When we hit a COW fault and discover than no other process is sharing
the physical page, we simply remap it r/w and save ourselves the
trouble. When this happens, we can also give back (uncommit) one of our
shared committed COW pages, since we won't be needing it.
We had this optimization before, but I mistakenly removed it in
50472fd69f since I had misunderstood
it to be the reason for a panic.
We currently overcommit for COW when forking a process and cloning its
memory regions. Both the parent and child process share a set of.
committed COW pages.
If there's COW sharing across more than two processeses within a lineage
(e.g parent, child & grandchild), it's possible to exhaust these pages.
When the shared set is emptied, the next COW fault in each process must
detach from the shared set and fall back to on demand allocation.
This patch makes sure that we detach from the shared set once we
discover it to be empty (during COW fault handling). This fixes an issue
where we'd try to allocate from an exhausted shared set while building
GNU binutils inside SerenityOS.
It was doing a bunch of things it didn't need to do. I think we had
misunderstood the base class as having copied m_lock in its copy
constructor but it's actually default initialized.
We had issues with committed physical pages getting miscounted in some
situations, and instead of figuring out what was going wrong and making
sure all the commits had matching uncommits, this patch makes the
problem go away by adding an RAII class to manage this instead. :^)
MemoryManager::commit_user_physical_pages() now returns an (optional)
CommittedPhysicalPageSet. You can then allocate pages from the page set
by calling take_one() on it. Any unallocated pages are uncommitted upon
destruction of the page set.
This allows running QEMU inside WSL2 for hosts which have nested KVM
and WSLg support (e.g. Windows 11).
Running QEMU inside the WSL2 VM is slightly slower than running QEMU
on Windows, probably because of how WSLg handles screen updates.
Since we only ever add 1 super physical region, theres no reason to
add the extra redirection and allocation that comes with a dynamically
sized Vector.
We try to read twice from the RTC CMOS registers, and if the values are
not the same for 5 attempts, we know there's a malfunction with the
hardware so we declare these values as bogus in the kernel log.
When we try to query the time from the RTC CMOS, we try to check if
the CMOS is updated. If it is updated for a long period of time (as a
result of hardware malfunction), break the loop and return Unix epoch
time.
Previously, the loops would stop before reaching EOF, meaning that the
values that should have been set to EOF were left with their 0 initial
values. Now, we initialize to EOFs instead. The if/else inside the loops
always ran the else branch so I have removed the if branches.
With `IconPath`, you can override the icon used for the application
shortcut. This currently only supports resolving the icon through
`GUI::FileIconProvider`, the implementation for pointing to actual
image files is left as an exercise for the reader.
When installing an icon, we fall back to a resizing strategy when an
exact match on the image dimensions is missing. However, if we are
dealing with an `.ico` file with multiple indices, `convert` will
resize every separate index and will create multiple files.
This changes makes sure we only resize the first index. A future
improvement could be to select an index most closely matching the
requested dimensions.
There are a couple of minor nuances with parsing script values, compared
to other properties. In Scripts.txt, the UCD file lists the full name of
each script; other properties, like General Category, list the shorter
name in their primary files. This means that the aliases listed in
PropertyValueAliases.txt are reversed for script values.
Because setting the slider's value in the mousewheel handler will cause
the volume logarithm logic and the volume setting to happen anyways, we
don't need to do it in the mousewheel handler again. By just moving the
slider up and down with the scroll wheel, we mimic normal SliderWidget
behavior that doesn't exhibit the multiple previous bugs.
It takes a non-neglible amount of time to parse all of the UCD files and
generate the Unicode data files. To help compile times, only invoke the
generator once.
The current strategy of searching for a code point within the generated
table is slow for code points > U+0377 (the last code point whose index
is the same value as the code point itself). For larger code points, we
are doing a linear search through the table.
Instead, generate a HashMap of each code point to its entry in the table
for faster runtime lookups.
This had the added benefit of being able to remove a fair amount of code
from the generator. We no longer need to track that last contiguous code
point (U+0377) nor each code point's index in the generated table.
PrimitiveString may currently only be created with a UTF-8 string, and
it transcodes on the fly when a UTF-16 string is needed. Allow creating
a PrimitiveString from a UTF-16 string to avoid unnecessary transcoding
when the caller only wants UTF-16.
