> If memory has been depleted in lowmem zones even with the protection > afforded to it by /proc/sys/vm/lowmem_reserve_ratio, it is unlikely that > killing current users will help. The memory is either reclaimable (or > migratable) already, in which case we should not invoke the oom killer at > all, or it is pinned by an application for I/O. Killing such an > application may leave the hardware in an unspecified state and there is no > guarantee that it will be able to make a timely exit. > > Lowmem allocations are now failed in oom conditions when __GFP_NOFAIL is > not used so that the task can perhaps recover or try again later. > > Previously, the heuristic provided some protection for those tasks with > CAP_SYS_RAWIO, but this is no longer necessary since we will not be > killing tasks for the purposes of ISA allocations. > > high_zoneidx is gfp_zone(gfp_flags), meaning that ZONE_NORMAL will be the > default for all allocations that are not __GFP_DMA, __GFP_DMA32, > __GFP_HIGHMEM, and __GFP_MOVABLE on kernels configured to support those > flags. Testing for high_zoneidx being less than ZONE_NORMAL will only > return true for allocations that have either __GFP_DMA or __GFP_DMA32. > > Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx> ack -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>