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Change implementation so that variable sized slabs are used to allow arbitrary sized array allocations

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7663 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Sumant Kowshik 2003-08-07 05:31:04 +00:00
parent 8e37bd0330
commit d105a8707a
1 changed files with 197 additions and 71 deletions

268
runtime/GCCLibraries/libpoolalloc/PoolAllocatorChained.c

@ -1,11 +1,17 @@
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#undef assert
#define assert(X)
#define NODES_PER_SLAB 65536
/* In the current implementation, each slab in the pool has NODES_PER_SLAB
* nodes unless the isSingleArray flag is set in which case it contains a
* single array of size ArraySize. Small arrays (size <= NODES_PER_SLAB) are
* still allocated in the slabs of size NODES_PER_SLAB
*/
#define NODES_PER_SLAB 512
typedef struct PoolTy {
void *Data;
@ -24,6 +30,11 @@ typedef struct PoolSlab {
struct PoolSlab *Next;
unsigned char AllocatedBitVector[NODES_PER_SLAB/8];
unsigned char StartOfAllocation[NODES_PER_SLAB/8];
unsigned isSingleArray; /* If this slab is used for exactly one array */
/* The array is allocated from the start to the end of the slab */
unsigned ArraySize; /* The size of the array allocated */
char Data[1]; /* Buffer to hold data in this slab... variable sized */
} PoolSlab;
@ -45,7 +56,10 @@ typedef struct PoolSlab {
/* poolinit - Initialize a pool descriptor to empty
*/
void poolinit(PoolTy *Pool, unsigned NodeSize) {
assert(Pool && "Null pool pointer passed into poolinit!");
if (!Pool) {
printf("Null pool pointer passed into poolinit!\n");
exit(1);
}
Pool->NodeSize = NodeSize;
Pool->Data = 0;
@ -55,7 +69,11 @@ void poolinit(PoolTy *Pool, unsigned NodeSize) {
}
void poolmakeunfreeable(PoolTy *Pool) {
assert(Pool && "Null pool pointer passed in to poolmakeunfreeable!");
if (!Pool) {
printf("Null pool pointer passed in to poolmakeunfreeable!\n");
exit(1);
}
Pool->FreeablePool = 0;
}
@ -63,7 +81,11 @@ void poolmakeunfreeable(PoolTy *Pool) {
*/
void pooldestroy(PoolTy *Pool) {
PoolSlab *PS;
assert(Pool && "Null pool pointer passed in to pooldestroy!");
if (!Pool) {
printf("Null pool pointer passed in to pooldestroy!\n");
exit(1);
}
PS = (PoolSlab*)Pool->Data;
while (PS) {
PoolSlab *Next = PS->Next;
@ -75,6 +97,12 @@ void pooldestroy(PoolTy *Pool) {
static void *FindSlabEntry(PoolSlab *PS, unsigned NodeSize) {
/* Loop through all of the slabs looking for one with an opening */
for (; PS; PS = PS->Next) {
/* If the slab is a single array, go on to the next slab */
/* Don't allocate single nodes in a SingleArray slab */
if (PS->isSingleArray)
continue;
/* Check to see if there are empty entries at the end of the slab... */
if (PS->LastUsed < NODES_PER_SLAB-1) {
/* Mark the returned entry used */
@ -118,8 +146,16 @@ char *poolalloc(PoolTy *Pool) {
PoolSlab *PS;
void *Result;
assert(Pool && "Null pool pointer passed in to poolalloc!");
if (!Pool) {
printf("Null pool pointer passed in to poolalloc!\n");
exit(1);
}
NodeSize = Pool->NodeSize;
// Return if this pool has size 0
if (NodeSize == 0)
return 0;
PS = (PoolSlab*)Pool->Data;
if ((Result = FindSlabEntry(PS, NodeSize)))
@ -128,11 +164,17 @@ char *poolalloc(PoolTy *Pool) {
/* Otherwise we must allocate a new slab and add it to the list */
PS = (PoolSlab*)malloc(sizeof(PoolSlab)+NodeSize*NODES_PER_SLAB-1);
assert (PS && "Could not allocate memory!");
if (!PS) {
printf("poolalloc: Could not allocate memory!");
exit(1);
}
/* Initialize the slab to indicate that the first element is allocated */
PS->FirstUnused = 1;
PS->LastUsed = 0;
/* This is not a single array */
PS->isSingleArray = 0;
PS->ArraySize = 0;
MARK_NODE_ALLOCATED(PS, 0);
SET_START_BIT(PS, 0);
@ -149,56 +191,97 @@ void poolfree(PoolTy *Pool, char *Node) {
PoolSlab **PPS;
unsigned idxiter;
assert(Pool && "Null pool pointer passed in to poolfree!");
if (!Pool) {
printf("Null pool pointer passed in to poolfree!\n");
exit(1);
}
NodeSize = Pool->NodeSize;
// Return if this pool has size 0
if (NodeSize == 0)
return;
PS = (PoolSlab*)Pool->Data;
PPS = (PoolSlab**)&Pool->Data;
/* Seach for the slab that contains this node... */
while (&PS->Data[0] > Node || &PS->Data[NodeSize*NODES_PER_SLAB] < Node) {
assert(PS && "free'd node not found in allocation pool specified!");
/* Search for the slab that contains this node... */
while (&PS->Data[0] > Node || &PS->Data[NodeSize*NODES_PER_SLAB-1] < Node) {
if (!PS) {
printf("poolfree: node being free'd not found in allocation pool specified!\n");
exit(1);
}
PPS = &PS->Next;
PS = PS->Next;
}
/* PS now points to the slab where Node is */
Idx = (Node-&PS->Data[0])/NodeSize;
assert(Idx < NODES_PER_SLAB && "Pool slab searching loop broken!");
assert(ALLOCATION_BEGINS(PS, Idx) &&
"Attempt to free middle of allocated array");
if (PS->isSingleArray) {
/* Free the first node */
CLEAR_START_BIT(PS, Idx);
MARK_NODE_FREE(PS, Idx);
/* If this slab is a SingleArray */
// Free all nodes
idxiter = Idx + 1;
while (idxiter < NODES_PER_SLAB && (!ALLOCATION_BEGINS(PS,idxiter)) &&
(NODE_ALLOCATED(PS, idxiter))) {
MARK_NODE_FREE(PS, idxiter);
}
if (Idx != 0) {
printf("poolfree: Attempt to free middle of allocated array\n");
exit(1);
}
if (!NODE_ALLOCATED(PS,0)) {
printf("poolfree: Attempt to free node that is already freed\n");
exit(1);
}
/* Mark this SingleArray slab as being free by just marking the first
entry as free*/
MARK_NODE_FREE(PS, 0);
} else {
/* If this slab is not a SingleArray */
if (!ALLOCATION_BEGINS(PS, Idx)) {
printf("poolfree: Attempt to free middle of allocated array\n");
}
/* Update the first free field if this node is below the free node line */
if (Idx < PS->FirstUnused) PS->FirstUnused = Idx;
/* If we are not freeing the last element in a slab... */
if (idxiter - 1 != PS->LastUsed) {
return;
}
/* Free the first node */
if (!NODE_ALLOCATED(PS, Idx)) {
printf("poolfree: Attempt to free node that is already freed\n");
exit(1);
}
CLEAR_START_BIT(PS, Idx);
MARK_NODE_FREE(PS, Idx);
// Free all nodes
idxiter = Idx + 1;
while (idxiter < NODES_PER_SLAB && (!ALLOCATION_BEGINS(PS,idxiter)) &&
(NODE_ALLOCATED(PS, idxiter))) {
MARK_NODE_FREE(PS, idxiter);
++idxiter;
}
/* Otherwise we are freeing the last element in a slab... shrink the
* LastUsed marker down to last used node.
*/
PS->LastUsed = Idx;
do {
--PS->LastUsed;
/* Fixme, this should scan the allocated array an entire byte at a time for
* performance!
/* Update the first free field if this node is below the free node line */
if (Idx < PS->FirstUnused) PS->FirstUnused = Idx;
/* If we are not freeing the last element in a slab... */
if (idxiter - 1 != PS->LastUsed) {
return;
}
/* Otherwise we are freeing the last element in a slab... shrink the
* LastUsed marker down to last used node.
*/
} while (PS->LastUsed >= 0 && (!NODE_ALLOCATED(PS, PS->LastUsed)));
assert(PS->FirstUnused <= PS->LastUsed+1 &&
"FirstUnused field was out of date!");
PS->LastUsed = Idx;
do {
--PS->LastUsed;
/* Fixme, this should scan the allocated array an entire byte at a time
* for performance!
*/
} while (PS->LastUsed >= 0 && (!NODE_ALLOCATED(PS, PS->LastUsed)));
assert(PS->FirstUnused <= PS->LastUsed+1 &&
"FirstUnused field was out of date!");
}
/* Ok, if this slab is empty, we unlink it from the of slabs and either move
* it to the head of the list, or free it, depending on whether or not there
@ -206,33 +289,38 @@ void poolfree(PoolTy *Pool, char *Node) {
*/
/* Do this only if the pool is freeable */
if (Pool->FreeablePool) {
if (PS->LastUsed == -1) { /* Empty slab? */
if (PS->isSingleArray) {
/* If it is a SingleArray, just free it */
*PPS = PS->Next;
free(PS);
} else if (PS->LastUsed == -1) { /* Empty slab? */
PoolSlab *HeadSlab;
*PPS = PS->Next; /* Unlink from the list of slabs... */
HeadSlab = (PoolSlab*)Pool->Data;
if (HeadSlab && HeadSlab->LastUsed == -1){/* List already has empty slab? */
free(PS); /* Free memory for slab */
if (HeadSlab && HeadSlab->LastUsed == -1){/*List already has empty slab?*/
free(PS); /*Free memory for slab */
} else {
PS->Next = HeadSlab; /* No empty slab yet, add this */
Pool->Data = PS; /* one to the head of the list */
PS->Next = HeadSlab; /*No empty slab yet, add this*/
Pool->Data = PS; /*one to the head of the list */
}
}
} else {
/* Pool is not freeable for safety reasons */
/* Leave it in the list of PoolSlabs as an empty PoolSlab */
if (PS->LastUsed == -1) {
PS->FirstUnused = 0;
/* Do not free the pool, but move it to the head of the list if there is no
empty slab there already */
PoolSlab *HeadSlab;
HeadSlab = (PoolSlab*)Pool->Data;
if (HeadSlab && HeadSlab->LastUsed != -1) {
PS->Next = HeadSlab;
Pool->Data = PS;
if (!PS->isSingleArray)
if (PS->LastUsed == -1) {
PS->FirstUnused = 0;
/* Do not free the pool, but move it to the head of the list if there is
no empty slab there already */
PoolSlab *HeadSlab;
HeadSlab = (PoolSlab*)Pool->Data;
if (HeadSlab && HeadSlab->LastUsed != -1) {
PS->Next = HeadSlab;
Pool->Data = PS;
}
}
}
}
}
@ -243,6 +331,21 @@ static void *FindSlabEntryArray(PoolSlab *PS, unsigned NodeSize,
/* Loop through all of the slabs looking for one with an opening */
for (; PS; PS = PS->Next) {
/* For large array allocation */
if (Size > NODES_PER_SLAB) {
/* If this slab is a SingleArray that is free with size > Size, use it */
if (PS->isSingleArray && !NODE_ALLOCATED(PS,0) && PS->ArraySize >= Size) {
/* Allocate the array in this slab */
MARK_NODE_ALLOCATED(PS,0); /* In a single array, only the first node
needs to be marked */
return &PS->Data[0];
} else
continue;
} else if (PS->isSingleArray)
continue; /* Do not allocate small arrays in SingleArray slabs */
/* For small array allocation */
/* Check to see if there are empty entries at the end of the slab... */
if (PS->LastUsed < NODES_PER_SLAB-Size) {
/* Mark the returned entry used and set the start bit*/
@ -277,7 +380,7 @@ static void *FindSlabEntryArray(PoolSlab *PS, unsigned NodeSize,
foundArray = 0;
if (foundArray) {
/* Successfully allocate out the first unused node */
/* Successfully allocate starting from the first unused node */
SET_START_BIT(PS, Idx);
for (i = Idx; i < Idx + Size; ++i)
MARK_NODE_ALLOCATED(PS, i);
@ -303,28 +406,51 @@ char* poolallocarray(PoolTy* Pool, unsigned Size) {
void *Result;
unsigned i;
assert(Pool && "Null pool pointer passed in to poolallocarray!");
NodeSize = Pool->NodeSize;
PS = (PoolSlab*)Pool->Data;
if (!Pool) {
printf("Null pool pointer passed to poolallocarray!\n");
exit(1);
}
assert(Size <= NODES_PER_SLAB &&
"Exceeded the maximum size of an individual malloc");
NodeSize = Pool->NodeSize;
// Return if this pool has size 0
if (NodeSize == 0)
return 0;
PS = (PoolSlab*)Pool->Data;
if ((Result = FindSlabEntryArray(PS, NodeSize,Size)))
return Result;
/* Otherwise we must allocate a new slab and add it to the list */
PS = (PoolSlab*)malloc(sizeof(PoolSlab)+NodeSize*NODES_PER_SLAB-1);
if (Size > NODES_PER_SLAB) {
/* Allocate a new slab of size Size */
PS = (PoolSlab*)malloc(sizeof(PoolSlab)+NodeSize*Size-1);
if (!PS) {
printf("poolallocarray: Could not allocate memory!\n");
exit(1);
}
PS->isSingleArray = 1;
PS->ArraySize = Size;
MARK_NODE_ALLOCATED(PS, 0);
} else {
PS = (PoolSlab*)malloc(sizeof(PoolSlab)+NodeSize*NODES_PER_SLAB-1);
if (!PS) {
printf("poolallocarray: Could not allocate memory!\n");
exit(1);
}
assert (PS && "Could not allocate memory!");
/* Initialize the slab to indicate that the first element is allocated */
PS->FirstUnused = Size;
PS->LastUsed = Size - 1;
PS->isSingleArray = 0;
PS->ArraySize = 0;
/* Initialize the slab to indicate that the first element is allocated */
PS->FirstUnused = Size;
PS->LastUsed = Size - 1;
SET_START_BIT(PS, 0);
for (i = 0; i < Size; ++i) {
MARK_NODE_ALLOCATED(PS, i);
SET_START_BIT(PS, 0);
for (i = 0; i < Size; ++i) {
MARK_NODE_ALLOCATED(PS, i);
}
}
/* Add the slab to the list... */