forked from Bananymous/banan-os
Kernel: Rewrite and optimize DiskCache
DiskCache now consists of PageCaches which are caches of contiguous sectors. This allows the disk cache to be ordered and faster traversal. We seem to have a problem somewhere during reading. The stack gets corrupted.
This commit is contained in:
Bananymous
parent
4dce0f9074
commit
0d620f3e0f
|
|
@ -18,30 +18,28 @@ namespace Kernel
|
|||
BAN::ErrorOr<void> read_sector(uint64_t sector, uint8_t* buffer);
|
||||
BAN::ErrorOr<void> write_sector(uint64_t sector, const uint8_t* buffer);
|
||||
|
||||
void sync();
|
||||
size_t release_clean_pages(size_t);
|
||||
size_t release_pages(size_t);
|
||||
void release_all_pages();
|
||||
|
||||
private:
|
||||
struct SectorCache
|
||||
{
|
||||
uint64_t sector { 0 };
|
||||
bool dirty { false };
|
||||
};
|
||||
struct CacheBlock
|
||||
struct PageCache
|
||||
{
|
||||
paddr_t paddr { 0 };
|
||||
BAN::Array<SectorCache, 4> sectors;
|
||||
uint64_t first_sector { 0 };
|
||||
uint8_t sector_mask { 0 };
|
||||
uint8_t dirty_mask { 0 };
|
||||
|
||||
void sync(StorageDevice&);
|
||||
void read_sector(StorageDevice&, size_t, uint8_t*);
|
||||
void write_sector(StorageDevice&, size_t, const uint8_t*);
|
||||
BAN::ErrorOr<void> read_sector(StorageDevice&, uint64_t sector, uint8_t* buffer);
|
||||
BAN::ErrorOr<void> write_sector(StorageDevice&, uint64_t sector, const uint8_t* buffer);
|
||||
};
|
||||
|
||||
private:
|
||||
SpinLock m_lock;
|
||||
StorageDevice& m_device;
|
||||
BAN::Vector<CacheBlock> m_cache;
|
||||
BAN::Vector<PageCache> m_cache;
|
||||
};
|
||||
|
||||
}
|
||||
|
|
@ -13,145 +13,111 @@ namespace Kernel
|
|||
|
||||
DiskCache::~DiskCache()
|
||||
{
|
||||
if (m_device.sector_size() == 0)
|
||||
return;
|
||||
release_all_pages();
|
||||
}
|
||||
|
||||
BAN::ErrorOr<void> DiskCache::read_sector(uint64_t sector, uint8_t* buffer)
|
||||
{
|
||||
LockGuard _(m_lock);
|
||||
|
||||
ASSERT(m_device.sector_size() > 0);
|
||||
ASSERT(m_device.sector_size() <= PAGE_SIZE);
|
||||
|
||||
for (auto& cache_block : m_cache)
|
||||
LockGuard _(m_lock);
|
||||
|
||||
uint64_t sectors_per_page = PAGE_SIZE / m_device.sector_size();
|
||||
ASSERT(sectors_per_page <= sizeof(PageCache::sector_mask) * 8);
|
||||
|
||||
uint64_t page_cache_start = sector / sectors_per_page * sectors_per_page;
|
||||
|
||||
// Check if we already have a cache for this page
|
||||
// FIXME: binary search
|
||||
size_t index = 0;
|
||||
for (; index < m_cache.size(); index++)
|
||||
{
|
||||
for (size_t i = 0; i < cache_block.sectors.size(); i++)
|
||||
{
|
||||
if (cache_block.sectors[i].sector != sector)
|
||||
continue;
|
||||
cache_block.read_sector(m_device, i, buffer);
|
||||
return {};
|
||||
}
|
||||
if (m_cache[index].first_sector < page_cache_start)
|
||||
continue;
|
||||
if (m_cache[index].first_sector > page_cache_start)
|
||||
break;
|
||||
TRY(m_cache[index].read_sector(m_device, sector, buffer));
|
||||
return {};
|
||||
}
|
||||
|
||||
// Sector was not cached so we must read it from disk
|
||||
// Try to allocate new cache
|
||||
if (paddr_t paddr = Heap::get().take_free_page())
|
||||
{
|
||||
MUST(m_cache.insert(index, { .paddr = paddr, .first_sector = page_cache_start }));
|
||||
TRY(m_cache[index].read_sector(m_device, sector, buffer));
|
||||
return {};
|
||||
}
|
||||
|
||||
// Could not allocate new cache, read from disk
|
||||
TRY(m_device.read_sectors_impl(sector, 1, buffer));
|
||||
|
||||
// We try to add the sector to exisiting cache block
|
||||
if (!m_cache.empty())
|
||||
{
|
||||
auto& cache_block = m_cache.back();
|
||||
for (size_t i = 0; i < m_cache.back().sectors.size(); i++)
|
||||
{
|
||||
if (cache_block.sectors[i].sector)
|
||||
continue;
|
||||
cache_block.write_sector(m_device, i, buffer);
|
||||
cache_block.sectors[i].sector = sector;
|
||||
cache_block.sectors[i].dirty = false;
|
||||
return {};
|
||||
}
|
||||
}
|
||||
|
||||
// We try to allocate new cache block for this sector
|
||||
if (!m_cache.emplace_back().is_error())
|
||||
{
|
||||
if (paddr_t paddr = Heap::get().take_free_page())
|
||||
{
|
||||
auto& cache_block = m_cache.back();
|
||||
cache_block.paddr = paddr;
|
||||
cache_block.write_sector(m_device, 0, buffer);
|
||||
cache_block.sectors[0].sector = sector;
|
||||
cache_block.sectors[0].dirty = false;
|
||||
return {};
|
||||
}
|
||||
m_cache.pop_back();
|
||||
}
|
||||
|
||||
// We could not cache the sector
|
||||
return {};
|
||||
}
|
||||
|
||||
BAN::ErrorOr<void> DiskCache::write_sector(uint64_t sector, const uint8_t* buffer)
|
||||
{
|
||||
LockGuard _(m_lock);
|
||||
|
||||
ASSERT(m_device.sector_size() > 0);
|
||||
ASSERT(m_device.sector_size() <= PAGE_SIZE);
|
||||
|
||||
// Try to find this sector in the cache
|
||||
for (auto& cache_block : m_cache)
|
||||
LockGuard _(m_lock);
|
||||
|
||||
uint64_t sectors_per_page = PAGE_SIZE / m_device.sector_size();
|
||||
ASSERT(sectors_per_page <= sizeof(PageCache::sector_mask) * 8);
|
||||
|
||||
uint64_t page_cache_start = sector / sectors_per_page * sectors_per_page;
|
||||
|
||||
// Check if we already have a cache for this page
|
||||
// FIXME: binary search
|
||||
size_t index = 0;
|
||||
for (; index < m_cache.size(); index++)
|
||||
{
|
||||
for (size_t i = 0; i < cache_block.sectors.size(); i++)
|
||||
{
|
||||
if (cache_block.sectors[i].sector != sector)
|
||||
continue;
|
||||
cache_block.write_sector(m_device, i, buffer);
|
||||
cache_block.sectors[i].dirty = true;
|
||||
return {};
|
||||
}
|
||||
if (m_cache[index].first_sector < page_cache_start)
|
||||
continue;
|
||||
if (m_cache[index].first_sector > page_cache_start)
|
||||
break;
|
||||
TRY(m_cache[index].write_sector(m_device, sector, buffer));
|
||||
return {};
|
||||
}
|
||||
|
||||
// Sector was not in the cache, we try to add it to exisiting cache block
|
||||
if (!m_cache.empty())
|
||||
// Try to allocate new cache
|
||||
if (paddr_t paddr = Heap::get().take_free_page())
|
||||
{
|
||||
auto& cache_block = m_cache.back();
|
||||
for (size_t i = 0; i < m_cache.back().sectors.size(); i++)
|
||||
{
|
||||
if (cache_block.sectors[i].sector)
|
||||
continue;
|
||||
cache_block.write_sector(m_device, i, buffer);
|
||||
cache_block.sectors[i].sector = sector;
|
||||
cache_block.sectors[i].dirty = true;
|
||||
return {};
|
||||
}
|
||||
MUST(m_cache.insert(index, { .paddr = paddr, .first_sector = page_cache_start }));
|
||||
TRY(m_cache[index].write_sector(m_device, sector, buffer));
|
||||
return {};
|
||||
}
|
||||
|
||||
// We try to allocate new cache block
|
||||
if (!m_cache.emplace_back().is_error())
|
||||
{
|
||||
if (paddr_t paddr = Heap::get().take_free_page())
|
||||
{
|
||||
auto& cache_block = m_cache.back();
|
||||
cache_block.paddr = paddr;
|
||||
cache_block.write_sector(m_device, 0, buffer);
|
||||
cache_block.sectors[0].sector = sector;
|
||||
cache_block.sectors[0].dirty = true;
|
||||
return {};
|
||||
}
|
||||
m_cache.pop_back();
|
||||
}
|
||||
|
||||
// We could not allocate cache, so we must sync it to disk
|
||||
// right away
|
||||
// Could not allocate new cache, write to disk
|
||||
TRY(m_device.write_sectors_impl(sector, 1, buffer));
|
||||
return {};
|
||||
}
|
||||
|
||||
void DiskCache::sync()
|
||||
{
|
||||
ASSERT(m_device.sector_size() <= PAGE_SIZE);
|
||||
|
||||
LockGuard _(m_lock);
|
||||
for (auto& cache_block : m_cache)
|
||||
cache_block.sync(m_device);
|
||||
}
|
||||
|
||||
size_t DiskCache::release_clean_pages(size_t page_count)
|
||||
{
|
||||
LockGuard _(m_lock);
|
||||
|
||||
ASSERT(m_device.sector_size() > 0);
|
||||
ASSERT(m_device.sector_size() <= PAGE_SIZE);
|
||||
|
||||
// NOTE: There might not actually be page_count pages after this
|
||||
// function returns. The synchronization must be done elsewhere.
|
||||
LockGuard _(m_lock);
|
||||
|
||||
size_t released = 0;
|
||||
for (size_t i = 0; i < m_cache.size() && released < page_count;)
|
||||
{
|
||||
bool dirty = false;
|
||||
for (size_t j = 0; j < sizeof(m_cache[i].sectors) / sizeof(SectorCache); j++)
|
||||
if (m_cache[i].sectors[j].dirty)
|
||||
dirty = true;
|
||||
if (dirty)
|
||||
if (m_cache[i].dirty_mask == 0)
|
||||
{
|
||||
i++;
|
||||
Heap::get().release_page(m_cache[i].paddr);
|
||||
m_cache.remove(i);
|
||||
released++;
|
||||
continue;
|
||||
}
|
||||
|
||||
Heap::get().release_page(m_cache[i].paddr);
|
||||
m_cache.remove(i);
|
||||
released++;
|
||||
i++;
|
||||
}
|
||||
|
||||
(void)m_cache.shrink_to_fit();
|
||||
|
|
@ -161,12 +127,11 @@ namespace Kernel
|
|||
|
||||
size_t DiskCache::release_pages(size_t page_count)
|
||||
{
|
||||
ASSERT(m_device.sector_size() > 0);
|
||||
ASSERT(m_device.sector_size() <= PAGE_SIZE);
|
||||
|
||||
size_t released = release_clean_pages(page_count);
|
||||
if (released >= page_count)
|
||||
return page_count;
|
||||
return released;
|
||||
|
||||
// NOTE: There might not actually be page_count pages after this
|
||||
// function returns. The synchronization must be done elsewhere.
|
||||
|
|
@ -187,13 +152,9 @@ namespace Kernel
|
|||
|
||||
void DiskCache::release_all_pages()
|
||||
{
|
||||
LockGuard _(m_lock);
|
||||
|
||||
ASSERT(m_device.sector_size() > 0);
|
||||
ASSERT(m_device.sector_size() <= PAGE_SIZE);
|
||||
|
||||
uint8_t* temp_buffer = (uint8_t*)kmalloc(m_device.sector_size());
|
||||
ASSERT(temp_buffer);
|
||||
LockGuard _(m_lock);
|
||||
|
||||
for (auto& cache_block : m_cache)
|
||||
{
|
||||
|
|
@ -204,51 +165,97 @@ namespace Kernel
|
|||
m_cache.clear();
|
||||
}
|
||||
|
||||
void DiskCache::CacheBlock::sync(StorageDevice& device)
|
||||
void DiskCache::PageCache::sync(StorageDevice& device)
|
||||
{
|
||||
uint8_t* temp_buffer = (uint8_t*)kmalloc(device.sector_size());
|
||||
ASSERT(temp_buffer);
|
||||
if (this->dirty_mask == 0)
|
||||
return;
|
||||
|
||||
for (size_t i = 0; i < sectors.size(); i++)
|
||||
ASSERT(device.sector_size() <= PAGE_SIZE);
|
||||
|
||||
PageTable& page_table = PageTable::current();
|
||||
|
||||
page_table.lock();
|
||||
ASSERT(page_table.is_page_free(0));
|
||||
|
||||
page_table.map_page_at(this->paddr, 0, PageTable::Flags::ReadWrite | PageTable::Flags::Present);
|
||||
page_table.invalidate(0);
|
||||
|
||||
for (size_t i = 0; i < PAGE_SIZE / device.sector_size(); i++)
|
||||
{
|
||||
if (!sectors[i].dirty)
|
||||
if (!(this->dirty_mask & (1 << i)))
|
||||
continue;
|
||||
read_sector(device, i, temp_buffer);
|
||||
MUST(device.write_sectors_impl(sectors[i].sector, 1, temp_buffer));
|
||||
sectors[i].dirty = false;
|
||||
MUST(device.write_sectors_impl(this->first_sector + i, 1, (const uint8_t*)(i * device.sector_size())));
|
||||
}
|
||||
|
||||
kfree(temp_buffer);
|
||||
page_table.unmap_page(0);
|
||||
page_table.invalidate(0);
|
||||
|
||||
page_table.unlock();
|
||||
|
||||
this->dirty_mask = 0;
|
||||
}
|
||||
|
||||
void DiskCache::CacheBlock::read_sector(StorageDevice& device, size_t index, uint8_t* buffer)
|
||||
BAN::ErrorOr<void> DiskCache::PageCache::read_sector(StorageDevice& device, uint64_t sector, uint8_t* buffer)
|
||||
{
|
||||
ASSERT(index < sectors.size());
|
||||
ASSERT(device.sector_size() <= PAGE_SIZE);
|
||||
|
||||
uint64_t sectors_per_page = PAGE_SIZE / device.sector_size();
|
||||
uint64_t sector_offset = sector - this->first_sector;
|
||||
|
||||
ASSERT(sector_offset < sectors_per_page);
|
||||
|
||||
PageTable& page_table = PageTable::current();
|
||||
|
||||
page_table.lock();
|
||||
ASSERT(page_table.is_page_free(0));
|
||||
page_table.map_page_at(paddr, 0, PageTable::Flags::Present);
|
||||
memcpy(buffer, (void*)(index * device.sector_size()), device.sector_size());
|
||||
|
||||
page_table.map_page_at(this->paddr, 0, PageTable::Flags::ReadWrite | PageTable::Flags::Present);
|
||||
page_table.invalidate(0);
|
||||
|
||||
// Sector not yet cached
|
||||
if (!(this->sector_mask & (1 << sector_offset)))
|
||||
{
|
||||
TRY(device.read_sectors_impl(sector, 1, (uint8_t*)(sector_offset * device.sector_size())));
|
||||
this->sector_mask |= 1 << sector_offset;
|
||||
}
|
||||
|
||||
memcpy(buffer, (const void*)(sector_offset * device.sector_size()), device.sector_size());
|
||||
|
||||
page_table.unmap_page(0);
|
||||
page_table.invalidate(0);
|
||||
|
||||
page_table.unlock();
|
||||
|
||||
return {};
|
||||
}
|
||||
|
||||
void DiskCache::CacheBlock::write_sector(StorageDevice& device, size_t index, const uint8_t* buffer)
|
||||
BAN::ErrorOr<void> DiskCache::PageCache::write_sector(StorageDevice& device, uint64_t sector, const uint8_t* buffer)
|
||||
{
|
||||
ASSERT(index < sectors.size());
|
||||
ASSERT(device.sector_size() <= PAGE_SIZE);
|
||||
|
||||
uint64_t sectors_per_page = PAGE_SIZE / device.sector_size();
|
||||
uint64_t sector_offset = sector - this->first_sector;
|
||||
|
||||
ASSERT(sector_offset < sectors_per_page);
|
||||
|
||||
PageTable& page_table = PageTable::current();
|
||||
|
||||
page_table.lock();
|
||||
ASSERT(page_table.is_page_free(0));
|
||||
page_table.map_page_at(paddr, 0, PageTable::Flags::ReadWrite | PageTable::Flags::Present);
|
||||
memcpy((void*)(index * device.sector_size()), buffer, device.sector_size());
|
||||
|
||||
page_table.map_page_at(this->paddr, 0, PageTable::Flags::ReadWrite | PageTable::Flags::Present);
|
||||
page_table.invalidate(0);
|
||||
|
||||
memcpy((void*)(sector_offset * device.sector_size()), buffer, device.sector_size());
|
||||
this->sector_mask |= 1 << sector_offset;
|
||||
this->dirty_mask |= 1 << sector_offset;
|
||||
|
||||
page_table.unmap_page(0);
|
||||
page_table.invalidate(0);
|
||||
|
||||
page_table.unlock();
|
||||
|
||||
return {};
|
||||
}
|
||||
|
||||
}
|
||||
Loading…
Reference in New Issue