This avoids a race between getting the processor-specific SchedulerData
and accessing it. (Switching to a different CPU in that window means
that we're operating on the wrong SchedulerData.)
Co-authored-by: Tom <tomut@yahoo.com>
This always subtracted the glyph width of a space, despite isspace
also accepting newlines and a few other characters. It now also uses
AK/CharacterTypes.h. :^)
Non-printable characters should always have a width of 0. This is not
true for some characters like tab, but those can be exempted as the need
arises. Doing this here saves us from a bunch of checks in any place
that needs to figure out glyph widths for text which can contain
non-printable characters.
This more clearly expresses the purpose of this flag. Since only
CSS::WhiteSpace::Nowrap sets this value to false and it does not respect
linebreaks, this made the most sense as a flag name.
This commit refactors the text chunking algorithm used in
TextNode::ChunkIterator. The m_start_of_chunk member parameter has been
replaced with a local variable that's anchored to the current iterator
at the start of every next() call, and the algorithm is made a little
more clear by explicitly separating what can and cannot peek into the
next character during iteration.
Prior to this change, both uid_t and gid_t were typedef'ed to `u32`.
This made it easy to use them interchangeably. Let's not allow that.
This patch adds UserID and GroupID using the AK::DistinctNumeric
mechanism we've already been employing for pid_t/ProcessID.
We don't need transitions for either of these:
- Adding the 'name' property to a constructor object
- Adding the 'constructor' property to its prototype object
- Replace the misleading abuse of the m_transitions_enabled flag for the
fast path without lookup with a new m_initialized boolean that's set
either by Heap::allocate() after calling the Object's initialize(), or
by the GlobalObject in its special initialize_global_object(). This
makes it work regardless of the shape's uniqueness.
- When we're adding a new property past the initialization phase,
there's no need to do a second metadata lookup to retrieve the storage
value offset - it's known to always be the shape's property count
minus one. Also, instead of doing manual storage resizing and
assignment via indexing, just use Vector::append().
- When we didn't add a new property but are overwriting an existing one,
the property count and therefore storage value offset doesn't change,
so we don't have to retrieve it either.
As a result, Object::set_shape() is now solely responsible for updating
the m_shape pointer and is not resizing storage anymore, so I moved it
into the header.
We don't need to be allocating Strings for these names during static
initialization. The C-string literals will be stored in the .rodata ELF
section, so they're not going anywhere. We can just wrap the .rodata
storage for the class names in StringViews and use those in Object
registration and lookup APIs.
Add a dummy Arch/aarch64/boot.S that for now does nothing but
let all processor cores sleep.
For now, none of the actual Prekernel code is built for aarch64.
This should help prevent deadlocks where a thread blocks on a Mutex
while interrupts are disabled, and makes it impossible for the holder of
the Mutex to make forward progress because it cannot be scheduled in.
Hide it behind a new debug macro LOCK_IN_CRITICAL_DEBUG for now, because
Ext2FS takes a series of Mutexes from the page fault handler, which
executes with interrupts disabled.
Previously, we would try to acquire a reference to the all processes
lock or other contended resources while holding both the scheduler lock
and the thread's blocker lock. This could lead to a deadlock if we
actually have to block on those other resources.
There are callers of processes().with or processes().for_each that
require interrupts to be disabled. Taking a Mutexe with interrupts
disabled is a recipe for deadlock, so convert this to a Spinlock.
There's no need to disable interrupts when trying to access an inode's
shared vmobject. Additionally, Inode::shared_vmobject() acquires a Mutex
which is a recipe for deadlock if acquired with interrupts disabled.
Optimizations:
- Make sure `DT_SYMTAB` is a string view literal, instead of string.
- DynamicObject::HashSection::lookup_sysv_symbol should be using
raw_name() from symbol comparison to avoid needlessly calling
`strlen`, when the StrinView::operator= walks the cstring without
calling `strlen` first.
- DynamicObject::HashSection::lookup_gnu_symbol shouldn't create a
symbol unless we know the hashes match first.
In order to test these changes I enabled Undefined behavior sanitizer
which creates a huge amount of relocations, and then ran the browser
with the help argument 100 times. The browser is a fairly big app with
a few different libraries being loaded, so it seemed liked a good
target.
Command: `time -n 100 br --help`
Before:
```
Timing report:
==============
Command: br --help
Average time: 3897.679931 ms
Excluding first: 3901.242431 ms
```
After:
```
Timing report:
==============
Command: br --help
Average time: 3612.860107 ms
Excluding first: 3613.54541 ms
```
The kernel profiles were recently changed to have a `strings` array
as part of the profile objects. The `ProfileViewer` now checks for
that during startup and declares the profile invalid if the array
is not present.
The UserspaceEmulator doesn't use the API which the kernel exposed
the string array for, so just fake it by always adding an empty array
to the generated profiles.
The fact that profiles are json on one giant line makes them very
difficult to debug when things go wrong. Instead make sure to wrap
each event or sample on a newline so you can easily grep/heap/tail
the profile files.
