From: Mike Kravetz <mike.kravetz@oracle.com>
To: Mina Almasry <almasrymina@google.com>, Qian Cai <cai@lca.pw>
Cc: Andrew Morton <akpm@linux-foundation.org>,
shuah <shuah@kernel.org>, David Rientjes <rientjes@google.com>,
Shakeel Butt <shakeelb@google.com>,
Greg Thelen <gthelen@google.com>,
open list <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org, linux-kselftest@vger.kernel.org,
cgroups@vger.kernel.org
Subject: Re: [PATCH v12 1/9] hugetlb_cgroup: Add hugetlb_cgroup reservation counter
Date: Tue, 18 Feb 2020 11:14:21 -0800 [thread overview]
Message-ID: <d498012a-ec87-ca48-ed78-5fcdaf372888@oracle.com> (raw)
In-Reply-To: <CAHS8izO5=vKs-v9v=Di3hQXBD41+_YpYarXn1yZu9YE6SR-i6Q@mail.gmail.com>
On 2/18/20 10:35 AM, Mina Almasry wrote:
> On Tue, Feb 18, 2020 at 6:21 AM Qian Cai <cai@lca.pw> wrote:
>>
>> On Tue, 2020-02-11 at 15:19 -0800, Andrew Morton wrote:
>>> On Tue, 11 Feb 2020 13:31:20 -0800 Mina Almasry <almasrymina@google.com> wrote:
>>>
>> [ 7933.806377][T14355] ------------[ cut here ]------------
>> [ 7933.806541][T14355] kernel BUG at mm/hugetlb.c:490!
>> VM_BUG_ON(t - f <= 1);
>> [ 7933.806562][T14355] Oops: Exception in kernel mode, sig: 5 [#1]
<snip>
> Hi Qian,
>
> Yes this VM_BUG_ON was added by a patch in the series ("hugetlb:
> disable region_add file_region coalescing") so it's definitely related
> to the series. I'm taking a look at why this VM_BUG_ON fires. Can you
> confirm you reproduce this by running hugemmap06 from the ltp on a
> powerpc machine? Can I maybe have your config?
>
> Thanks!
Hi Mina,
Looking at the region_chg code again, we do a
resv->adds_in_progress += *out_regions_needed;
and then potentially drop the lock to allocate the needed entries. Could
anopther thread (only adding reservation for a single page) then come in
and notice that there are not enough entries in the cache and hit the
VM_BUG_ON()?
--
Mike Kravetz
next prev parent reply other threads:[~2020-02-18 19:14 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-11 21:31 [PATCH v12 1/9] hugetlb_cgroup: Add hugetlb_cgroup reservation counter Mina Almasry
2020-02-11 21:31 ` [PATCH v12 2/9] hugetlb_cgroup: add interface for charge/uncharge hugetlb reservations Mina Almasry
2020-02-15 0:50 ` Mike Kravetz
2020-02-16 1:21 ` David Rientjes
2020-02-11 21:31 ` [PATCH v12 3/9] hugetlb_cgroup: add reservation accounting for private mappings Mina Almasry
2020-02-11 21:31 ` [PATCH v12 4/9] hugetlb: disable region_add file_region coalescing Mina Almasry
2020-02-15 1:27 ` Mike Kravetz
2020-02-16 1:25 ` David Rientjes
2020-02-11 21:31 ` [PATCH v12 5/9] hugetlb_cgroup: add accounting for shared mappings Mina Almasry
2020-02-16 1:29 ` David Rientjes
2020-02-18 18:07 ` Mike Kravetz
2020-02-11 21:31 ` [PATCH v12 6/9] hugetlb_cgroup: support noreserve mappings Mina Almasry
2020-02-18 20:57 ` Mike Kravetz
2020-02-11 21:31 ` [PATCH v12 7/9] hugetlb: support file_region coalescing again Mina Almasry
2020-02-16 1:29 ` David Rientjes
2020-02-19 3:28 ` Mike Kravetz
2020-02-19 7:54 ` Mina Almasry
2020-02-19 23:36 ` [PATCH] hugetlb: Remove check_coalesce_bug debug code Mina Almasry
2020-02-20 0:07 ` Mike Kravetz
2020-02-11 21:31 ` [PATCH v12 8/9] hugetlb_cgroup: Add hugetlb_cgroup reservation tests Mina Almasry
2020-02-12 8:50 ` Sandipan Das
2020-02-20 0:05 ` Mina Almasry
2020-02-21 0:52 ` Mike Kravetz
2020-02-11 21:31 ` [PATCH v12 9/9] hugetlb_cgroup: Add hugetlb_cgroup reservation docs Mina Almasry
2020-02-20 0:03 ` Mina Almasry
2020-02-20 0:18 ` Mike Kravetz
2020-02-11 23:19 ` [PATCH v12 1/9] hugetlb_cgroup: Add hugetlb_cgroup reservation counter Andrew Morton
2020-02-18 14:21 ` Qian Cai
2020-02-18 18:35 ` Mina Almasry
2020-02-18 18:41 ` Qian Cai
2020-02-18 19:14 ` Mike Kravetz [this message]
2020-02-18 19:25 ` Mina Almasry
2020-02-18 21:36 ` Mina Almasry
2020-02-18 21:41 ` Mike Kravetz
2020-02-18 22:27 ` Mina Almasry
2020-02-19 19:05 ` Mina Almasry
2020-02-19 21:06 ` Andrew Morton
2020-02-20 19:22 ` Mina Almasry
2020-02-21 0:28 ` Andrew Morton
2020-02-21 0:41 ` Mike Kravetz
2020-02-21 1:52 ` Mina Almasry
2020-02-21 20:19 ` Mina Almasry
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