:Allocations of size greater than the radix seem to be returning the
:wrong starting block. Should the allocator return the starting block at
:which it allocated from? If so, sys/kern/subr_alist.c at line 393 should
:be changed to the following (or similar):
:
: mask = (u_daddr_t)-1 >> (ALIST_BMAP_RADIX - n);
: for (j = 0; j < ALIST_META_RADIX; j += n / 2) {
: if ((scan->bm_bitmap & mask) == mask) {
: scan->bm_bitmap &= ~mask;
: return blk; // <== here
: }
: mask <<= n;
: blk += radix * n / 2; // <== here
: }
Yup, you found a bug! I'm going to use a slightly different patch,
instead of iterating the blk in the loop I will just amend the
return(blk + j) I had before to become return(blk + j * radix).
:Also, there appears to be a redundent check for a terminating block at
:line 442: the first check is at the start of the for loop on line 412.
:Removing it shows a 4-5% speed up on allocation from an average of 220ms
: down to an average of 210ms per allocation for sequential single block
:allocations on an Athlon X2 2Ghz.
:
:- Jason
Yah, definitely redundant. The original skeleton was adapted from the
subr_blist code I did years ago and I forgot to remove that bit.
-Matt
Matthew Dillon
<[EMAIL PROTECTED]>
