Hello,
On Mon, Oct 05, 2015 at 04:23:01PM +0800, Hui Zhu wrote:
> In function obj_malloc:
> if (!class->huge)
> /* record handle in the header of allocated chunk */
> link->handle = handle;
> else
> /* record handle in first_page->private */
> set_page_private(first_page, handle);
> The huge's page save handle to private directly.
>
> But in obj_to_head:
> if (class->huge) {
> VM_BUG_ON(!is_first_page(page));
> return page_private(page);
Typo.
return *(unsigned long*)page_private(page);
Please fix the description.
> } else
> return *(unsigned long *)obj;
> It is used as a pointer.
>
> So change obj_to_head use page_private(page) as value but not pointer
> in obj_to_head.
The reason why there is no problem until now is huge-class page is
born with ZS_FULL so it couldn't be migrated.
Therefore, it shouldn't be real bug in practice.
However, we need this patch for future-work "VM-aware zsmalloced
page migration" to reduce external fragmentation.
>
> Signed-off-by: Hui Zhu <zhuhui@xxxxxxxxxx>
With fixing the comment,
Acked-by: Minchan Kim <minchan@xxxxxxxxxx>
Thanks for the fix, Hui.
--
Kind regards,
Minchan Kim
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