swap pages are now written
asynchronously, too.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27077 a95241bf-73f2-0310-859d-f6bbb57e9c96

Patch by Zhao Shuai with small changes by myself:
* Some renaming: A location in a swap file where a page can be stored is
now called "slot" instead of "page" or "swap page".
* swap_slot_alloc(): Update the hint more correctly after allocating
slots at the hint.
* swap_space_reserve(): When less than the requested space could be
reserved, it always returned 0 and leaked the remaining pages.
* swap_file_delete(): sSwapFileListLock wasn't unlocked in error cases.
Use MutexLocker now.
* swap_free_page_swap_space(): sAvailSwapSpace wasn't updated.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27057 a95241bf-73f2-0310-859d-f6bbb57e9c96

* VMCache::Write(): Added "uint32 flags" argument which is supposed to
be passed on to the IORequest. Most relevantly physical pages can now
be written directly by passing B_PHYSICAL_IO_REQUEST.
* Added VMCache::WriteAsync() which is supposed to write pages
asynchronously. The base class version version falls back to the
synchronous Write(). Only VMVnodeCache implements WriteAsync() ATM,
VMAnonymousCache (swap support) still has to be adjusted accordingly.
* write_page() doesn't need to map the page anymore as it can write the
physical page directly.
* Modified the page writer to write pages asynchronously. This shouldn't
have any noticeable effect yet. It will though as soon as the I/O
scheduler reorders I/O operations.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27056 a95241bf-73f2-0310-859d-f6bbb57e9c96

Patch by Zhao Shuai with minor changes by myself:
* Moved the static functions to the beginning of the file.
* Renamed several variables for more clarity, particularly
offset/cacheOffset to index/pageIndex in case where the unit is pages.
* _SwapBlock{Build,Free}() can deal with a range of pages now, which
should be more efficient.
* Additional checks/panics in swap_page_alloc().
* swap_file_add(): Wrong byte count was used when allocating and
clearing the bitmap.
* swap_page_alloc(): Fixed off-by-one check. The last page of the swap
file could not be used.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26975 a95241bf-73f2-0310-859d-f6bbb57e9c96

Patch by Zhao Shuai with some changes by myself:
* Added functions swap_free_page_swap_space(), swap_available_pages(),
and swap_total_swap_pages(). They will be used by the page daemon
code.
* Free allocated swap space in the VMAnonymousCache destructor.
* Write(): First free swap space assigned to the pages to be written
(was leaked before) and update fAllocatedSwapSize upfront. Both is now
done with the cache locked, as it should be.
* Fixes several instance where the cache offset in bytes was used
instead of in pages.
* Print the correct error when _kern_write_stat() fails.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26926 a95241bf-73f2-0310-859d-f6bbb57e9c96

Patch by Zhao Shuai with changes by myself:
* Keep track of the stack space actually allocated for the cache and let
Write() fail when we've already allocated as much as reserved.
* Added second phase of swap initialization (swap_init_post_modules())
which reads the virtual memory driver settings and creates/resizes a
swap file. ATM truncate() is used to resize the swap file, but that is
a bit slow. We should probably introduce a VFS function to use BFS's
fast method.

This should make swap support work somewhat, but since swap space is
never freed ATM this would be a relatively short pleasure. Still
disabled by default.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26783 a95241bf-73f2-0310-859d-f6bbb57e9c96

Moved ENABLE_SWAP_SUPPORT definition to vm_types.h


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26640 a95241bf-73f2-0310-859d-f6bbb57e9c96

Patch by Zhao Shuai with changes by myself:
* Init swap support in main().
* Added "bool swappable" parameter to
VMCacheFactory::CreateAnonymousCache(). A cache supporting swapping
is created when true. Adjusted invocations accordingly.
* The page writer does now write non-locked swappable pages (when
memory is low).
* Fixed header guard of VMAnonymousNoSwapCache.h.
* Swap support is compiled conditionally, controlled by the
ENABLE_SWAP_SUPPORT in src/system/kernel/vm/VMAnonymousCache.h. It is
disabled ATM. Since no swap files are added, it wouldn't have much
effect anyway.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26625 a95241bf-73f2-0310-859d-f6bbb57e9c96

* bfs_fsync() was the only place which could cause the
fs_vnode_ops::write_pages() to be called with fsReenter = true. Since
this is no longer the case, the argument has become superfluous. For
read_pages() it always was. Removed the argument from the functions
and all functions that propagated it.
* Some whitespace at the end of lines was removed.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26579 a95241bf-73f2-0310-859d-f6bbb57e9c96

Merged branch haiku/branches/developer/bonefish/vm into trunk. This
introduces the following relevant changes:
* VMCache:
- Renamed vm_cache to VMCache, merged it with vm_store and made it a
C++ class with virtual methods (replacing the store operations).
Turned the different store implementations into subclasses.
- Introduced MergeStore() callback, changed semantics of Commit().
- Changed locking and referencing semantics. A reference can only be
acquired/released with the cache locked. An unreferenced cache is
deleted and a mergeable cache merged when it is unlocked. This
removes the "busy" state of a cache and simplifies the page fault
code.
* Added VMAnonymousCache, which will implement swap support (work by
Zhao Shuai). It is not integrated and used yet, though.
* Enabled the mutex/recursive lock holder asserts.
* Fixed DoublyLinkedList::Swap().
* Generalized the low memory handler to a low resource handler. And made
semaphores and reserved memory handled resources. Made
vm_try_resource_memory() optionally wait (with timeout), and used that
feature to reserve memory for areas.
...


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26572 a95241bf-73f2-0310-859d-f6bbb57e9c96