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common/host_memory: Optimize for huge tables.

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In theory, if we have 2 MB continously mapped, this should save one layer of TLB.
Let's make it at least more likely by aligning the memory.
This commit is contained in:
Markus Wick 2021-06-05 11:47:08 +02:00
parent 621f3f5f47
commit c4609c92ee
2 changed files with 24 additions and 11 deletions
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29
src/common/host_memory.cpp
View file

@ -27,6 +27,7 @@
#include <mutex>
#include "common/alignment.h"
#include "common/assert.h"
#include "common/host_memory.h"
#include "common/logging/log.h"
@ -35,6 +36,7 @@
namespace Common {
constexpr size_t PageAlignment = 0x1000;
constexpr size_t HugePageSize = 0x200000;
#ifdef _WIN32
@ -385,9 +387,16 @@ private:
#endif
HostMemory::HostMemory(size_t backing_size, size_t virtual_size)
: impl{std::make_unique<HostMemory::Impl>(backing_size, virtual_size)},
backing_base{impl->backing_base}, virtual_base{impl->virtual_base} {}
HostMemory::HostMemory(size_t backing_size_, size_t virtual_size_)
: backing_size(backing_size_),
virtual_size(virtual_size_), impl{std::make_unique<HostMemory::Impl>(
AlignUp(backing_size, PageAlignment),
AlignUp(virtual_size, PageAlignment) + 3 * HugePageSize)},
backing_base{impl->backing_base}, virtual_base{impl->virtual_base} {
virtual_base += 2 * HugePageSize - 1;
virtual_base -= reinterpret_cast<size_t>(virtual_base) & (HugePageSize - 1);
virtual_base_offset = virtual_base - impl->virtual_base;
}
HostMemory::~HostMemory() = default;
@ -399,32 +408,32 @@ void HostMemory::Map(size_t virtual_offset, size_t host_offset, size_t length) {
ASSERT(virtual_offset % PageAlignment == 0);
ASSERT(host_offset % PageAlignment == 0);
ASSERT(length % PageAlignment == 0);
ASSERT(virtual_offset + length <= impl->virtual_size);
ASSERT(host_offset + length <= impl->backing_size);
ASSERT(virtual_offset + length <= virtual_size);
ASSERT(host_offset + length <= backing_size);
if (length == 0) {
return;
}
impl->Map(virtual_offset, host_offset, length);
impl->Map(virtual_offset + virtual_base_offset, host_offset, length);
}
void HostMemory::Unmap(size_t virtual_offset, size_t length) {
ASSERT(virtual_offset % PageAlignment == 0);
ASSERT(length % PageAlignment == 0);
ASSERT(virtual_offset + length <= impl->virtual_size);
ASSERT(virtual_offset + length <= virtual_size);
if (length == 0) {
return;
}
impl->Unmap(virtual_offset, length);
impl->Unmap(virtual_offset + virtual_base_offset, length);
}
void HostMemory::Protect(size_t virtual_offset, size_t length, bool read, bool write) {
ASSERT(virtual_offset % PageAlignment == 0);
ASSERT(length % PageAlignment == 0);
ASSERT(virtual_offset + length <= impl->virtual_size);
ASSERT(virtual_offset + length <= virtual_size);
if (length == 0) {
return;
}
impl->Protect(virtual_offset, length, read, write);
impl->Protect(virtual_offset + virtual_base_offset, length, read, write);
}
} // namespace Common

6
src/common/host_memory.h
View file

@ -15,7 +15,7 @@ namespace Common {
*/
class HostMemory {
public:
explicit HostMemory(size_t backing_size, size_t virtual_size);
explicit HostMemory(size_t backing_size_, size_t virtual_size_);
~HostMemory();
/**
@ -52,11 +52,15 @@ public:
}
private:
size_t backing_size{};
size_t virtual_size{};
// Low level handler for the platform dependent memory routines
class Impl;
std::unique_ptr<Impl> impl;
u8* backing_base{};
u8* virtual_base{};
size_t virtual_base_offset{};
};
} // namespace Common