Re: Linux 3.19-rc3

Laszlo Ersek
2015-01-10T20:08:56Z

On 01/10/15 20:56, Linus Torvalds wrote:
> On Sat, Jan 10, 2015 at 11:47 AM, Laszlo Ersek <lersek@redhat.com> wrote:
>>
>> I grepped the tree for "fullmm", and only tlb_gather_mmu() seems to set
>> it. There are several instances of that function, but each sets fullmm to:
>>
>> /* Is it from 0 to ~0? */
>> tlb->fullmm = !(start | (end+1));
>>
>> So, a nonzero fullmm seems to imply (end == ~0UL).
>
> Yes. But note how it imples "end == ~0ul", but it does *not* imply
> "tlb->end" having that value.

Ooops! :)

> tlb->end is initialized to zero (not obvious, but it's what the call
> to __tlb_reset_range() does). It's then updated by
> __tlb_adjust_range() as we actually flush individual pages.

Thanks.
Laszlo