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Added documentation on side-effects caused by using MEMF_CLEAR

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obarthel
2022-03-30 09:33:25 +02:00
parent ff5826c54e
commit 4cb621d24d
1 changed files with 16 additions and 2 deletions
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18
library/amiga_pools.c
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@@ -67,7 +67,9 @@ struct MemoryPool
* near the tail of the list.
*/
ULONG mp_MemoryFlags; /* Memory attributes for allocation */
ULONG mp_MemoryFlags; /* Memory attributes for allocation,
* which may also include MEMF_CLEAR.
*/
ULONG mp_PuddleSize; /* Largest allocation which will fit
* into a single puddle.
*/
@@ -282,6 +284,12 @@ static union PuddleUnion * create_new_puddle(struct MemoryPool * mp)
* allocatable memory chunks within the memory header.
*
* Note: no overflow checking is performed!
*
* Also note that the original memory allocation flags are
* being used, which may include MEMF_CLEAR. This means that
* if MEMF_CLEAR is set, the initial allocation will be
* cleared and then the individual puddle allocations made
* through LibAllocPooled() will be cleared, too.
*/
pu = alloc_vec(sizeof(pu->pu_MemHeader) + puddle_size + sizeof(APTR), memory_flags);
if (pu == NULL)
@@ -388,6 +396,12 @@ APTR LibAllocPooled(APTR pool, ULONG mem_size)
* the entire allocated memory which Allocate()
* returned. It's been rounded up to be a
* multiple of MEM_BLOCKSIZE.
*
* Note that the puddle will have been allocated
* with MEMF_CLEAR already, which does not render
* the following memset() call redundant, but
* making the initial puddle allocation use
* MEMF_CLEAR is definitely redundant.
*/
if ((mp->mp_MemoryFlags & MEMF_CLEAR) != 0)
memset(result, 0, (mem_size + MEM_BLOCKMASK) & ~MEM_BLOCKMASK);
@@ -464,7 +478,7 @@ VOID LibFreePooled(APTR pool, APTR memory, ULONG size)
*/
for (pu = (union PuddleUnion *)mp->mp_PuddleMinList.mlh_Head ;
pu->pu_Node.ln_Succ != NULL ;
pu = (union PuddleUnion *)pu->pu_Node.ln_Succ)
pu = (union PuddleUnion *)pu->pu_Node.ln_Succ)
{
/* Did we reach the end of the puddle list? Then
* the given memory address and/or size may be