From: Michal Hocko <mhocko@kernel.org>
To: "C.Wehrmeyer" <c.wehrmeyer@gmx.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>,
linux-mm@kvack.org, linux-kernel <linux-kernel@vger.kernel.org>,
Andrea Arcangeli <aarcange@redhat.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Vlastimil Babka <vbabka@suse.cz>
Subject: Re: PROBLEM: Remapping hugepages mappings causes kernel to return EINVAL
Date: Mon, 23 Oct 2017 20:02:32 +0200 [thread overview]
Message-ID: <20171023180232.luayzqacnkepnm57@dhcp22.suse.cz> (raw)
In-Reply-To: <b138bcf8-0a66-a988-4040-520d767da266@gmx.de>
On Mon 23-10-17 19:52:27, C.Wehrmeyer wrote:
[...]
> > or you can mmap a larger block and
> > munmap the initial unaligned part.
>
> And how is that supposed to be transparent? When I hear "transparent" I
> think of a mechanism which I can put under a system so that it benefits from
> it, while the system does not notice or at least does not need to be aware
> of it. The system also does not need to be changed for it.
How do you expect to get a huge page when the mapping itself is not
properly aligned? Sure if you have a large mapping then you probably do
not care about first and last chunk being not 2MB aligned but in order
to get a THP you really need a 2MB aligned address.
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2017-10-23 18:02 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <93684e4b-9e60-ef3a-ba62-5719fdf7cff9@gmx.de>
2017-10-19 7:34 ` C.Wehrmeyer
2017-10-20 22:42 ` Mike Kravetz
2017-10-23 11:42 ` Michal Hocko
2017-10-23 12:22 ` C.Wehrmeyer
2017-10-23 12:41 ` Michal Hocko
2017-10-23 14:00 ` C.Wehrmeyer
2017-10-23 16:13 ` Michal Hocko
2017-10-23 16:46 ` C.Wehrmeyer
2017-10-23 16:57 ` Michal Hocko
2017-10-23 17:52 ` C.Wehrmeyer
2017-10-23 18:02 ` Michal Hocko [this message]
2017-10-24 7:41 ` C.Wehrmeyer
2017-10-24 8:12 ` Michal Hocko
2017-10-24 8:32 ` C.Wehrmeyer
2017-10-27 14:29 ` Vlastimil Babka
2017-10-27 17:06 ` Mike Kravetz
2017-10-27 17:31 ` Kirill A. Shutemov
2017-10-23 18:51 ` Mike Kravetz
2017-10-24 8:09 ` C.Wehrmeyer
2017-10-07 1:58 C.Wehrmeyer
2017-10-09 16:47 ` Mike Kravetz
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