Refactor kernel memory usage #183
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| process_table Pointer to process table in the heap | ||
| active_processes Number of active processes | ||
| current_process Index of the currently running process | ||
| last_pid The last PID allocated by the kernel |
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These variables are currently called threadTable, activeThreads, currentThreadIndex, and lastThreadID. Part of this change is to rename all of the kernel internal memory to use snake_case. Also, note that threadTable is a fixed address currently - you'll have to stick two bytes of memory somewhere in the kernel state and update code that refers to threadTable to read that instead.
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| 0x0006 0x02 Pointer to file handle table | ||
| 0x0008 0x02 Pointer to library handle table | ||
| 0x000A 0x02 Pointer to signal table | ||
| 0x000C 0x03 Reserved for future use |
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Note that the length of a process entry has changed.
| 1: EoF if 1 | ||
| 2: Flushed if 1 | ||
| 3: Set if final block of the file* | ||
| 4-7: Reserved for future use |
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Previously, flags were split across two different parts of the file handle entry, because I was lazy. This merges the flags into one byte (since we don't need owner any more) and rearranges them a bit with future changes in mind.
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To identify which thread owned the file. It was necessary when all file handles were in one table, but now that each process is going to have its own file handle table it's not necessary.
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| 0x0000 0x02 Signal handler | ||
| 0x0002 0x01 Signal number | ||
| 0x0003 0x01 Reserved for future use |
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Signals will have to change to be more Unix-like, and some userspace programs may have to change to compensate for this (and some syscalls too). createSignal and readSignal will have to be removed and replaced with signal and kill, which should behave like their POSIX counterparts.
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Lots of places in the kernel (and some places in userspace) have to change for each of these changes. I suggest taking it slowly and breaking this up into smaller changes that you can do and test separately. |
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All references to threads should be replaced with processes. We'll sort something out for distinguishing threads from processes later, it will be something fairly lightweight. Also, threadlist should be changed to use http://www.knightos.org/documentation/reference/threading.html#getNextThreadID instead of accessing kernel memory directly. |
cc @np511
This currently only contains documentation updates.