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.
