ryujinx/Ryujinx.Memory/Tracking/MemoryTracking.cs
riperiperi 3d98e1361b
GPU: Use a bitmap to track buffer modified flags. (#3775)
* Initial implementation

* Some improvements.

* Fix incorrect cast

* Performance improvement and improved correctness

* Add very fast path when all handles are checked.

* Slightly faster

* Add comment

* De-virtualize region handle

All region handles are now bitmap backed.

* Remove non-bitmap tracking

* Remove unused methods

* Add docs, remove unused methods

* Address Feedback

* Rename file
2022-10-29 22:07:37 +00:00

301 lines
13 KiB
C#

using Ryujinx.Common.Pools;
using Ryujinx.Memory.Range;
using System.Collections.Generic;
namespace Ryujinx.Memory.Tracking
{
/// <summary>
/// Manages memory tracking for a given virutal/physical memory block.
/// </summary>
public class MemoryTracking
{
private readonly IVirtualMemoryManager _memoryManager;
private readonly InvalidAccessHandler _invalidAccessHandler;
// Only use these from within the lock.
private readonly NonOverlappingRangeList<VirtualRegion> _virtualRegions;
private readonly int _pageSize;
/// <summary>
/// This lock must be obtained when traversing or updating the region-handle hierarchy.
/// It is not required when reading dirty flags.
/// </summary>
internal object TrackingLock = new object();
/// <summary>
/// Create a new tracking structure for the given "physical" memory block,
/// with a given "virtual" memory manager that will provide mappings and virtual memory protection.
/// </summary>
/// <param name="memoryManager">Virtual memory manager</param>
/// <param name="block">Physical memory block</param>
/// <param name="pageSize">Page size of the virtual memory space</param>
public MemoryTracking(IVirtualMemoryManager memoryManager, int pageSize, InvalidAccessHandler invalidAccessHandler = null)
{
_memoryManager = memoryManager;
_pageSize = pageSize;
_invalidAccessHandler = invalidAccessHandler;
_virtualRegions = new NonOverlappingRangeList<VirtualRegion>();
}
private (ulong address, ulong size) PageAlign(ulong address, ulong size)
{
ulong pageMask = (ulong)_pageSize - 1;
ulong rA = address & ~pageMask;
ulong rS = ((address + size + pageMask) & ~pageMask) - rA;
return (rA, rS);
}
/// <summary>
/// Indicate that a virtual region has been mapped, and which physical region it has been mapped to.
/// Should be called after the mapping is complete.
/// </summary>
/// <param name="va">Virtual memory address</param>
/// <param name="size">Size to be mapped</param>
public void Map(ulong va, ulong size)
{
// A mapping may mean we need to re-evaluate each VirtualRegion's affected area.
// Find all handles that overlap with the range, we need to recalculate their physical regions
lock (TrackingLock)
{
ref var overlaps = ref ThreadStaticArray<VirtualRegion>.Get();
int count = _virtualRegions.FindOverlapsNonOverlapping(va, size, ref overlaps);
for (int i = 0; i < count; i++)
{
VirtualRegion region = overlaps[i];
// If the region has been fully remapped, signal that it has been mapped again.
bool remapped = _memoryManager.IsRangeMapped(region.Address, region.Size);
if (remapped)
{
region.SignalMappingChanged(true);
}
region.UpdateProtection();
}
}
}
/// <summary>
/// Indicate that a virtual region has been unmapped.
/// Should be called before the unmapping is complete.
/// </summary>
/// <param name="va">Virtual memory address</param>
/// <param name="size">Size to be unmapped</param>
public void Unmap(ulong va, ulong size)
{
// An unmapping may mean we need to re-evaluate each VirtualRegion's affected area.
// Find all handles that overlap with the range, we need to notify them that the region was unmapped.
lock (TrackingLock)
{
ref var overlaps = ref ThreadStaticArray<VirtualRegion>.Get();
int count = _virtualRegions.FindOverlapsNonOverlapping(va, size, ref overlaps);
for (int i = 0; i < count; i++)
{
VirtualRegion region = overlaps[i];
region.SignalMappingChanged(false);
}
}
}
/// <summary>
/// Get a list of virtual regions that a handle covers.
/// </summary>
/// <param name="va">Starting virtual memory address of the handle</param>
/// <param name="size">Size of the handle's memory region</param>
/// <returns>A list of virtual regions within the given range</returns>
internal List<VirtualRegion> GetVirtualRegionsForHandle(ulong va, ulong size)
{
List<VirtualRegion> result = new List<VirtualRegion>();
_virtualRegions.GetOrAddRegions(result, va, size, (va, size) => new VirtualRegion(this, va, size));
return result;
}
/// <summary>
/// Remove a virtual region from the range list. This assumes that the lock has been acquired.
/// </summary>
/// <param name="region">Region to remove</param>
internal void RemoveVirtual(VirtualRegion region)
{
_virtualRegions.Remove(region);
}
/// <summary>
/// Obtains a memory tracking handle for the given virtual region, with a specified granularity. This should be disposed when finished with.
/// </summary>
/// <param name="address">CPU virtual address of the region</param>
/// <param name="size">Size of the region</param>
/// <param name="handles">Handles to inherit state from or reuse. When none are present, provide null</param>
/// <param name="granularity">Desired granularity of write tracking</param>
/// <returns>The memory tracking handle</returns>
public MultiRegionHandle BeginGranularTracking(ulong address, ulong size, IEnumerable<IRegionHandle> handles, ulong granularity)
{
(address, size) = PageAlign(address, size);
return new MultiRegionHandle(this, address, size, handles, granularity);
}
/// <summary>
/// Obtains a smart memory tracking handle for the given virtual region, with a specified granularity. This should be disposed when finished with.
/// </summary>
/// <param name="address">CPU virtual address of the region</param>
/// <param name="size">Size of the region</param>
/// <param name="granularity">Desired granularity of write tracking</param>
/// <returns>The memory tracking handle</returns>
public SmartMultiRegionHandle BeginSmartGranularTracking(ulong address, ulong size, ulong granularity)
{
(address, size) = PageAlign(address, size);
return new SmartMultiRegionHandle(this, address, size, granularity);
}
/// <summary>
/// Obtains a memory tracking handle for the given virtual region. This should be disposed when finished with.
/// </summary>
/// <param name="address">CPU virtual address of the region</param>
/// <param name="size">Size of the region</param>
/// <returns>The memory tracking handle</returns>
public RegionHandle BeginTracking(ulong address, ulong size)
{
(address, size) = PageAlign(address, size);
lock (TrackingLock)
{
RegionHandle handle = new RegionHandle(this, address, size, _memoryManager.IsRangeMapped(address, size));
return handle;
}
}
/// <summary>
/// Obtains a memory tracking handle for the given virtual region. This should be disposed when finished with.
/// </summary>
/// <param name="address">CPU virtual address of the region</param>
/// <param name="size">Size of the region</param>
/// <param name="bitmap">The bitmap owning the dirty flag for this handle</param>
/// <param name="bit">The bit of this handle within the dirty flag</param>
/// <returns>The memory tracking handle</returns>
internal RegionHandle BeginTrackingBitmap(ulong address, ulong size, ConcurrentBitmap bitmap, int bit)
{
(address, size) = PageAlign(address, size);
lock (TrackingLock)
{
RegionHandle handle = new RegionHandle(this, address, size, bitmap, bit, _memoryManager.IsRangeMapped(address, size));
return handle;
}
}
/// <summary>
/// Signal that a virtual memory event happened at the given location (one byte).
/// </summary>
/// <param name="address">Virtual address accessed</param>
/// <param name="write">Whether the address was written to or read</param>
/// <returns>True if the event triggered any tracking regions, false otherwise</returns>
public bool VirtualMemoryEventTracking(ulong address, bool write)
{
return VirtualMemoryEvent(address, 1, write);
}
/// <summary>
/// Signal that a virtual memory event happened at the given location.
/// This can be flagged as a precise event, which will avoid reprotection and call special handlers if possible.
/// A precise event has an exact address and size, rather than triggering on page granularity.
/// </summary>
/// <param name="address">Virtual address accessed</param>
/// <param name="size">Size of the region affected in bytes</param>
/// <param name="write">Whether the region was written to or read</param>
/// <param name="precise">True if the access is precise, false otherwise</param>
/// <returns>True if the event triggered any tracking regions, false otherwise</returns>
public bool VirtualMemoryEvent(ulong address, ulong size, bool write, bool precise = false)
{
// Look up the virtual region using the region list.
// Signal up the chain to relevant handles.
bool shouldThrow = false;
lock (TrackingLock)
{
ref var overlaps = ref ThreadStaticArray<VirtualRegion>.Get();
int count = _virtualRegions.FindOverlapsNonOverlapping(address, size, ref overlaps);
if (count == 0 && !precise)
{
if (_memoryManager.IsRangeMapped(address, size))
{
// TODO: There is currently the possibility that a page can be protected after its virtual region is removed.
// This code handles that case when it happens, but it would be better to find out how this happens.
_memoryManager.TrackingReprotect(address & ~(ulong)(_pageSize - 1), (ulong)_pageSize, MemoryPermission.ReadAndWrite);
return true; // This memory _should_ be mapped, so we need to try again.
}
else
{
shouldThrow = true;
}
}
else
{
for (int i = 0; i < count; i++)
{
VirtualRegion region = overlaps[i];
if (precise)
{
region.SignalPrecise(address, size, write);
}
else
{
region.Signal(address, size, write);
}
}
}
}
if (shouldThrow)
{
_invalidAccessHandler?.Invoke(address);
// We can't continue - it's impossible to remove protection from the page.
// Even if the access handler wants us to continue, we wouldn't be able to.
throw new InvalidMemoryRegionException();
}
return true;
}
/// <summary>
/// Reprotect a given virtual region. The virtual memory manager will handle this.
/// </summary>
/// <param name="region">Region to reprotect</param>
/// <param name="permission">Memory permission to protect with</param>
internal void ProtectVirtualRegion(VirtualRegion region, MemoryPermission permission)
{
_memoryManager.TrackingReprotect(region.Address, region.Size, permission);
}
/// <summary>
/// Returns the number of virtual regions currently being tracked.
/// Useful for tests and metrics.
/// </summary>
/// <returns>The number of virtual regions</returns>
public int GetRegionCount()
{
lock (TrackingLock)
{
return _virtualRegions.Count;
}
}
}
}