From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Brian Geffon <bgeffon@google.com>
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>,
Will Deacon <will@kernel.org>,
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>,
Nathan Chancellor <natechancellor@gmail.com>,
Florian Weimer <fweimer@redhat.com>
Subject: Re: [PATCH v4] mm: Add MREMAP_DONTUNMAP to mremap().
Date: Thu, 13 Feb 2020 15:08:13 +0300 [thread overview]
Message-ID: <20200213120813.myanzyjmpyzixghf@box> (raw)
In-Reply-To: <CADyq12wcwvRLwueucHFV2ErL67etOJdFGYQdqVFM2WAeOkMGQA@mail.gmail.com>
On Mon, Feb 10, 2020 at 06:12:39AM -0800, Brian Geffon wrote:
> Hi Kirill,
> If the old_len == new_len then there is no change in the number of
> locked pages they just moved, if the new_len < old_len then the
> process of unmapping (new_len - old_len) bytes from the old mapping
> will handle the locked page accounting. So in this special case where
> we're growing the VMA, vma_to_resize() will enforce that growing the
> vma doesn't exceed RLIMIT_MEMLOCK, but vma_to_resize() doesn't handle
> incrementing mm->locked_bytes which is why we have that special case
> incrementing it here.
But if you do the operation for the VM_LOCKED vma, you'll have two locked
VMA's now, right? Where do you account the old locked vma you left behind?
--
Kirill A. Shutemov
next prev parent reply other threads:[~2020-02-13 12:07 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-07 20:18 [PATCH v4] mm: Add MREMAP_DONTUNMAP to mremap() Brian Geffon
2020-02-07 20:21 ` [PATCH] mremap.2: Add information for MREMAP_DONTUNMAP Brian Geffon
2020-02-13 12:55 ` Christian Brauner
[not found] ` <20200207201856.46070-1-bgeffon-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2020-02-10 1:21 ` [PATCH v4] mm: Add MREMAP_DONTUNMAP to mremap() Andrew Morton
[not found] ` <20200209172140.aa60488e10e0408c4f74f11b-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
2020-02-10 18:38 ` Brian Geffon
2020-02-10 10:45 ` Kirill A. Shutemov
2020-02-10 14:12 ` Brian Geffon
2020-02-13 12:08 ` Kirill A. Shutemov [this message]
2020-02-13 18:20 ` Brian Geffon
2020-02-14 0:36 ` Kirill A. Shutemov
2020-02-11 23:13 ` Daniel Colascione
[not found] ` <CAKOZuevHH1pamEKy5n5RLWDP=tHk6_9bR+g3G+HKnqm_srHvrw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2020-02-11 23:32 ` Brian Geffon
[not found] ` <CADyq12ySxau=SyyNp6VSbwmvRm6Kq1=Y62wTbQZoEAQ1XaXcuw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2020-02-11 23:53 ` Daniel Colascione
2020-02-14 4:09 ` [PATCH v5 1/2] " Brian Geffon
2020-02-14 4:09 ` [PATCH v5 2/2] selftest: Add MREMAP_DONTUNMAP selftest Brian Geffon
2020-02-14 14:28 ` [PATCH v5 1/2] mm: Add MREMAP_DONTUNMAP to mremap() Kirill A. Shutemov
2020-02-14 18:46 ` Brian Geffon
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