Commit graph

13 commits

Author SHA1 Message Date
Andreas Kling
f2846e8e08 Kernel: Allow short writes to DoubleBuffer
DoubleBuffer is the internal buffer for things like TTY, FIFO, sockets,
etc. If you try to write more than the buffer can hold, it will now
do a short write instead of asserting.

This is likely to expose issues at higher levels, and we'll have to
deal with them as they are discovered.
2020-02-01 10:56:17 +01:00
Andreas Kling
f4f958f99f Kernel: Make DoubleBuffer use a KBuffer instead of kmalloc()ing
Background: DoubleBuffer is a handy buffer class in the kernel that
allows you to keep writing to it from the "outside" while the "inside"
reads from it. It's used for things like LocalSocket and TTY's.
Internally, it has a read buffer and a write buffer, but the two will
swap places when the read buffer is exhausted (by reading from it.)

Before this patch, it was internally implemented as two Vector<u8>
that we would swap between when the reader side had exhausted the data
in the read buffer. Now instead we preallocate a large KBuffer (64KB*2)
on DoubleBuffer construction and use that throughout its lifetime.

This removes all the kmalloc heap traffic caused by DoubleBuffers :^)
2020-01-20 16:08:49 +01:00
Andreas Kling
94ca55cefd Meta: Add license header to source files
As suggested by Joshua, this commit adds the 2-clause BSD license as a
comment block to the top of every source file.

For the first pass, I've just added myself for simplicity. I encourage
everyone to add themselves as copyright holders of any file they've
added or modified in some significant way. If I've added myself in
error somewhere, feel free to replace it with the appropriate copyright
holder instead.

Going forward, all new source files should include a license header.
2020-01-18 09:45:54 +01:00
Andreas Kling
ec65b8db2e Revert "Kernel: Make DoubleBuffer use a KBuffer instead of kmalloc()ing"
This reverts commit 1cca5142af.

This appears to be causing intermittent triple-faults and I don't know
why yet, so I'll just revert it to keep the tree in decent shape.
2019-10-18 15:58:06 +02:00
Andreas Kling
1cca5142af Kernel: Make DoubleBuffer use a KBuffer instead of kmalloc()ing
Background: DoubleBuffer is a handy buffer class in the kernel that
allows you to keep writing to it from the "outside" while the "inside"
reads from it. It's used for things like LocalSocket and PTY's.
Internally, it has a read buffer and a write buffer, but the two will
swap places when the read buffer is exhausted (by reading from it.)

Before this patch, it was internally implemented as two Vector<u8>
that we would swap between when the reader side had exhausted the data
in the read buffer. Now instead we preallocate a large KBuffer (64KB*2)
on DoubleBuffer construction and use that throughout its lifetime.

This removes all the kmalloc heap traffic caused by DoubleBuffers :^)
2019-10-18 14:55:04 +02:00
Andreas Kling
27f699ef0c AK: Rename the common integer typedefs to make it obvious what they are.
These types can be picked up by including <AK/Types.h>:

* u8, u16, u32, u64 (unsigned)
* i8, i16, i32, i64 (signed)
2019-07-03 21:20:13 +02:00
Andreas Kling
a02c945ef2 Kernel: DoubleBuffer can return early if read/write is called with !size. 2019-03-20 02:12:40 +01:00
Andreas Kling
beda478821 Kernel: Make syscalls that take a buffer size use ssize_t instead of size_t.
Dealing with the unsigned overflow propagation here just seems unreasonably
error prone. Let's limit ourselves to 2GB buffer sizes instead.
2019-02-25 21:21:12 +01:00
Andreas Kling
9c51d9dfcd Catch anyone trying to use a DoubleBuffer with interrupts disabled. 2019-01-16 01:58:11 +01:00
Andreas Kling
52c004eb53 Add internal locking to DoubleBuffer. 2019-01-15 21:43:38 +01:00
Andreas Kling
3ac977f50b Paper over a race in DoubleBuffer.
I'm still somewhat okay throwing InterruptDisabler at races as they screw me.
Eventually I'm gonna have to devise a different strategy though.
2019-01-12 23:23:35 +01:00
Andreas Kling
ec1c487dcd Yet another pass of style fixes. 2018-12-21 02:10:45 +01:00
Andreas Kling
bbfae19238 Move DoubleBuffer to its own files. 2018-12-03 01:51:44 +01:00