Now modifying Scheduler.h or Thread.h doesnt trigger practically a full
kernel rebuild. This required moving Mutex and RWLock of of line but
that should be fine :^)
The old SpinLockAsMutex was pretty confusing first of all. It also was
causing the issue thats been around for maybe a year now which is the
only consistently happening kernel panic. I've been pretty confused
about this and finally figured out what was causing this.
The main issue was that we were accidentally enabling interrupts when
blocking a thread that passed SpinLockAsMutex from normally interrupt
enabled context. This led to receiving IPI for thread unblock while
we were actively blocking the thread. I'm very suprized this had't
caused any more serious issues than occasional kernel panics :^)
This was really hacky as it had no idea when the keyboard had events
and the blocking was just one millisecond sleeps :D
Now keyboard device checks if current tty is receiving input and if so
it forwards the events to the TTY.
- Removed virtual functions for all of the stat stuff.
This did however introduce some issues, mainly with /proc
becoming out of sync if you changed your ID. I propose we
do the linux thing and just have a stat update function
which is optional, but allows dynamic updates of stat fields
for cases such as those in uid/gid in /proc.
- Simplified the API, although still kind of annoying
it is a bit simpler.
- Moved some of the FS structure from having the FS inode inside
the in memory inode to a Serialise <-> Deserialise model where
Inodes are deserialised from disk into in memory ones and then
back into on disk ones when it comes time for syncing.
This makes it semantically better in my opinion, as it explicitly
separates disk and non-disk functionality.
This moves locking to the inodes themselves which allows reducing lock
times significantly. Main inodes (ext2 and tmpfs) still do contain a
single big mutex that gets locked during operations but now we have the
architecture to optimize these.
All block functions now take an optional mutex parameter that is
atomically unlocked instead of having the user unlock it before hand.
This prevents a ton of race conditions everywhere in the code!
This event is sent when user presses ctrl+{F1-F12} and it will dump the
corresponding processor's stack trace. This is really helpful for
detecting deadlocks in the system
This implementation is on top of inodes instead of fds as linux does it.
If I start finding ports/software that relies on epoll allowing
duplicate inodes, I will do what linux does.
I'm probably missing multiple epoll_notify's which may cause hangs but
the system seems to work fine :dd:
Change Semaphore -> ThreadBlocker
This was not a semaphore, I just named it one because I didn't know
what semaphore was. I have meant to change this sooner, but it was in
no way urgent :D
Implement SMP events. Processors can now be sent SMP events through
IPIs. SMP events can be sent either to a single processor or broadcasted
to every processor.
PageTable::{map_page,map_range,unmap_page,unmap_range}() now send SMP
event to invalidate TLB caches for the changed pages.
Scheduler no longer uses a global run queue. Each processor has its own
scheduler that keeps track of the load on the processor. Once every
second schedulers do load balancing. Schedulers have no access to other
processors' schedulers, they just see approximate loads. If scheduler
decides that it has too much load, it will send a thread to another
processor through a SMP event.
Schedulers are currently run using the timer interrupt on BSB. This
should be not the case, and each processor should use its LAPIC timer
for interrupts. There is no reason to broadcast SMP event to all
processors when BSB gets timer interrupt.
Old scheduler only achieved 20% idle load on qemu. That was probably a
very inefficient implementation. This new scheduler seems to average
around 1% idle load. This is much closer to what I would expect. On my
own laptop idle load seems to be only around 0.5% on each processor.
/dev/keyboard and /dev/mouse can be read for events from any attached
keyboard or mouse respectively. This makes device hot-plugging support
pretty much automatic for TTY, GUI, and whatever takes input.
PS/2 code is now kind of messed up, but it works. Keyboards and mice are
now an abstract class that is automatically exposed to userspace. This
will make adding USB input much nicer.
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