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dll: dirbuf:

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- FspFileSystemAcquireDirectoryBufferEx takes hint for initial capacity.
- Buffer allocation strategy has been improved to minimize reallocation.
- Quick sort of directory entries now implements median of three partitioning. This improves performance of sorting already sorted data.
This commit is contained in:
Bill Zissimopoulos
2022-03-22 16:47:40 +00:00
parent 868812d248
commit 7527155cb8
4 changed files with 102 additions and 20 deletions
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38
src/dll/dirbuf.c
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@ -21,6 +21,11 @@
#include <dll/library.h>
#define FspFileSystemDirectoryBufferLoBound (256)
#define FspFileSystemDirectoryBufferHiBound (1024 * 1024)
#define FspFileSystemDirectoryBufferLoFactor (4)
#define FspFileSystemDirectoryBufferHiFactor (2)
#define RETURN(R, B) \
do \
{ \
@ -32,7 +37,7 @@
typedef struct
{
SRWLOCK Lock;
ULONG Capacity, LoMark, HiMark;
ULONG InitialCapacity, Capacity, LoMark, HiMark;
PUINT8 Buffer;
} FSP_FILE_SYSTEM_DIRECTORY_BUFFER;
@ -179,12 +184,15 @@ static VOID FspFileSystemQSortDirectoryBuffer(PUINT8 Buffer, PULONG Index, int l
{
while (r > l)
{
#if 0
#if 1
exch(Index[(l + r) / 2], Index[r - 1]);
compexch(Index[l], Index[r - 1]);
compexch(Index[l], Index[r]);
compexch(Index[r - 1], Index[r]);
if (r - 1 <= l + 1)
break;
i = FspFileSystemPartitionDirectoryBuffer(Buffer, Index, l + 1, r - 1);
#else
i = FspFileSystemPartitionDirectoryBuffer(Buffer, Index, l, r);
@ -224,8 +232,8 @@ static inline VOID FspFileSystemSortDirectoryBuffer(FSP_FILE_SYSTEM_DIRECTORY_BU
FspFileSystemQSortDirectoryBuffer(Buffer, Index, 0, Count - 1);
}
FSP_API BOOLEAN FspFileSystemAcquireDirectoryBuffer(PVOID *PDirBuffer,
BOOLEAN Reset, PNTSTATUS PResult)
FSP_API BOOLEAN FspFileSystemAcquireDirectoryBufferEx(PVOID* PDirBuffer,
BOOLEAN Reset, ULONG CapacityHint, PNTSTATUS PResult)
{
FSP_FILE_SYSTEM_DIRECTORY_BUFFER *DirBuffer = FspInterlockedLoadPointer(PDirBuffer);
@ -234,10 +242,20 @@ FSP_API BOOLEAN FspFileSystemAcquireDirectoryBuffer(PVOID *PDirBuffer,
static SRWLOCK CreateLock = SRWLOCK_INIT;
FSP_FILE_SYSTEM_DIRECTORY_BUFFER *NewDirBuffer;
/* compute next (or equal) power of 2; ensure fits within bounds */
ULONG bitidx;
if (_BitScanReverse(&bitidx, CapacityHint - 1))
CapacityHint = (1 << (1 + bitidx));
CapacityHint = FspFileSystemDirectoryBufferLoBound > CapacityHint ?
FspFileSystemDirectoryBufferLoBound : CapacityHint;
CapacityHint = FspFileSystemDirectoryBufferHiBound < CapacityHint ?
FspFileSystemDirectoryBufferHiBound : CapacityHint;
NewDirBuffer = MemAlloc(sizeof *NewDirBuffer);
if (0 == NewDirBuffer)
RETURN(STATUS_INSUFFICIENT_RESOURCES, FALSE);
memset(NewDirBuffer, 0, sizeof *NewDirBuffer);
NewDirBuffer->InitialCapacity = CapacityHint;
InitializeSRWLock(&NewDirBuffer->Lock);
AcquireSRWLockExclusive(&NewDirBuffer->Lock);
@ -267,6 +285,12 @@ FSP_API BOOLEAN FspFileSystemAcquireDirectoryBuffer(PVOID *PDirBuffer,
RETURN(STATUS_SUCCESS, FALSE);
}
FSP_API BOOLEAN FspFileSystemAcquireDirectoryBuffer(PVOID *PDirBuffer,
BOOLEAN Reset, PNTSTATUS PResult)
{
return FspFileSystemAcquireDirectoryBufferEx(PDirBuffer, Reset, 0, PResult);
}
FSP_API BOOLEAN FspFileSystemFillDirectoryBuffer(PVOID *PDirBuffer,
FSP_FSCTL_DIR_INFO *DirInfo, PNTSTATUS PResult)
{
@ -301,7 +325,7 @@ FSP_API BOOLEAN FspFileSystemFillDirectoryBuffer(PVOID *PDirBuffer,
if (0 == Buffer)
{
Buffer = MemAlloc(Capacity = 512);
Buffer = MemAlloc(Capacity = DirBuffer->InitialCapacity);
if (0 == Buffer)
RETURN(STATUS_INSUFFICIENT_RESOURCES, FALSE);
@ -309,7 +333,9 @@ FSP_API BOOLEAN FspFileSystemFillDirectoryBuffer(PVOID *PDirBuffer,
}
else
{
Buffer = MemRealloc(Buffer, Capacity = DirBuffer->Capacity * 2);
ULONG Factor = FspFileSystemDirectoryBufferHiBound > DirBuffer->Capacity ?
FspFileSystemDirectoryBufferLoFactor : FspFileSystemDirectoryBufferHiFactor;
Buffer = MemRealloc(Buffer, Capacity = DirBuffer->Capacity * Factor);
if (0 == Buffer)
RETURN(STATUS_INSUFFICIENT_RESOURCES, FALSE);