On Tue, 2014-06-24 at 09:31 +0900, Yasuaki Ishimatsu wrote:
> (2014/06/21 3:30), Toshi Kani wrote:
> > On Wed, 2014-06-18 at 15:38 +0900, Yasuaki Ishimatsu wrote:
> > :
> >> @@ -186,7 +186,12 @@ void sync_global_pgds(unsigned long start, unsigned long end)
> >> const pgd_t *pgd_ref = pgd_offset_k(address);
> >> struct page *page;
> >>
> >> - if (pgd_none(*pgd_ref))
> >> + /*
> >> + * When it is called after memory hot remove, pgd_none()
> >> + * returns true. In this case (removed == 1), we must clear
> >> + * the PGD entries in the local PGD level page.
> >> + */
> >> + if (pgd_none(*pgd_ref) && !removed)
> >> continue;
> >>
> >> spin_lock(&pgd_lock);
> >> @@ -199,12 +204,18 @@ void sync_global_pgds(unsigned long start, unsigned long end)
> >> pgt_lock = &pgd_page_get_mm(page)->page_table_lock;
> >> spin_lock(pgt_lock);
> >>
> >> - if (pgd_none(*pgd))
> >> - set_pgd(pgd, *pgd_ref);
> >> - else
>
> >> + if (!pgd_none(*pgd_ref) && !pgd_none(*pgd))
> >> BUG_ON(pgd_page_vaddr(*pgd)
> >> != pgd_page_vaddr(*pgd_ref));
> >>
> >> + if (removed) {
> >
> > Shouldn't this condition be "else if"?
>
> The first if sentence checks whether PGDs hit to BUG_ON. And the second
> if sentence checks whether the function was called after hot-removing memory.
> I think that the first if sentence and the second if sentence check different
> things. So I think the condition should be "if" sentence.
When the 1st if sentence is true, you have no additional operation and
the 2nd if sentence is redundant. But I agree that the two ifs can be
logically separated. So:
Acked-by: Toshi Kani <toshi.kani@xxxxxx>
Thanks,
-Toshi
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