On Tue, Nov 17, 2009 at 04:17:07PM +0900, KOSAKI Motohiro wrote: > Non MM subsystem must not use PF_MEMALLOC. Memory reclaim need few > memory, anyone must not prevent it. Otherwise the system cause > mysterious hang-up and/or OOM Killer invokation. This code is also on the critical path, for example, if you are swapping onto a dm device. (There are ways we could reduce its use further as not every dm ioctl needs to be on the critical path and the buffer size could be limited for the ioctls that do.) But what situations have been causing you trouble? The OOM killer must generally avoid killing userspace processes that suspend & resume dm devices, and there are tight restrictions on what those processes can do safely between suspending and resuming. Alasdair -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel