> >> To generate a diff of this commit:
> >> cvs rdiff -u -r1.42 -r1.42.16.1 src/sys/uvm/uvm_pglist.c
> >
> >> /*
> >> * Test both the ending and starting pages to see if =
> they are
> >> * both free. If the ending and starting pages are =
> same page,
> >> * we only test one of them. If the pages aren't free, =
> there
> >> * is no reason to continue this iteration so advance =
> to the
> >> * next address and try again.
> >> */
> >> if (VM_PAGE_IS_FREE(&pgs[end - 1]) == 0
> >> || end - 1 == tryidx + skip
> >> || VM_PAGE_IS_FREE(&pgs[tryidx + skip]) == 0) {
> >> try += roundup(num, align);
> >> skip = 0;
> >> continue;
> >> }
> >
> > I guess this part can be improved and/or fixed as below.
>
> I initially did something like that but realized it didn't really buy me
> anything since the compiler will actually do something like that
> anyways.
Ah, you're missing my point. Let me rephrase again.
1) If `VM_PAGE_IS_FREE(&pgs[end - 1]) == 0' is false and `end - 1 ==
tryidx + skip' is true, above code skips the region but actually we
found the enough space.
2) If `VM_PAGE_IS_FREE(&pgs[end - 1]) == 0' is false and `end - 1 ==
tryidx + skip' is false but `VM_PAGE_IS_FREE(&pgs[tryidx + skip])
== 0' is true, it is better to advance the `try' by roundup(skip +
1, align) instead of roundup(num, align).
enami.
