Matthew Dillon wrote:
dillon 2007/04/09 10:10:00 PDT
DragonFly src repository
Modified files:
sys/conf files
Added files:
sys/sys alist.h
sys/kern subr_alist.c
Log:
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
}
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
