On Wed, May 11, 2022 at 02:45:30PM -0700, Sultan Alsawaf wrote:
> On Wed, May 11, 2022 at 02:07:19PM -0700, Minchan Kim wrote:
> > Then, how about this?
>
> Your proposal is completely wrong still. My original patch is fine; we can stick
> with that.
>
> > diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
> > index 9152fbde33b5..2f205c18aee4 100644
> > --- a/mm/zsmalloc.c
> > +++ b/mm/zsmalloc.c
> > @@ -1716,12 +1716,31 @@ static enum fullness_group putback_zspage(struct size_class *class,
> > * To prevent zspage destroy during migration, zspage freeing should
> > * hold locks of all pages in the zspage.
> > */
> > -static void lock_zspage(struct zspage *zspage)
> > +static void lock_zspage(struct zs_pool *pool, struct zspage *zspage)
> > {
> > - struct page *page = get_first_page(zspage);
> > -
> > + struct page *page;
> > + int nr_locked;
> > + struct page *locked_pages[ZS_MAX_PAGES_PER_ZSPAGE];
> > + struct address_space *mapping;
> > +retry:
> > + nr_locked = 0;
> > + memset(locked_pages, 0, sizeof(struct page) * ARRAY_SIZE(locked_pages));
>
> This memset() zeroes out memory past the end of the array because it is an array
> of pointers, not an array of page structs; the sizeof() is incorrect.
>
> > + page = get_first_page(zspage);
>
> You can't use get_first_page() outside of the migrate lock.
>
> > do {
> > lock_page(page);
>
> You can't lock a page that you don't own.
That's key point what my idea was wrong.
Thanks for correction!
