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[POWERPC] rheap - eliminates internal fragments caused by alignment 

The patch adds fragments caused by rh_alloc_align() back to free list, instead
of allocating the whole chunk of memory.  This will greatly improve memory
utilization managed by rheap.

It solves MURAM not enough problem with 3 UCCs enabled on MPC8323.

Signed-off-by: Li Yang <leoli@freescale.com>
Acked-by: Joakim Tjernlund <joakim.tjernlund@transmode.se> 
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
This commit is contained in:
Li Yang 2007-06-18 19:29:21 +08:00 committed by Kumar Gala
parent 7b7a57c77d
commit 7c8545e984
1 changed files with 29 additions and 19 deletions
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48
arch/powerpc/lib/rheap.c
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@ -437,27 +437,26 @@ unsigned long rh_alloc_align(rh_info_t * info, int size, int alignment, const ch
struct list_head *l;
rh_block_t *blk;
rh_block_t *newblk;
unsigned long start;
unsigned long start, sp_size;
/* Validate size, and alignment must be power of two */
if (size <= 0 || (alignment & (alignment - 1)) != 0)
return (unsigned long) -EINVAL;
/* given alignment larger that default rheap alignment */
if (alignment > info->alignment)
size += alignment - 1;
/* Align to configured alignment */
size = (size + (info->alignment - 1)) & ~(info->alignment - 1);
if (assure_empty(info, 1) < 0)
if (assure_empty(info, 2) < 0)
return (unsigned long) -ENOMEM;
blk = NULL;
list_for_each(l, &info->free_list) {
blk = list_entry(l, rh_block_t, list);
if (size <= blk->size)
break;
if (size <= blk->size) {
start = (blk->start + alignment - 1) & ~(alignment - 1);
if (start + size <= blk->start + blk->size)
break;
}
blk = NULL;
}
@ -470,25 +469,36 @@ unsigned long rh_alloc_align(rh_info_t * info, int size, int alignment, const ch
list_del(&blk->list);
newblk = blk;
} else {
/* Fragment caused, split if needed */
/* Create block for fragment in the beginning */
sp_size = start - blk->start;
if (sp_size) {
rh_block_t *spblk;
spblk = get_slot(info);
spblk->start = blk->start;
spblk->size = sp_size;
/* add before the blk */
list_add(&spblk->list, blk->list.prev);
}
newblk = get_slot(info);
newblk->start = blk->start;
newblk->start = start;
newblk->size = size;
/* blk still in free list, with updated start, size */
blk->start += size;
blk->size -= size;
/* blk still in free list, with updated start and size
* for fragment in the end */
blk->start = start + size;
blk->size -= sp_size + size;
/* No fragment in the end, remove blk */
if (blk->size == 0) {
list_del(&blk->list);
release_slot(info, blk);
}
}
newblk->owner = owner;
start = newblk->start;
attach_taken_block(info, newblk);
/* for larger alignment return fixed up pointer */
/* this is no problem with the deallocator since */
/* we scan for pointers that lie in the blocks */
if (alignment > info->alignment)
start = (start + alignment - 1) & ~(alignment - 1);
return start;
}