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Kernel: Rewrite pipes using the new ring buffer

This commit is contained in:
Bananymous 2026-02-28 14:20:52 +02:00
parent 493b5cb9b1
commit 8b8af1a9d9
2 changed files with 17 additions and 37 deletions
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7
kernel/include/kernel/FS/Pipe.h
View File

@ -2,6 +2,7 @@
#include <BAN/Array.h>
#include <kernel/FS/Inode.h>
#include <kernel/Memory/ByteRingBuffer.h>
#include <kernel/ThreadBlocker.h>
namespace Kernel
@ -38,7 +39,7 @@ namespace Kernel
virtual BAN::ErrorOr<size_t> write_impl(off_t, BAN::ConstByteSpan) override;
virtual BAN::ErrorOr<void> fsync_impl() final override { return {}; }
virtual bool can_read_impl() const override { return m_buffer_size > 0; }
virtual bool can_read_impl() const override { return !m_buffer->empty(); }
virtual bool can_write_impl() const override { return true; }
virtual bool has_error_impl() const override { return m_reading_count == 0; }
virtual bool has_hungup_impl() const override { return m_writing_count == 0; }
@ -54,9 +55,7 @@ namespace Kernel
timespec m_ctime {};
ThreadBlocker m_thread_blocker;
BAN::Array<uint8_t, PAGE_SIZE> m_buffer;
BAN::Atomic<size_t> m_buffer_size { 0 };
size_t m_buffer_tail { 0 };
BAN::UniqPtr<ByteRingBuffer> m_buffer;
BAN::Atomic<uint32_t> m_writing_count { 1 };
BAN::Atomic<uint32_t> m_reading_count { 1 };

47
kernel/kernel/FS/Pipe.cpp
View File

@ -9,12 +9,16 @@
namespace Kernel
{
static constexpr size_t s_pipe_buffer_size = 0x10000;
BAN::ErrorOr<BAN::RefPtr<Inode>> Pipe::create(const Credentials& credentials)
{
Pipe* pipe = new Pipe(credentials);
if (pipe == nullptr)
auto* pipe_ptr = new Pipe(credentials);
if (pipe_ptr == nullptr)
return BAN::Error::from_errno(ENOMEM);
return BAN::RefPtr<Inode>::adopt(pipe);
auto pipe = BAN::RefPtr<Pipe>::adopt(pipe_ptr);
pipe->m_buffer = TRY(ByteRingBuffer::create(s_pipe_buffer_size));
return BAN::RefPtr<Inode>(pipe);
}
Pipe::Pipe(const Credentials& credentials)
@ -69,27 +73,16 @@ namespace Kernel
BAN::ErrorOr<size_t> Pipe::read_impl(off_t, BAN::ByteSpan buffer)
{
while (m_buffer_size == 0)
while (m_buffer->empty())
{
if (m_writing_count == 0)
return 0;
TRY(Thread::current().block_or_eintr_indefinite(m_thread_blocker, &m_mutex));
}
const size_t to_copy = BAN::Math::min<size_t>(buffer.size(), m_buffer_size);
if (m_buffer_tail + to_copy <= m_buffer.size())
memcpy(buffer.data(), m_buffer.data() + m_buffer_tail, to_copy);
else
{
const size_t before_wrap = m_buffer.size() - m_buffer_tail;
const size_t after_wrap = to_copy - before_wrap;
memcpy(buffer.data(), m_buffer.data() + m_buffer_tail, before_wrap);
memcpy(buffer.data() + before_wrap, m_buffer.data(), after_wrap);
}
m_buffer_tail = (m_buffer_tail + to_copy) % m_buffer.size();
m_buffer_size -= to_copy;
const size_t to_copy = BAN::Math::min<size_t>(buffer.size(), m_buffer->size());
memcpy(buffer.data(), m_buffer->get_data().data(), to_copy);
m_buffer->pop(to_copy);
m_atime = SystemTimer::get().real_time();
@ -102,7 +95,7 @@ namespace Kernel
BAN::ErrorOr<size_t> Pipe::write_impl(off_t, BAN::ConstByteSpan buffer)
{
while (m_buffer_size >= m_buffer.size())
while (m_buffer->full())
{
if (m_reading_count == 0)
{
@ -112,20 +105,8 @@ namespace Kernel
TRY(Thread::current().block_or_eintr_indefinite(m_thread_blocker, &m_mutex));
}
const size_t to_copy = BAN::Math::min(buffer.size(), m_buffer.size() - m_buffer_size);
const size_t buffer_head = (m_buffer_tail + m_buffer_size) % m_buffer.size();
if (buffer_head + to_copy <= m_buffer.size())
memcpy(m_buffer.data() + buffer_head, buffer.data(), to_copy);
else
{
const size_t before_wrap = m_buffer.size() - buffer_head;
const size_t after_wrap = to_copy - before_wrap;
memcpy(m_buffer.data() + buffer_head, buffer.data(), before_wrap);
memcpy(m_buffer.data(), buffer.data() + before_wrap, after_wrap);
}
m_buffer_size += to_copy;
const size_t to_copy = BAN::Math::min(buffer.size(), m_buffer->free());
m_buffer->push(buffer.slice(0, to_copy));
timespec current_time = SystemTimer::get().real_time();
m_mtime = current_time;