On 11/13/2018 05:46 AM, Naoya Horiguchi wrote: > Hi Anshuman, > > On Fri, Nov 09, 2018 at 03:50:41PM +0530, Anshuman Khandual wrote: >> >> 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 ? > There is a race window between page freeing (after successful soft-offline > -> page migration case) and the containment by set_hwpoison_free_buddy_page(). > Or a target page can be allocated just after get_any_page() decided that > the target page is a free page. > So set_hwpoison_free_buddy_page() would safely fail in such cases. Makes sense. Thanks.
