On Mon, 2 Mar 2015, Michal Hocko wrote: > This basically reverts 47def82672b3 (jbd2: Remove __GFP_NOFAIL from jbd2 > layer). The deprecation of __GFP_NOFAIL was a bad choice because it led > to open coding the endless loop around the allocator rather than > removing the dependency on the non failing allocation. So the > deprecation was a clear failure and the reality tells us that > __GFP_NOFAIL is not even close to go away. > > It is still true that __GFP_NOFAIL allocations are generally discouraged > and new uses should be evaluated and an alternative (pre-allocations or > reservations) should be considered but it doesn't make any sense to lie > the allocator about the requirements. Allocator can take steps to help > making a progress if it knows the requirements. > The changelog should state that this only changes the source code, there is no functional change since alloc_buffer_head() and kmem_cache_zalloc(transaction_cache) are already implicitly nofail due to the allocation order. The failure code added by the commit you cite are never executed. I agree that if the implementation of the page allocator were to change with respect to PAGE_ALLOC_COSTLY_ORDER that we'd need __GFP_NOFAIL and that such an allocation is better handled in the page allocator. > Signed-off-by: Michal Hocko <mhocko@xxxxxxx> Acked-by: David Rientjes <rientjes@xxxxxxxxxx> GFP_NOFS|__GFP_NOFAIL is scary. -- 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>