From: Eric Dumazet <edumazet@google.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
Tom Herbert <tom@herbertland.com>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: weird allocation pattern in alloc_ila_locks
Date: Sat, 7 Jan 2017 10:37:41 -0800 [thread overview]
Message-ID: <CANn89iL7JTkV_r9Wqqcrsz1GJmTfWtxD1TUV1YOKsv3rwN-+vQ@mail.gmail.com> (raw)
In-Reply-To: <20170107092746.GC5047@dhcp22.suse.cz>
On Sat, Jan 7, 2017 at 1:27 AM, Michal Hocko <mhocko@kernel.org> wrote:
> On Fri 06-01-17 14:14:49, Eric Dumazet wrote:
>> I believe the intent was to get NUMA spreading, a bit like what we have
>> in alloc_large_system_hash() when hashdist == HASHDIST_DEFAULT
>
> Hmm, I am not sure this works as expected then. Because it is more
> likely that all pages backing the vmallocked area will come from the
> local node than spread around more nodes. Or did I miss your point?
Well, you missed that vmalloc() is aware of NUMA policies.
If current process has requested interleave on 2 nodes (as it is done
at boot time on a dual node system),
then vmalloc() of 8 pages will allocate 4 pages on each node.
If you force/attempt a kmalloc() of one order-3 page, chances are very
high to get all memory on one single node.
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next prev parent reply other threads:[~2017-01-07 18:37 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-06 9:51 Michal Hocko
2017-01-06 10:04 ` Michal Hocko
2017-01-06 12:16 ` Michal Hocko
2017-01-06 22:14 ` Eric Dumazet
2017-01-07 9:27 ` Michal Hocko
2017-01-07 18:37 ` Eric Dumazet [this message]
2017-01-09 9:58 ` Michal Hocko
2017-01-09 14:31 ` Eric Dumazet
2017-01-09 14:41 ` Michal Hocko
2017-01-09 14:43 ` [PATCH 1/2] rhashtable: simplify a strange allocation pattern Michal Hocko
2017-01-09 14:43 ` [PATCH 2/2] ila: " Michal Hocko
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