Hi Peter,

__GFP_MEMALLOC will allow the allocation to disregard the watermarks, 
much like PF_MEMALLOC.

It allows one to pass along the memalloc state in object related allocation
flags as opposed to task related flags, such as sk->sk_allocation.

Is this properly name?
page alloc is always "mem alloc".

you wrote comment as "Use emergency reserves" and 
this flag works to turn on ALLOC_NO_WATERMARKS.

then, __GFP_NO_WATERMARK or __GFP_EMERGENCY are better?