5 Jun
2010
5 Jun
'10
5:53 p.m.
Author: sir_richard
Date: Sat Jun 5 19:53:17 2010
New Revision: 47594
URL: http://svn.reactos.org/svn/reactos?rev=47594&view=rev
Log:
[NTOS]: Use logical math operations on the various
block<->entry<->free_list_head operations in the pool code, instead of
works-by-chance-and-assumption pointer math operations. This will now allow pool
implementations where the pool header is not the size of a pool block (and the size of a
LIST_ENTRY, by definition, although, even that, could change, if we choose to implement a
cache-aligned overhead).
Modified:
trunk/reactos/ntoskrnl/mm/ARM3/expool.c
Modified: trunk/reactos/ntoskrnl/mm/ARM3/expool.c
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/mm/ARM3/expool.c?…
==============================================================================
--- trunk/reactos/ntoskrnl/mm/ARM3/expool.c [iso-8859-1] (original)
+++ trunk/reactos/ntoskrnl/mm/ARM3/expool.c [iso-8859-1] Sat Jun 5 19:53:17 2010
@@ -28,6 +28,13 @@
PVOID PoolTrackTable;
PKGUARDED_MUTEX ExpPagedPoolMutex;
+/* Pool block/header/list access macros */
+#define POOL_ENTRY(x) (PPOOL_HEADER)((ULONG_PTR)x - sizeof(POOL_HEADER))
+#define POOL_FREE_BLOCK(x) (PLIST_ENTRY)((ULONG_PTR)x + sizeof(POOL_HEADER))
+#define POOL_BLOCK(x, i) (PPOOL_HEADER)((ULONG_PTR)x + ((i) * POOL_BLOCK_SIZE))
+#define POOL_NEXT_BLOCK(x) POOL_BLOCK(x, x->BlockSize)
+#define POOL_PREV_BLOCK(x) POOL_BLOCK(x, -x->PreviousSize)
+
/* PRIVATE FUNCTIONS **********************************************************/
VOID
@@ -68,7 +75,11 @@
//
NextEntry = PoolDescriptor->ListHeads;
LastEntry = NextEntry + POOL_LISTS_PER_PAGE;
- while (NextEntry < LastEntry) InitializeListHead(NextEntry++);
+ while (NextEntry < LastEntry)
+ {
+ InitializeListHead(NextEntry);
+ NextEntry++;
+ }
}
VOID
@@ -239,8 +250,7 @@
// request would've been treated as a POOL_MAX_ALLOC earlier and resulted in
// the direct allocation of pages.
//
- i = (NumberOfBytes + sizeof(POOL_HEADER) + sizeof(LIST_ENTRY) - 1) /
- sizeof(POOL_HEADER);
+ i = (NumberOfBytes + sizeof(POOL_HEADER) + (POOL_BLOCK_SIZE - 1)) / POOL_BLOCK_SIZE;
//
// Loop in the free lists looking for a block if this size. Start with the
@@ -281,7 +291,7 @@
// there is a guarantee that any block on this list will either be
// of the correct size, or perhaps larger.
//
- Entry = (PPOOL_HEADER)RemoveHeadList(ListHead) - 1;
+ Entry = POOL_ENTRY(RemoveHeadList(ListHead));
ASSERT(Entry->BlockSize >= i);
ASSERT(Entry->PoolType == 0);
@@ -302,7 +312,7 @@
// turn it into a fragment that contains the leftover data
// that we don't need to satisfy the caller's request
//
- FragmentEntry = Entry + i;
+ FragmentEntry = POOL_BLOCK(Entry, i);
FragmentEntry->BlockSize = Entry->BlockSize - i;
//
@@ -314,7 +324,7 @@
// Now get the block that follows the new fragment and check
// if it's still on the same page as us (and not at the end)
//
- NextEntry = FragmentEntry + FragmentEntry->BlockSize;
+ NextEntry = POOL_NEXT_BLOCK(FragmentEntry);
if (PAGE_ALIGN(NextEntry) != NextEntry)
{
//
@@ -346,14 +356,14 @@
// This is the entry that will actually end up holding the
// allocation!
//
- Entry += Entry->BlockSize;
+ Entry = POOL_NEXT_BLOCK(Entry);
Entry->PreviousSize = FragmentEntry->BlockSize;
//
// And now let's go to the entry after that one and check if
// it's still on the same page, and not at the end
//
- NextEntry = Entry + i;
+ NextEntry = POOL_BLOCK(Entry, i);
if (PAGE_ALIGN(NextEntry) != NextEntry)
{
//
@@ -387,7 +397,7 @@
// Insert the free entry into the free list for this size
//
InsertTailList(&PoolDesc->ListHeads[BlockSize - 1],
- (PLIST_ENTRY)FragmentEntry + 1);
+ POOL_FREE_BLOCK(FragmentEntry));
}
}
@@ -402,7 +412,9 @@
// Return the pool allocation
//
Entry->PoolTag = Tag;
- return ++Entry;
+ (POOL_FREE_BLOCK(Entry))->Flink = NULL;
+ (POOL_FREE_BLOCK(Entry))->Blink = NULL;
+ return POOL_FREE_BLOCK(Entry);
}
} while (++ListHead != &PoolDesc->ListHeads[POOL_LISTS_PER_PAGE]);
@@ -410,6 +422,7 @@
// There were no free entries left, so we have to allocate a new fresh page
//
Entry = MiAllocatePoolPages(PoolType, PAGE_SIZE);
+ ASSERT(Entry != NULL);
Entry->Ulong1 = 0;
Entry->BlockSize = i;
Entry->PoolType = PoolType + 1;
@@ -420,8 +433,8 @@
// to create now. The free bytes are the whole page minus what was allocated
// and then converted into units of block headers.
//
- BlockSize = (PAGE_SIZE / sizeof(POOL_HEADER)) - i;
- FragmentEntry = Entry + i;
+ BlockSize = (PAGE_SIZE / POOL_BLOCK_SIZE) - i;
+ FragmentEntry = POOL_BLOCK(Entry, i);
FragmentEntry->Ulong1 = 0;
FragmentEntry->BlockSize = BlockSize;
FragmentEntry->PreviousSize = i;
@@ -442,8 +455,8 @@
// And insert the free entry into the free list for this block size
//
InsertTailList(&PoolDesc->ListHeads[BlockSize - 1],
- (PLIST_ENTRY)FragmentEntry + 1);
-
+ POOL_FREE_BLOCK(FragmentEntry));
+
//
// Release the pool lock
//
@@ -454,7 +467,7 @@
// And return the pool allocation
//
Entry->PoolTag = Tag;
- return ++Entry;
+ return POOL_FREE_BLOCK(Entry);
}
/*
@@ -485,7 +498,7 @@
POOL_TYPE PoolType;
PPOOL_DESCRIPTOR PoolDesc;
BOOLEAN Combined = FALSE;
-
+#if 1
//
// Check for paged pool
//
@@ -498,6 +511,7 @@
ExFreePagedPool(P);
return;
}
+#endif
//
// Quickly deal with big page allocations
@@ -526,7 +540,7 @@
//
// Get the pointer to the next entry
//
- NextEntry = Entry + BlockSize;
+ NextEntry = POOL_BLOCK(Entry, BlockSize);
//
// Acquire the pool lock
@@ -559,7 +573,7 @@
// The block is at least big enough to have a linked list, so go
// ahead and remove it
//
- RemoveEntryList((PLIST_ENTRY)NextEntry + 1);
+ RemoveEntryList(POOL_FREE_BLOCK(NextEntry));
}
//
@@ -577,7 +591,7 @@
//
// Great, grab that entry and check if it's free
//
- NextEntry = Entry - Entry->PreviousSize;
+ NextEntry = POOL_PREV_BLOCK(Entry);
if (NextEntry->PoolType == 0)
{
//
@@ -596,7 +610,7 @@
// The block is at least big enough to have a linked list, so go
// ahead and remove it
//
- RemoveEntryList((PLIST_ENTRY)NextEntry + 1);
+ RemoveEntryList(POOL_FREE_BLOCK(NextEntry));
}
//
@@ -618,7 +632,7 @@
// page, they could've all been combined).
//
if ((PAGE_ALIGN(Entry) == Entry) &&
- (PAGE_ALIGN(Entry + Entry->BlockSize) == Entry + Entry->BlockSize))
+ (PAGE_ALIGN(POOL_NEXT_BLOCK(Entry)) == POOL_NEXT_BLOCK(Entry)))
{
//
// In this case, release the pool lock, and free the page
@@ -644,7 +658,7 @@
// Get the first combined block (either our original to begin with, or
// the one after the original, depending if we combined with the previous)
//
- NextEntry = Entry + BlockSize;
+ NextEntry = POOL_NEXT_BLOCK(Entry);
//
// As long as the next block isn't on a page boundary, have it point
@@ -656,7 +670,7 @@
//
// Insert this new free block, and release the pool lock
//
- InsertHeadList(&PoolDesc->ListHeads[BlockSize - 1], (PLIST_ENTRY)Entry + 1);
+ InsertHeadList(&PoolDesc->ListHeads[BlockSize - 1], POOL_FREE_BLOCK(Entry));
ExUnlockPool(PoolDesc, OldIrql);
}