When copying an area with vm_copy_area only the new protection would be
applied and any possibly existing page protections on the source area
were ignored.
For areas with stricter area protection than page protection, this lead
to faults when accessing the copy. In the opposite case it lead to too
relaxed protection. The currently only user of vm_copy_area is
fork_team which goes through all areas of the parent and copies them to
the new team. Hence page protections were ignored on all forked teams.
Remove the protection argument and instead always carry over the source
area protection and duplicate the page protections when present.
Also make sure to take the page protections into account for deciding
whether or not the copy is writable and therefore needs to have copy on
write semantics.
Change-Id: I52f295f2aaa66e31b4900b754343b3be9a19ba30
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3166
Reviewed-by: waddlesplash <waddlesplash@gmail.com>
It was limited to a uint32 and could for example be overflown by the
slab MemoryManager that uses size_t on a 64 bit system.
This aligns the signature with create_area() that already uses size_t
for the size argument.
Note that the function is currently private, so the impact should be
limited.
* 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.
The cookie is used to store the base address of the area that was just
visited. On 64-bit systems, int32 is not sufficient. Therefore, changed
to ssize_t which retains compatibility on x86 while expanding to a
sufficient size on x86_64.
This adds a pair of functions vm_prepare_kernel_area_debug_protection()
and vm_set_kernel_area_debug_protection() to set a kernel area up for
page wise protection and to actually protect individual pages
respectively.
It was already possible to read and write protect full areas via area
protection flags and not mapping any actual pages. For areas that
actually have mapped pages this doesn't work however as no fault, at
which the permissions could be checked, is generated on access.
These new functions use the debug helpers of the translation map to mark
individual pages as non-present without unmapping them. This allows them
to be "protected", i.e. causing a fault on read and write access. As they
aren't actually unmapped they can later be marked present again.
Note that these are debug helpers and have quite a few restrictions as
described in the comment above the function and is only useful for some
very specific and constrained use cases.
* 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
vm_available_not_needed_memory() version that can be called from within the
kernel debugger.
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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
restrictions for virtual/physical addresses.
* vm_page_allocate_page_run():
- Fixed conversion of base/limit to array indexes. sPhysicalPageOffset was not
taken into account.
- Takes a physical_address_restrictions instead of base/limit and also
supports alignment and boundary restrictions, now.
* map_backing_store(), VM[User,Kernel]AddressSpace::InsertArea()/
ReserveAddressRange() take a virtual_address_restrictions parameter, now. They
also support an alignment independent from the range size.
* create_area_etc(), vm_create_anonymous_area(): Take
{virtual,physical}_address_restrictions parameters, now.
* Removed no longer needed B_PHYSICAL_BASE_ADDRESS.
* DMAResources:
- Fixed potential overflows of uint32 when initializing from device node
attributes.
- Fixed bounce buffer creation TODOs: By using create_area_etc() with the
new restrictions parameters we can directly support physical high address,
boundary, and alignment.
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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
where appropriate.
* Typedef'ed page_num_t to phys_addr_t and used it in more places in
vm_page.{h,cpp}.
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map_backing_store() doesn't commit memory when this flag is given.
* Used the new flag vm_copy_area(): We no longer commit memory for read-only
areas. This prevents read-only mapped files from suddenly requiring memory
after fork(). Might improve the situation on machines with very little RAM
a bit.
We should probably mark writable copies over-committing, since the usual
case is fork() + exec() where the child normally doesn't need more than a
few pages until calling exec(). That would significantly reduce the memory
requirement for jamming the Haiku tree.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@36651 a95241bf-73f2-0310-859d-f6bbb57e9c96
of consistency.
* Moved the B_OVERCOMMITTING_AREA flag from B_KERNEL_AREA_FLAGS to
B_USER_AREA_FLAGS, since we really allow it to be passed from userland.
* Most VM syscalls check the provided protection against B_USER_AREA_FLAGS
instead of B_USER_PROTECTION, now. This way they allow for
B_OVERCOMMITTING_AREA as well.
* _user_map_file(), _user_set_memory_protection(): Check the protection like
the other syscalls do and use fix_protection() instead of doing that
manually.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@36572 a95241bf-73f2-0310-859d-f6bbb57e9c96
mapped page.
* debug_{mem,strl}cpy():
- Added "team" parameter for specifying the address space the address are
to be interpreted in.
- When the standard memcpy() (with fault handler) fails, fall back to
vm_debug_copy_page_memory().
* Added debug_is_debugged_team(): Predicate returning true, if the supplied
team_id refers to the same team debug_get_debugged_thread() belongs to.
* Added DebuggedThreadSetter class for scope-based debug_set_debugged_thread().
Made use of it in several debugger functions.
* print_demangled_call() (x86): Fixed unsafe memory access.
Allows KDL stack traces to work correctly again, even if the page daemon has
already unmapped the concerned pages.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@36230 a95241bf-73f2-0310-859d-f6bbb57e9c96
* 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
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
* Added support to do larger raw allocations (up to one large chunk (128 pages))
in the slab areas. For an even larger allocation an area is created (haven't
seen that happen yet, though).
* Added kernel tracing (SLAB_MEMORY_MANAGER_TRACING).
* _FreeArea(): Copy and paste bug: The meta chunks of the to be freed area
would be added to the free lists instead of being removed from them. This
would corrupt the lists and also lead to all kinds of misuse of meta chunks.
object caches:
* Implemented CACHE_ALIGN_ON_SIZE. It is no longer set for all small object
caches, but the block allocator sets it on all power of two size caches.
* object_cache_reserve_internal(): Detect recursion and don't wait in such a
case. The function could deadlock itself, since
HashedObjectCache::CreateSlab() does allocate memory, thus potentially
reentering.
* object_cache_low_memory():
- I missed some returns when reworking that one in r35254, so the function
might stop early and also leave the cache in maintenance mode, which would
cause it to be ignored by object cache resizer and low memory handler from
that point on.
- Since ReturnSlab() potentially unlocks, the conditions weren't quite correct
and too many slabs could be freed.
- Simplified things a bit.
* object_cache_alloc(): Since object_cache_reserve_internal() does potentially
unlock the cache, the situation might have changed and their might not be an
empty slab available, but a partial one. The function would crash.
* Renamed the object cache tracing variable to SLAB_OBJECT_CACHE_TRACING.
* Renamed debugger command "cache_info" to "slab_cache" to avoid confusion with
the VMCache commands.
* ObjectCache::usage was not maintained anymore since I introduced the
MemoryManager. object_cache_get_usage() would thus always return 0 and the
block cache would not be considered cached memory. This was only of
informational relevance, though.
slab allocator misc.:
* Disable the object depots of block allocator caches for object sizes > 2 KB.
Allocations of those sizes aren't so common that the object depots yield any
benefit.
* The slab allocator is now fully self-sufficient. It allocates its bootstrap
memory from the MemoryManager, and the hash tables for HashedObjectCaches use
the block allocator instead of the heap, now.
* Added option to use the slab allocator for malloc() and friends
(USE_SLAB_ALLOCATOR_FOR_MALLOC). Currently disabled. Works in principle and
has virtually no lock contention. Handling for low memory situations is yet
missing, though.
* Improved the output of some debugger commands.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35283 a95241bf-73f2-0310-859d-f6bbb57e9c96
* Implemented a more elaborated raw memory allocation backend (MemoryManager).
We allocate 8 MB areas whose pages we allocate and map when needed. An area is
divided into equally-sized chunks which form the basic units of allocation. We
have areas with three possible chunk sizes (small, medium, large), which is
basically what the ObjectCache implementations were using anyway.
* Added "uint32 flags" parameter to several of the slab allocator's object
cache and object depot functions. E.g. object_depot_store() potentially wants
to allocate memory for a magazine. But also in pure freeing functions it
might eventually become useful to have those flags, since they could end up
deleting an area, which might not be allowable in all situations. We should
introduce specific flags to indicate that.
* Reworked the block allocator. Since the MemoryManager allocates block-aligned
areas, maintains a hash table for lookup, and maps chunks to object caches,
we can quickly find out which object cache a to be freed allocation belongs
to and thus don't need the boundary tags anymore.
* Reworked the slab boot strap process. We allocate from the initial area only
when really necessary, i.e. when the object cache for the respective
allocation size has not been created yet. A single page is thus sufficient.
other:
* vm_allocate_early(): Added boolean "blockAlign" parameter. If true, the
semantics is the same as for B_ANY_KERNEL_BLOCK_ADDRESS.
* Use an object cache for page mappings. This significantly reduces the
contention on the heap bin locks.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35232 a95241bf-73f2-0310-859d-f6bbb57e9c96
* Reorganized the code for [un]mapping pages:
- Added new VMTranslationMap::Unmap{Area,Page[s]}() which essentially do what
vm_unmap_page[s]() did before, just in the architecture specific code, which
allows for specific optimizations. UnmapArea() is for the special case that
the complete area is unmapped. Particularly in case the address space is
deleted, some work can be saved. Several TODOs could be slain.
- Since they are only used within vm.cpp vm_map_page() and vm_unmap_page[s]()
are now static and have lost their prefix (and the "preserveModified"
parameter).
* Added VMTranslationMap::Protect{Page,Area}(). They are just inline wrappers
for Protect().
* X86VMTranslationMap::Protect(): Make sure not to accidentally clear the
accessed/dirty flags.
* X86VMTranslationMap::Unmap()/Protect(): Make page table skipping actually
work. It was only skipping to the next page.
* Adjusted the PPC code to at least compile.
No measurable effect for the -j8 Haiku image build time, though the kernel time
drops minimally.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35089 a95241bf-73f2-0310-859d-f6bbb57e9c96
* ioapic_init(): map_physical_memory() was called for already mapped
addresses. This worked fine, but only because the x86 page mapping code
didn't mind.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35059 a95241bf-73f2-0310-859d-f6bbb57e9c96
