From: Brian Geffon <bgeffon@google.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Andrew Morton <akpm@linux-foundation.org>,
"Michael S . Tsirkin" <mst@redhat.com>,
Arnd Bergmann <arnd@arndb.de>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
linux-api@vger.kernel.org, Andy Lutomirski <luto@amacapital.net>,
Andrea Arcangeli <aarcange@redhat.com>,
Sonny Rao <sonnyrao@google.com>, Minchan Kim <minchan@kernel.org>,
Joel Fernandes <joel@joelfernandes.org>,
Yu Zhao <yuzhao@google.com>, Jesse Barnes <jsbarnes@google.com>
Subject: Re: [PATCH v2] mm: Add MREMAP_DONTUNMAP to mremap().
Date: Sat, 1 Feb 2020 22:03:37 +0100 [thread overview]
Message-ID: <CADyq12ysX9Ce+CUr=Cs-LcYrJDeYubDfZy2-GYFHAz111J8QBA@mail.gmail.com> (raw)
In-Reply-To: <20200129104655.egvpavc2tzozlbqe@box>
Hi Kirill,
On Wed, Jan 29, 2020 at 11:46 AM Kirill A. Shutemov
<kirill@shutemov.name> wrote:
> And based on the use case you probably don't really need 'fixed'
> semantics all the time. The user should be fine with moving the mapping
> *somewhere*, not neccessary to the given address
This is true and and it simplifies things a bit as for the outlined
use cases the user would not be required to mmap the destination
before hand. Part of the reason I chose to require MREMAP_FIXED was
because mremap need not move the mapping if it can shrink/grow in
place and it seemed a bit awkward to have "MUSTMOVE" behavior without
MAP_FIXED. I'll make this change to drop the requirement on
MREMAP_FIXED in my next patch.
> BTW, name of the flag is confusing. My initial reaction was that it is
> variant of MREMAP_FIXED that does't anything at the target address.
> Like MAP_FIXED vs. MAP_FIXED_NOREPLACE.
>
> Any better options for the flag name? (I have none)
I see your point. Perhaps MREMAP_MOVEPAGES or MREMAP_KEEP_SOURCE? I
struggle to come up with a single name that encapsulates this behavior
but I'll try to think of other ideas before I mail the next patch.
Given that we will drop the requirement on MREMAP_FIXED, perhaps
MOVEPAGES is the better option as it captures that the mapping WILL be
moved?
Thanks again for taking the time to look at this.
Best,
Brian
next prev parent reply other threads:[~2020-02-01 21:04 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-23 1:46 [PATCH] mm: Add MREMAP_DONTUNMAP to mremap() Brian Geffon
2020-01-23 3:02 ` Andy Lutomirski
2020-01-23 19:03 ` Brian Geffon
2020-01-24 19:06 ` [PATCH v2] " Brian Geffon
2020-01-26 5:16 ` Nathan Chancellor
2020-01-27 2:21 ` Brian Geffon
2020-01-26 22:06 ` Kirill A. Shutemov
2020-01-28 1:35 ` Brian Geffon
2020-01-29 10:46 ` Kirill A. Shutemov
2020-02-01 21:03 ` Brian Geffon [this message]
2020-02-02 4:17 ` Brian Geffon
2020-02-03 13:09 ` Kirill A. Shutemov
2020-02-07 20:42 ` Brian Geffon
2020-02-10 10:35 ` Kirill A. Shutemov
2020-01-27 10:13 ` Florian Weimer
2020-01-27 22:33 ` Brian Geffon
2020-01-30 12:19 ` Florian Weimer
2020-01-27 4:46 ` [PATCH] " Dan Carpenter
2020-01-27 5:30 ` [PATCH v3] " Brian Geffon
2020-01-28 15:26 ` Will Deacon
2020-01-30 10:12 ` Will Deacon
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