From: Mike Kravetz <mike.kravetz@oracle.com>
To: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Laura Abbott <labbott@redhat.com>
Cc: bugzilla-daemon@bugzilla.kernel.org,
tpearson@raptorengineering.com,
"Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Subject: Re: [Bug 201085] New: Kernel allows mlock() on pages in CMA without migrating pages out of CMA first
Date: Wed, 12 Sep 2018 15:19:32 -0700 [thread overview]
Message-ID: <6d38e089-6df4-ead7-4a9d-7277a2db5d7c@oracle.com> (raw)
In-Reply-To: <20180912124727.fccccf432d2d8163ead79288@linux-foundation.org>
On 09/12/2018 12:47 PM, Andrew Morton wrote:
>
> (switched to email. Please respond via emailed reply-to-all, not via the
> bugzilla web interface).
>
> On Tue, 11 Sep 2018 03:59:11 +0000 bugzilla-daemon@bugzilla.kernel.org wrote:
>
>> https://bugzilla.kernel.org/show_bug.cgi?id=201085
>>
>> Bug ID: 201085
>> Summary: Kernel allows mlock() on pages in CMA without
>> migrating pages out of CMA first
>> Product: Memory Management
>> Version: 2.5
>> Kernel Version: 4.18
>> Hardware: All
>> OS: Linux
>> Tree: Mainline
>> Status: NEW
>> Severity: normal
>> Priority: P1
>> Component: Page Allocator
>> Assignee: akpm@linux-foundation.org
>> Reporter: tpearson@raptorengineering.com
>> Regression: No
>>
>> Pages allocated in CMA are not migrated out of CMA when non-CMA memory is
>> available and locking is attempted via mlock(). This can result in rapid
>> exhaustion of the CMA pool if memory locking is used by an application with
>> large memory requirements such as QEMU.
>>
>> To reproduce, on a dual-CPU (NUMA) POWER9 host try to launch a VM with mlock=on
>> and 1/2 or more of physical memory allocated to the guest. Observe full CMA
>> pool depletion occurs despite plenty of normal free RAM available.
>>
>> --
>> You are receiving this mail because:
>> You are the assignee for the bug.
IIRC, Aneesh is working on some powerpc IOMMU patches for a similar issue
(long term pinning of cma pages). Added him on Cc:
https://lkml.kernel.org/r/20180906054342.25094-2-aneesh.kumar@linux.ibm.com
This report seems to be suggesting a more general solution/change. Wondering
if there is any overlap with this and Aneesh's work.
--
Mike Kravetz
next prev parent reply other threads:[~2018-09-12 22:19 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-201085-27@https.bugzilla.kernel.org/>
2018-09-12 19:47 ` [Bug 201085] New: Kernel allows mlock() on pages in CMA without migrating pages out of CMA first Andrew Morton
2018-09-12 22:19 ` Mike Kravetz [this message]
2018-09-14 3:09 ` Aneesh Kumar K.V
2018-09-14 3:12 ` Aneesh Kumar K.V
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