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Misc fixes and optimizations for the granule allocator 

git-svn-id: https://nuttx.svn.sourceforge.net/svnroot/nuttx/trunk@5136 7fd9a85b-ad96-42d3-883c-3090e2eb8679
This commit is contained in:
patacongo 2012-09-12 17:55:03 +00:00
parent 43069a49aa
commit dad6eee444
2 changed files with 146 additions and 40 deletions
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164
nuttx/mm/mm_granalloc.c
View File

@ -67,13 +67,15 @@
*
****************************************************************************/
static inline void gran_mark_allocated(FAR struct gran_s *priv, uintptr_t alloc, unsigned int ngranules)
static inline void gran_mark_allocated(FAR struct gran_s *priv,
uintptr_t alloc,
unsigned int ngranules)
{
unsigned int granno;
unsigned int gatidx;
unsigned int gatbit;
unsigned int avail;
uint32_t mask;
uint32_t gatmask;
/* Determine the granule number of the allocation */
@ -84,28 +86,41 @@ static inline void gran_mark_allocated(FAR struct gran_s *priv, uintptr_t alloc,
gatidx = granno >> 5;
gatbit = granno & 31;
/* Mark bits in the first GAT entry */
/* Mark bits in the GAT entry or entries */
avail = 32 - gatbit;
if (ngranules > avail)
{
priv->gat[gatidx] |= (0xffffffff << gatbit);
/* Mark bits in the first GAT entry */
gatmask =0xffffffff << gatbit;
DEBUGASSERT((priv->gat[gatidx] & gatmask) == 0);
priv->gat[gatidx] |= gatmask;
ngranules -= avail;
/* Mark bits in the second GAT entry */
gatmask = 0xffffffff >> (32 - ngranules);
DEBUGASSERT((priv->gat[gatidx+1] & gatmask) == 0);
priv->gat[gatidx+1] |= gatmask;
}
/* Handle the case where where all of the granules come from one entry */
else
{
mask = 0xffffffff >> (32 - ngranules);
priv->gat[gatidx] |= (mask << gatbit);
/* Mark bits in a single GAT entry */
gatmask = 0xffffffff >> (32 - ngranules);
gatmask <<= gatbit;
DEBUGASSERT((priv->gat[gatidx] & gatmask) == 0);
priv->gat[gatidx] |= gatmask;
return;
}
/* Mark bits in the second GAT entry */
mask = 0xffffffff >> (32 - ngranules);
priv->gat[gatidx+1] |= (mask << gatbit);
}
/****************************************************************************
@ -131,8 +146,10 @@ static inline FAR void *gran_common_alloc(FAR struct gran_s *priv, size_t size)
uint32_t curr;
uint32_t next;
uint32_t mask;
int i;
int j;
int granidx;
int gatidx;
int bitidx;
int shift;
DEBUGASSERT(priv && size <= 32 * (1 << priv->log2gran));
@ -156,12 +173,12 @@ static inline FAR void *gran_common_alloc(FAR struct gran_s *priv, size_t size)
alloc = priv->heapstart;
for (i = 0; i < priv->ngranules; i += 32)
for (granidx = 0; granidx < priv->ngranules; granidx += 32)
{
/* Get the GAT index associated with the granule table entry [i] */
/* Get the GAT index associated with the granule table entry */
j = i >> 5;
curr = priv->gat[j];
gatidx = granidx >> 5;
curr = priv->gat[gatidx];
/* Handle the case where there are no free granules in the entry */
@ -173,25 +190,100 @@ static inline FAR void *gran_common_alloc(FAR struct gran_s *priv, size_t size)
/* Get the next entry from the GAT to support a 64 bit shift */
if (i < priv->ngranules)
if (granidx < priv->ngranules)
{
next = priv->gat[j + 1];
next = priv->gat[gatidx + 1];
}
/* Use all zeroes when are at the last entry in the GAT */
/* Use all ones when are at the last entry in the GAT (meaning
* nothing can be allocated.
*/
else
{
next = 0;
next = 0xffffffff;
}
for (j = 0; j < 32; j++)
/* Search through the allocations in the 'curr' GAT entry
* to see if we can satisfy the allocation starting in that
* entry.
*
* This loop continues until either all of the bits have been
* examined (bitidx >= 32), or until there are insufficient
* granules left to satisfy the allocation.
*/
for (bitidx = 0;
bitidx < 32 && (granidx + bitidx + ngranules) <= priv->ngranules;
)
{
/* Check if we have the allocation at this bit position (0
* means unallocated).
/* Break out if there are no further free bits in 'curr'.
* All of the zero bits might have gotten shifted out.
*/
if ((curr & mask) == 0)
if (curr == 0xffffffff)
{
break;
}
/* Check for the first zero bit in the lower or upper 16-bits.
* From the test above, we know that at least one of the 32-
* bits in 'curr' is zero.
*/
else if ((curr & 0x0000ffff) == 0x0000ffff)
{
/* Not in the lower 16 bits. The first free bit must be
* in the upper 16 bits.
*/
shift = 16;
}
/* We know that the first free bit is now within the lower 16
* bits of 'curr'. Is it in the upper or lower byte?
*/
else if ((curr & 0x0000ff) == 0x000000ff)
{
/* Not in the lower 8 bits. The first free bit must be in
* the upper 8 bits.
*/
shift = 8;
}
/* We know that the first free bit is now within the lower 4
* bits of 'curr'. Is it in the upper or lower nibble?
*/
else if ((curr & 0x00000f) == 0x0000000f)
{
/* Not in the lower 4 bits. The first free bit must be in
* the upper 4 bits.
*/
shift = 4;
}
/* We know that the first free bit is now within the lower 4 bits
* of 'curr'. Is it in the upper or lower pair?
*/
else if ((curr & 0x000003) == 0x00000003)
{
/* Not in the lower 2 bits. The first free bit must be in
* the upper 2 bits.
*/
shift = 2;
}
/* We know that the first free bit is now within the lower 4 bits
* of 'curr'. Check if we have the allocation at this bit position.
*/
else if ((curr & mask) == 0)
{
/* Yes.. mark these granules allocated */
@ -203,20 +295,22 @@ static inline FAR void *gran_common_alloc(FAR struct gran_s *priv, size_t size)
return (FAR void *)alloc;
}
/* The free allocation does not start at this position */
else
{
shift = 1;
}
/* Set up for the next time through the loop. Perform a 64
* bit shift to move to the next gram position.
* bit shift to move to the next gram position andi ncrement
* to the next candidate allocation address.
*/
curr >>= 1;
if ((next & 1) != 0)
{
curr |= 0x80000000;
}
next >>= 1;
/* Increment the next candidate allocation address */
alloc += (1 << priv->log2gran);
alloc += (shift << priv->log2gran);
curr = (curr >> shift) | (next << (32 - shift));
next >>= shift;
bitidx += shift;
}
}
}

22
nuttx/mm/mm_granfree.c
View File

@ -99,26 +99,38 @@ static inline void gran_common_free(FAR struct gran_s *priv,
granmask = (1 << priv->log2gran) - 1;
ngranules = (size + granmask) >> priv->log2gran;
/* Clear bits in the first GAT entry */
/* Clear bits in the GAT entry or entries */
avail = 32 - gatbit;
if (ngranules > avail)
{
priv->gat[gatidx] &= ~(0xffffffff << gatbit);
/* Clear bits in the first GAT entry */
gatmask = (0xffffffff << gatbit);
DEBUGASSERT((priv->gat[gatidx] & gatmask) == gatmask);
priv->gat[gatidx] &= ~gatmask;
ngranules -= avail;
/* Clear bits in the second GAT entry */
gatmask = 0xffffffff >> (32 - ngranules);
priv->gat[gatidx+1] &= ~(gatmask << gatbit);
DEBUGASSERT((priv->gat[gatidx+1] & gatmask) == gatmask);
priv->gat[gatidx+1] &= ~gatmask;
}
/* Handle the case where where all of the granules came from one entry */
else
{
gatmask = 0xffffffff >> (32 - ngranules);
priv->gat[gatidx] &= ~(gatmask << gatbit);
/* Clear bits in a single GAT entry */
gatmask = 0xffffffff >> (32 - ngranules);
gatmask <<= gatbit;
DEBUGASSERT((priv->gat[gatidx] & gatmask) == gatmask);
priv->gat[gatidx] &= ~gatmask;
}
gran_leave_critical(priv);