On Wed 03-06-15 22:04:22, Tetsuo Handa wrote: [...] > Michal Hocko wrote: > > Initialize the default to (mapping_gfp_mask | GFP_IOFS) because this > > should be safe from the page fault path normally. Why do we care > > about mapping_gfp_mask at all then? Because this doesn't hold only > > reclaim protection flags but it also might contain zone and movability > > restrictions (GFP_DMA32, __GFP_MOVABLE and others) so we have to respect > > those. > > [2/2] says that mapping_gfp_mask(mapping) might contain bits which are not > in !GFP_KERNEL. If we do > > GFP_KERNEL & mapping_gfp_mask(mapping) > > we will drop such bits and will cause problems. No we won't. > Thus, "GFP_KERNEL" > in patch [1/1] should be replaced with "mapping_gfp_mask(mapping)" than > "GFP_KERNEL & mapping_gfp_mask(mapping)" ? Those gfp_masks are for LRU handling and that is GFP_KERNEL by default. We only need to drop those which are not compatible with mapping_gfp_mask. We do not care about __GFP_MOVABLE, GFP_DMA32 etc... -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>