Re: [PATCH 1/6] mm: introduce kv[mz]alloc helpers

From	Michal Hocko <mhocko@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH 1/6] mm: introduce kv[mz]alloc helpers
Date	2017-01-16 20:50 +0100
Message-ID	<t0lrX-58K-5@gated-at.bofh.it> (permalink)
References	<sYPNw-5HL-19@gated-at.bofh.it> <sYPNw-5HL-35@gated-at.bofh.it> <t07fj-3y7-3@gated-at.bofh.it> <t0b9g-67e-13@gated-at.bofh.it> <t0kPh-4OF-43@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

On Mon 16-01-17 11:09:37, John Hubbard wrote:
> 
> 
> On 01/16/2017 12:47 AM, Michal Hocko wrote:
> > On Sun 15-01-17 20:34:13, John Hubbard wrote:
[...]
> > > 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

Thread

[PATCH 0/6 v3] kvmalloc Michal Hocko <mhocko@kernel.org> - 2017-01-12 16:50 +0100
  [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded variants Michal Hocko <mhocko@kernel.org> - 2017-01-12 16:50 +0100
    Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded  variants David Sterba <dsterba@suse.cz> - 2017-01-12 17:00 +0100
    Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded  variants Christian Borntraeger <borntraeger@de.ibm.com> - 2017-01-12 17:10 +0100
    Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded variants Ilya Dryomov <idryomov@gmail.com> - 2017-01-12 18:00 +0100
      Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded  variants Michal Hocko <mhocko@kernel.org> - 2017-01-12 18:20 +0100
    Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded variants Dan Williams <dan.j.williams@intel.com> - 2017-01-12 18:10 +0100
    Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded variants Kees Cook <keescook@chromium.org> - 2017-01-12 18:30 +0100
      Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded  variants Michal Hocko <mhocko@kernel.org> - 2017-01-12 18:40 +0100
        Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded  variants Vlastimil Babka <vbabka@suse.cz> - 2017-01-20 15:00 +0100
          Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded  variants Michal Hocko <mhocko@kernel.org> - 2017-01-24 16:10 +0100
            Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded  variants Vlastimil Babka <vbabka@suse.cz> - 2017-01-25 12:20 +0100
              Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded  variants Michal Hocko <mhocko@kernel.org> - 2017-01-25 14:10 +0100
                Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded variants Ilya Dryomov <idryomov@gmail.com> - 2017-01-25 14:50 +0100
    Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded  variants Michal Hocko <mhocko@kernel.org> - 2017-01-12 18:40 +0100
      Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded  variants Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2017-01-14 04:10 +0100
        Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded  variants Michal Hocko <mhocko@kernel.org> - 2017-01-14 10:10 +0100
    Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded  variants Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2017-01-12 21:20 +0100
    Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded  variants "Dilger, Andreas" <andreas.dilger@intel.com> - 2017-01-13 02:20 +0100
    Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded  variants Leon Romanovsky <leon@kernel.org> - 2017-01-14 12:00 +0100
      Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded  variants Michal Hocko <mhocko@kernel.org> - 2017-01-16 08:40 +0100
        Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded  variants Leon Romanovsky <leon@kernel.org> - 2017-01-16 09:30 +0100
  [PATCH 4/6] ila: simplify a strange allocation pattern Michal Hocko <mhocko@kernel.org> - 2017-01-12 16:50 +0100
  [PATCH 3/6] rhashtable: simplify a strange allocation pattern Michal Hocko <mhocko@kernel.org> - 2017-01-12 16:50 +0100
  [PATCH 1/6] mm: introduce kv[mz]alloc helpers Michal Hocko <mhocko@kernel.org> - 2017-01-12 16:50 +0100
    Re: [PATCH 1/6] mm: introduce kv[mz]alloc helpers John Hubbard <jhubbard@nvidia.com> - 2017-01-16 05:40 +0100
      Re: [PATCH 1/6] mm: introduce kv[mz]alloc helpers Michal Hocko <mhocko@kernel.org> - 2017-01-16 09:50 +0100
        Re: [PATCH 1/6] mm: introduce kv[mz]alloc helpers John Hubbard <jhubbard@nvidia.com> - 2017-01-16 20:10 +0100
          Re: [PATCH 1/6] mm: introduce kv[mz]alloc helpers Michal Hocko <mhocko@kernel.org> - 2017-01-16 20:50 +0100
            Re: [PATCH 1/6] mm: introduce kv[mz]alloc helpers John Hubbard <jhubbard@nvidia.com> - 2017-01-16 22:30 +0100
              Re: [PATCH 1/6] mm: introduce kv[mz]alloc helpers Michal Hocko <mhocko@kernel.org> - 2017-01-16 22:50 +0100
                Re: [PATCH 1/6] mm: introduce kv[mz]alloc helpers John Hubbard <jhubbard@nvidia.com> - 2017-01-16 23:00 +0100
                Re: [PATCH 1/6] mm: introduce kv[mz]alloc helpers Michal Hocko <mhocko@kernel.org> - 2017-01-17 09:00 +0100
                Re: [PATCH 1/6] mm: introduce kv[mz]alloc helpers John Hubbard <jhubbard@nvidia.com> - 2017-01-18 07:10 +0100
                Re: [PATCH 1/6] mm: introduce kv[mz]alloc helpers Michal Hocko <mhocko@kernel.org> - 2017-01-18 09:30 +0100
                Re: [PATCH 1/6] mm: introduce kv[mz]alloc helpers John Hubbard <jhubbard@nvidia.com> - 2017-01-19 09:40 +0100
                Re: [PATCH 1/6] mm: introduce kv[mz]alloc helpers Michal Hocko <mhocko@kernel.org> - 2017-01-19 10:10 +0100
                Re: [PATCH 1/6] mm: introduce kv[mz]alloc helpers John Hubbard <jhubbard@nvidia.com> - 2017-01-19 10:20 +0100
                Re: [PATCH 1/6] mm: introduce kv[mz]alloc helpers Michal Hocko <mhocko@kernel.org> - 2017-01-19 11:00 +0100
                Re: [PATCH 1/6] mm: introduce kv[mz]alloc helpers John Hubbard <jhubbard@nvidia.com> - 2017-01-19 22:30 +0100
    Re: [PATCH 1/6] mm: introduce kv[mz]alloc helpers Michal Hocko <mhocko@kernel.org> - 2017-01-26 13:20 +0100
      Re: [PATCH 1/6] mm: introduce kv[mz]alloc helpers Vlastimil Babka <vbabka@suse.cz> - 2017-01-30 10:10 +0100
  Re: [PATCH 0/6 v3] kvmalloc Michal Hocko <mhocko@kernel.org> - 2017-01-24 16:20 +0100
    Re: [PATCH 0/6 v3] kvmalloc Eric Dumazet <eric.dumazet@gmail.com> - 2017-01-24 17:10 +0100
      Re: [PATCH 0/6 v3] kvmalloc Michal Hocko <mhocko@kernel.org> - 2017-01-25 14:20 +0100
    Re: [PATCH 0/6 v3] kvmalloc Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2017-01-24 20:20 +0100
      Re: [PATCH 0/6 v3] kvmalloc Michal Hocko <mhocko@kernel.org> - 2017-01-25 14:20 +0100
        Re: [PATCH 0/6 v3] kvmalloc Michal Hocko <mhocko@kernel.org> - 2017-01-25 14:30 +0100

csiph-web