From: Michal Hocko <mhocko@kernel.org>
To: John Hubbard <jhubbard@nvidia.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
David Rientjes <rientjes@google.com>,
Mel Gorman <mgorman@suse.de>,
Johannes Weiner <hannes@cmpxchg.org>,
Al Viro <viro@zeniv.linux.org.uk>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
Anatoly Stepanov <astepanov@cloudlinux.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Mike Snitzer <snitzer@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Theodore Ts'o <tytso@mit.edu>
Subject: Re: [PATCH 1/6] mm: introduce kv[mz]alloc helpers
Date: Thu, 19 Jan 2017 10:56:12 +0100 [thread overview]
Message-ID: <20170119095610.GL30786@dhcp22.suse.cz> (raw)
In-Reply-To: <f1b2ce94-8448-f744-e9d0-c65f6f68fe18@nvidia.com>
On Thu 19-01-17 01:09:35, John Hubbard wrote:
[...]
> So that leaves us with maybe this for documentation?
>
> * Reclaim modifiers - __GFP_NORETRY and __GFP_NOFAIL should not be passed in.
> * Passing in __GFP_REPEAT is supported, and will cause the following behavior:
> * for larger (>64KB) allocations, the first part (kmalloc) will do some
> * retrying, before falling back to vmalloc.
I am worried this is just too vague. It doesn't really help user to
decide whether "do some retrying" is what he really want's or needs.
So I would rather see the following.
"
* Reclaim modifiers - __GFP_NORETRY and __GFP_NOFAIL are not supported. __GFP_REPEAT
* is supported only for large (>32kB) allocations and it should be used when using
* kmalloc is preferable because vmalloc fallback has visible performance drawbacks.
"
I would also add
"
Any use of gfp flags outside of GFP_KERNEL should be consulted with mm people.
"
Does it sound any better?
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2017-01-19 9:56 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-12 15:37 [PATCH 0/6 v3] kvmalloc Michal Hocko
2017-01-12 15:37 ` [PATCH 1/6] mm: introduce kv[mz]alloc helpers Michal Hocko
2017-01-16 4:34 ` John Hubbard
2017-01-16 8:47 ` Michal Hocko
2017-01-16 19:09 ` John Hubbard
2017-01-16 19:40 ` Michal Hocko
2017-01-16 21:15 ` John Hubbard
2017-01-16 21:48 ` Michal Hocko
2017-01-16 21:57 ` John Hubbard
2017-01-17 7:51 ` Michal Hocko
2017-01-18 5:59 ` John Hubbard
2017-01-18 8:21 ` Michal Hocko
2017-01-19 8:37 ` John Hubbard
2017-01-19 8:45 ` Michal Hocko
2017-01-19 9:09 ` John Hubbard
2017-01-19 9:56 ` Michal Hocko [this message]
2017-01-19 21:28 ` John Hubbard
2017-01-26 12:09 ` Michal Hocko
2017-01-30 8:42 ` Vlastimil Babka
2017-01-12 15:37 ` [PATCH 2/6] mm: support __GFP_REPEAT in kvmalloc_node for >=64kB Michal Hocko
2017-01-12 16:12 ` Michael S. Tsirkin
2017-01-14 2:42 ` Tetsuo Handa
2017-01-14 8:45 ` Michal Hocko
2017-01-24 15:40 ` Michael S. Tsirkin
2017-01-12 15:37 ` [PATCH 3/6] rhashtable: simplify a strange allocation pattern Michal Hocko
2017-01-12 15:37 ` [PATCH 4/6] ila: " Michal Hocko
2017-01-12 15:37 ` [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded variants Michal Hocko
2017-01-12 15:57 ` David Sterba
2017-01-12 16:05 ` Christian Borntraeger
2017-01-12 16:54 ` Ilya Dryomov
2017-01-12 17:18 ` Michal Hocko
2017-01-12 17:00 ` Dan Williams
2017-01-12 17:26 ` Kees Cook
2017-01-12 17:37 ` Michal Hocko
2017-01-20 13:41 ` Vlastimil Babka
2017-01-24 15:00 ` Michal Hocko
2017-01-25 11:15 ` Vlastimil Babka
2017-01-25 13:09 ` Michal Hocko
2017-01-25 13:40 ` Ilya Dryomov
2017-01-12 17:29 ` Michal Hocko
2017-01-14 3:01 ` Tetsuo Handa
2017-01-14 8:49 ` Michal Hocko
2017-01-12 20:14 ` Boris Ostrovsky
2017-01-13 1:11 ` Dilger, Andreas
2017-01-14 10:56 ` Leon Romanovsky
2017-01-16 7:33 ` Michal Hocko
2017-01-16 8:28 ` Leon Romanovsky
2017-01-16 8:18 ` Tariq Toukan
2017-01-12 15:37 ` [RFC PATCH 6/6] net: use kvmalloc with __GFP_REPEAT rather than open coded variant Michal Hocko
2017-01-24 15:17 ` [PATCH 0/6 v3] kvmalloc Michal Hocko
2017-01-24 16:00 ` Eric Dumazet
2017-01-25 13:10 ` Michal Hocko
2017-01-24 19:17 ` Alexei Starovoitov
2017-01-25 13:10 ` Michal Hocko
2017-01-25 13:21 ` Michal Hocko
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