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Implement multi-page allocations in buddy allocator (poorly)

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This commit is contained in:
Jeremy Soller
2020-09-09 16:02:44 -06:00
parent 711414223b
commit 0c44dde349
1 changed files with 69 additions and 14 deletions
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src/allocator/frame/buddy.rs
+69 -14
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@@ -131,34 +131,49 @@ impl<A: Arch> BuddyAllocator<A> {
impl<A: Arch> FrameAllocator for BuddyAllocator<A> {
unsafe fn allocate(&mut self, count: FrameCount) -> Option<PhysicalAddress> {
//TODO: support other sizes
if self.table_virt.data() == 0 || count.data() != 1 {
if self.table_virt.data() == 0 {
return None;
}
for i in 0 .. Self::BUDDY_ENTRIES {
let virt = self.table_virt.add(i * mem::size_of::<BuddyEntry>());
for entry_i in 0 .. Self::BUDDY_ENTRIES {
let virt = self.table_virt.add(entry_i * mem::size_of::<BuddyEntry>());
let entry = A::read::<BuddyEntry>(virt);
let mut start_map_phys = entry.map;
let mut start_offset = 0;
let mut start_i = 0;
let mut start_bit = 0;
let mut start_page_phys = PhysicalAddress::new(0);
let mut found = 0;
//TODO: improve performance
let mut map_phys = entry.map;
let mut offset = 0;
while map_phys.data() != 0 {
let mut map_phys = start_map_phys;
let mut offset = start_offset;
'find: while map_phys.data() != 0 {
let map_virt = A::phys_to_virt(map_phys);
for i in 0 .. Self::MAP_PAGE_BYTES {
let map_byte_virt = map_virt.add(i);
let mut value: u8 = A::read(map_byte_virt);
let value: u8 = A::read(map_byte_virt);
if (value & u8::MAX) != 0 {
for bit in 0..8 {
if (value & (1 << bit)) != 0 {
value &= !(1 << bit);
A::write(map_byte_virt, value);
let page_phys = entry.base.add(offset + bit * A::PAGE_SIZE);
let page_virt = A::phys_to_virt(page_phys);
A::write_bytes(page_virt, 0, A::PAGE_SIZE);
return Some(page_phys);
if found == 0 {
start_map_phys = map_phys;
start_offset = offset;
start_i = i;
start_bit = bit;
start_page_phys = entry.base.add(offset + bit * A::PAGE_SIZE);
}
found += 1;
if found == count.data() {
break 'find;
}
} else {
found = 0;
}
}
} else {
found = 0;
}
offset += A::PAGE_SIZE * 8;
}
@@ -166,6 +181,46 @@ impl<A: Arch> FrameAllocator for BuddyAllocator<A> {
let footer = A::read::<BuddyMapFooter>(map_virt.add(Self::MAP_PAGE_BYTES));
map_phys = footer.next;
}
if found == count.data() {
map_phys = start_map_phys;
offset = start_offset;
found = 0;
while map_phys.data() != 0 {
let map_virt = A::phys_to_virt(map_phys);
for i in start_i .. Self::MAP_PAGE_BYTES {
let map_byte_virt = map_virt.add(i);
let mut value: u8 = A::read(map_byte_virt);
if (value & u8::MAX) != 0 {
for bit in start_bit..8 {
if (value & (1 << bit)) != 0 {
value &= !(1 << bit);
A::write(map_byte_virt, value);
let page_phys = entry.base.add(offset + bit * A::PAGE_SIZE);
let page_virt = A::phys_to_virt(page_phys);
A::write_bytes(page_virt, 0, A::PAGE_SIZE);
found += 1;
if found == count.data() {
return Some(start_page_phys);
}
} else {
panic!("check your logic, bit was set");
}
}
start_bit = 0;
} else {
panic!("check your logic, byte was set");
}
offset += A::PAGE_SIZE * 8;
}
start_i = 0;
let footer = A::read::<BuddyMapFooter>(map_virt.add(Self::MAP_PAGE_BYTES));
map_phys = footer.next;
}
}
}
None
}