On Fri, Oct 07, 2022 at 10:07:06AM +0900, Naoya Horiguchi wrote: > From: Naoya Horiguchi <naoya.horiguchi@xxxxxxx> > > Currently PageHWPoison flag does not behave well when experiencing memory > hotremove/hotplug. Any data field in struct page is unreliable when the > associated memory is offlined, and the current mechanism can't tell whether > a memory block is onlined because a new memory devices is installed or > because previous failed offline operations are undone. Especially if > there's a hwpoisoned memory, it's unclear what the best option is. > > So introduce a new mechanism to make struct memory_block remember that > a memory block has hwpoisoned memory inside it. And make any online event > fail if the onlining memory block contains hwpoison. struct memory_block > is freed and reallocated over ACPI-based hotremove/hotplug, but not over > sysfs-based hotremove/hotplug. So the new counter can distinguish these > cases. > > Signed-off-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx> > Reported-by: kernel test robot <lkp@xxxxxxxxx> I glanzed over it and looks good overall. Have a small question though: > @@ -864,6 +878,7 @@ void remove_memory_block_devices(unsigned long start, unsigned long size) > mem = find_memory_block_by_id(block_id); > if (WARN_ON_ONCE(!mem)) > continue; > + num_poisoned_pages_sub(-1UL, memblk_nr_poison(mem)); Why does num_poisoned_pages_sub() have to make this distinction (!-1 == -1) for the hot-remove stage? -- Oscar Salvador SUSE Labs
