On 11/09/2018 12:17 PM, Naoya Horiguchi wrote: > set_hwpoison_free_buddy_page() could fail, then the target page is > finally not isolated, so it's better to report -EBUSY for userspace > to know the failure and chance of retry. > IIUC set_hwpoison_free_buddy_page() could only fail if the page is not free in the buddy. At least for soft_offline_huge_page() that wont be the case otherwise dissolve_free_huge_page() would have returned non zero -EBUSY. Is there any other reason set_hwpoison_free_buddy_page() would not succeed ? > And for consistency, this patch moves set_hwpoison_free_buddy_page() > in unmap_and_move() to __soft_offline_page(). Yeah this check should be handled in soft offline functions not inside migrations they trigger.