Constant syscall::flag::PARTIAL_ALLOC

pub const PARTIAL_ALLOC: PhysallocFlags;

Do a “partial allocation”, which means that not all of the frames specified in the frame count size actually have to be allocated. This means that if the allocator was unable to find a physical memory range large enough, it can instead return whatever range it decides is optimal. Thus, instead of letting one driver get an expensive 128MiB physical memory range when the physical memory has become fragmented, and failing, it can instead be given a more optimal range. If the device supports scatter-gather lists, then the driver only has to allocate more ranges, and the device will do vectored I/O.

PARTIAL_ALLOC supports different allocation strategies, refer to Optimal, GreatestRange.