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Free surplus unused bcache blocks.

This commit is contained in:
Jonas 'Sortie' Termansen 2013-03-12 17:41:25 +01:00
parent 9434ee94fd
commit ce66539ff7
2 changed files with 25 additions and 0 deletions
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23
sortix/fcache.cpp
View File

@ -84,6 +84,7 @@ BlockCache::BlockCache()
areas_used = 0;
areas_length = 0;
blocks_per_area = 1024UL;
unused_block_count = 0;
mru_block = NULL;
lru_block = NULL;
unused_block = NULL;
@ -102,6 +103,7 @@ BlockCacheBlock* BlockCache::AcquireBlock()
return NULL;
BlockCacheBlock* ret = unused_block;
assert(ret);
unused_block_count--;
unused_block = unused_block->next_block;
ret->prev_block = ret->next_block = NULL;
if ( unused_block )
@ -114,7 +116,22 @@ BlockCacheBlock* BlockCache::AcquireBlock()
void BlockCache::ReleaseBlock(BlockCacheBlock* block)
{
ScopedLock lock(&bcache_mutex);
assert(block->information & BCACHE_PRESENT);
assert(block->information & BCACHE_USED);
if ( blocks_per_area < unused_block_count )
{
uint8_t* block_data = BlockDataUnlocked(block);
addr_t block_data_addr = Memory::Unmap((addr_t) block_data);
Page::Put(block_data_addr);
// TODO: We leak this block's meta information here. Rather, we should
// put this block into a list of non-present blocks so we can reuse it
// later and reallocate a physical frame for it - then we will just
// reuse the block's meta information.
block->information &= ~(BCACHE_USED | BCACHE_PRESENT);
return;
}
UnlinkBlock(block);
unused_block_count++;
if ( unused_block )
unused_block->prev_block = block;
block->next_block = unused_block;
@ -126,6 +143,11 @@ void BlockCache::ReleaseBlock(BlockCacheBlock* block)
uint8_t* BlockCache::BlockData(BlockCacheBlock* block)
{
ScopedLock lock(&bcache_mutex);
return BlockDataUnlocked(block);
}
uint8_t* BlockCache::BlockDataUnlocked(BlockCacheBlock* block)
{
uintptr_t block_id = BlockIdOfBlockInformation(block->information);
uintptr_t area_num = AreaOfBlockId(block_id, blocks_per_area);
uintptr_t area_off = BlockOfBlockId(block_id, blocks_per_area);
@ -206,6 +228,7 @@ bool BlockCache::AddArea()
if ( unused_block )
unused_block->prev_block = block;
unused_block = block;
unused_block_count++;
}
area->data = (uint8_t*) area->addralloc.from;

2
sortix/include/sortix/kernel/fcache.h
View File

@ -59,12 +59,14 @@ public:
bool AddArea();
void UnlinkBlock(BlockCacheBlock* block);
void LinkBlock(BlockCacheBlock* block);
uint8_t* BlockDataUnlocked(BlockCacheBlock* block);
private:
BlockCacheArea* areas;
size_t areas_used;
size_t areas_length;
size_t blocks_per_area;
size_t unused_block_count;
BlockCacheBlock* mru_block;
BlockCacheBlock* lru_block;
BlockCacheBlock* unused_block;