On Mon 16-01-17 11:09:37, John Hubbard wrote:

On 01/16/2017 12:47 AM, Michal Hocko wrote:

quoted

On Sun 15-01-17 20:34:13, John Hubbard wrote:

[...]

quoted

quoted

Is that "Reclaim modifiers" line still true, or is it a leftover from an
earlier approach? I am having trouble reconciling it with rest of the
patchset, because:

a) the flags argument below is effectively passed on to either kmalloc_node
(possibly adding, but not removing flags), or to __vmalloc_node_flags.

The above only says thos are _unsupported_ - in other words the behavior
is not defined. Even if flags are passed down to kmalloc resp. vmalloc
it doesn't mean they are used that way.  Remember that vmalloc uses
some hardcoded GFP_KERNEL allocations.  So while I could be really
strict about this and mask away these flags I doubt this is worth the
additional code.

I do wonder about passing those flags through to kmalloc. Maybe it is worth
stripping out __GFP_NORETRY and __GFP_NOFAIL, after all. It provides some
insulation from any future changes to the implementation of kmalloc, and it
also makes the documentation more believable.

I am not really convinced that we should take an extra steps for these
flags. There are no existing users for those flags and new users should
follow the documentation.

-- 
Michal Hocko
SUSE Labs

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