From: Alexander Duyck <alexander.h.duyck@linux.intel.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: "Pasha Tatashin" <pavel.tatashin@microsoft.com>,
"Michal Hocko" <mhocko@suse.com>,
linux-nvdimm <linux-nvdimm@lists.01.org>,
"Dave Hansen" <dave.hansen@intel.com>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
"Linux MM" <linux-mm@kvack.org>,
"Jérôme Glisse" <jglisse@redhat.com>,
rppt@linux.vnet.ibm.com,
"Andrew Morton" <akpm@linux-foundation.org>,
"Ingo Molnar" <mingo@kernel.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH v5 4/4] mm: Defer ZONE_DEVICE page initialization to the point where we init pgmap
Date: Mon, 8 Oct 2018 15:07:42 -0700 [thread overview]
Message-ID: <cdb5524c-371f-17b0-4804-52f237074f58@linux.intel.com> (raw)
In-Reply-To: <CAPcyv4i_x4NO2_qsfgwsgii9zmjZ43gJW6OCLpf=CweztRtZZw@mail.gmail.com>
On 10/8/2018 3:00 PM, Dan Williams wrote:
> On Mon, Oct 8, 2018 at 2:48 PM Alexander Duyck
> <alexander.h.duyck@linux.intel.com> wrote:
>>
>> On 10/8/2018 2:01 PM, Dan Williams wrote:
>>> On Tue, Sep 25, 2018 at 1:29 PM Alexander Duyck
>>> <alexander.h.duyck@linux.intel.com> wrote:
>>>>
>>>> The ZONE_DEVICE pages were being initialized in two locations. One was with
>>>> the memory_hotplug lock held and another was outside of that lock. The
>>>> problem with this is that it was nearly doubling the memory initialization
>>>> time. Instead of doing this twice, once while holding a global lock and
>>>> once without, I am opting to defer the initialization to the one outside of
>>>> the lock. This allows us to avoid serializing the overhead for memory init
>>>> and we can instead focus on per-node init times.
>>>>
>>>> One issue I encountered is that devm_memremap_pages and
>>>> hmm_devmmem_pages_create were initializing only the pgmap field the same
>>>> way. One wasn't initializing hmm_data, and the other was initializing it to
>>>> a poison value. Since this is something that is exposed to the driver in
>>>> the case of hmm I am opting for a third option and just initializing
>>>> hmm_data to 0 since this is going to be exposed to unknown third party
>>>> drivers.
>>>>
>>>> Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
>>>> Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
>>>> ---
>>>>
>>>> v4: Moved moved memmap_init_zone_device to below memmmap_init_zone to avoid
>>>> merge conflicts with other changes in the kernel.
>>>> v5: No change
>>>
>>> This patch appears to cause a regression in the "create.sh" unit test
>>> in the ndctl test suite.
>>
>> So all you had to do is run the create.sh script to see the issue? I
>> just want to confirm there isn't any additional information needed
>> before I try chasing this down.
>
> From the ndctl source tree run:
>
> make -j TESTS="create.sh" check
>
> ...the readme has some more setup instructions:
> https://github.com/pmem/ndctl/blob/master/README.md
>
> 0day has sometimes run this test suite automatically, but we need to
> get that more robust because setting up this environment is a bit of a
> hoop to jump through with the need to setup the nfit_test module.
>
>>> I tried to reproduce on -next with:
>>>
>>> 2302f5ee215e mm: defer ZONE_DEVICE page initialization to the point
>>> where we init pgmap
>>>
>>> ...but -next does not even boot for me at that commit.
>>
>> What version of -next? There are a couple of patches probably needed
>> depending on which version you are trying to boot.
>
> Today's -next, but backed up to that above commit. I was also seeing
> CONFIG_DEBUG_LIST spamming the logs, and a crash in the crypto layer.
>
>>> Here is a warning signature that proceeds a hang with this patch
>>> applied against v4.19-rc6:
>>>
>>> percpu ref (blk_queue_usage_counter_release) <= 0 (-1530626) after
>>> switching to atomic
>>> WARNING: CPU: 24 PID: 7346 at lib/percpu-refcount.c:155
>>> percpu_ref_switch_to_atomic_rcu+0x1f7/0x200
>>> CPU: 24 PID: 7346 Comm: modprobe Tainted: G OE 4.19.0-rc6+ #2458
>>> [..]
>>> RIP: 0010:percpu_ref_switch_to_atomic_rcu+0x1f7/0x200
>>> [..]
>>> Call Trace:
>>> <IRQ>
>>> ? percpu_ref_reinit+0x140/0x140
>>> rcu_process_callbacks+0x273/0x880
>>> __do_softirq+0xd2/0x428
>>> irq_exit+0xf6/0x100
>>> smp_apic_timer_interrupt+0xa2/0x220
>>> apic_timer_interrupt+0xf/0x20
>>> </IRQ>
>>> RIP: 0010:lock_acquire+0xb8/0x1a0
>>> [..]
>>> ? __put_page+0x55/0x150
>>> ? __put_page+0x55/0x150
>>> __put_page+0x83/0x150
>>> ? __put_page+0x55/0x150
>>> devm_memremap_pages_release+0x194/0x250
>>> release_nodes+0x17c/0x2c0
>>> device_release_driver_internal+0x1a2/0x250
>>> driver_detach+0x3a/0x70
>>> bus_remove_driver+0x58/0xd0
>>> __x64_sys_delete_module+0x13f/0x200
>>> ? trace_hardirqs_off_thunk+0x1a/0x1c
>>> do_syscall_64+0x60/0x210
>>> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>>>
>>
>> So it looks like we are tearing down memory when this is triggered. Do
>> we know if this is at the end of the test or if this is running in
>> parallel with anything?
>
> Should not be running in parallel with anything this test is
> performing a series of namespace setup and teardown events.
>
> Wait, where did the call to "percpu_ref_get()" go? I think that's the bug.
Actually I think you are probably right. Do you want to get that or
should I. Should be a quick patch since you could probably just add a
call to percpu_ref_get_many to hold a reference for each page in the
range of device pages before calling memmap_init_zone_device.
- Alex
_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm
next prev parent reply other threads:[~2018-10-08 22:07 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-25 20:18 [PATCH v5 0/4] Address issues slowing persistent memory initialization Alexander Duyck
2018-09-25 20:19 ` [PATCH v5 1/4] mm: Remove now defunct NO_BOOTMEM from depends list for deferred init Alexander Duyck
2018-09-25 21:05 ` Mike Rapoport
2018-09-25 20:20 ` [PATCH v5 2/4] mm: Provide kernel parameter to allow disabling page init poisoning Alexander Duyck
2018-09-25 20:26 ` Dave Hansen
2018-09-25 20:38 ` Alexander Duyck
2018-09-25 22:14 ` Dave Hansen
2018-09-25 22:27 ` Alexander Duyck
2018-09-26 7:38 ` Michal Hocko
2018-09-26 15:24 ` Alexander Duyck
2018-09-26 15:39 ` Michal Hocko
2018-09-26 15:41 ` Dave Hansen
2018-09-26 16:18 ` Alexander Duyck
2018-09-26 15:36 ` Dave Hansen
2018-09-26 22:36 ` Andrew Morton
2018-09-25 20:20 ` [PATCH v5 3/4] mm: Create non-atomic version of SetPageReserved for init use Alexander Duyck
2018-09-25 20:21 ` [PATCH v5 4/4] mm: Defer ZONE_DEVICE page initialization to the point where we init pgmap Alexander Duyck
2018-09-26 7:55 ` Michal Hocko
2018-09-26 18:25 ` Alexander Duyck
2018-09-26 18:52 ` Dan Williams
2018-09-27 11:20 ` Michal Hocko
2018-09-27 11:09 ` Michal Hocko
2018-09-27 12:25 ` Oscar Salvador
2018-09-27 13:13 ` Michal Hocko
2018-09-27 14:50 ` Oscar Salvador
2018-09-27 15:41 ` David Hildenbrand
2018-09-28 8:12 ` Oscar Salvador
2018-09-28 8:44 ` Oscar Salvador
2018-09-28 15:50 ` Dan Williams
2018-09-27 12:32 ` Oscar Salvador
2018-10-08 21:01 ` Dan Williams
2018-10-08 21:38 ` Alexander Duyck
2018-10-08 22:00 ` Dan Williams
2018-10-08 22:07 ` Alexander Duyck [this message]
2018-10-08 22:36 ` Alexander Duyck
2018-10-08 22:59 ` Dan Williams
2018-10-08 23:34 ` [mm PATCH] memremap: Fix reference count for pgmap in devm_memremap_pages Alexander Duyck
2018-10-09 0:20 ` Dan Williams
2018-10-09 17:00 ` [PATCH v5 4/4] mm: Defer ZONE_DEVICE page initialization to the point where we init pgmap Yi Zhang
2018-10-09 18:04 ` Dan Williams
2018-10-09 20:26 ` Alexander Duyck
2018-10-09 21:19 ` Dan Williams
2018-10-10 12:52 ` Yi Zhang
2018-10-10 15:27 ` Alexander Duyck
2018-10-11 8:17 ` Yi Zhang
2018-10-10 9:58 ` Michal Hocko
2018-10-10 16:39 ` Alexander Duyck
2018-10-10 17:24 ` Michal Hocko
2018-10-10 17:39 ` Alexander Duyck
2018-10-10 17:53 ` Michal Hocko
2018-10-10 18:13 ` Alexander Duyck
2018-10-10 18:52 ` Michal Hocko
2018-10-11 8:55 ` Michal Hocko
2018-10-11 17:38 ` Alexander Duyck
2018-10-11 18:22 ` Dan Williams
2018-10-17 7:52 ` Michal Hocko
2018-10-17 15:02 ` Alexander Duyck
2018-10-29 14:12 ` Michal Hocko
2018-10-29 15:59 ` Alexander Duyck
2018-10-29 16:35 ` Michal Hocko
2018-10-29 17:01 ` Alexander Duyck
2018-10-29 17:24 ` Michal Hocko
2018-10-29 17:34 ` Dan Williams
2018-10-29 17:45 ` Michal Hocko
2018-10-29 17:42 ` Alexander Duyck
2018-10-29 18:18 ` Michal Hocko
2018-10-29 19:59 ` Alexander Duyck
2018-10-30 6:29 ` Michal Hocko
2018-10-30 6:55 ` Dan Williams
2018-10-30 8:17 ` Michal Hocko
2018-10-30 15:57 ` Dan Williams
2018-10-30 8:05 ` Oscar Salvador
2018-10-29 15:49 ` Dan Williams
2018-10-29 15:56 ` Michal Hocko
2018-10-10 18:18 ` Dan Williams
2018-10-11 8:39 ` Yi Zhang
2018-10-11 15:38 ` Alexander Duyck
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=cdb5524c-371f-17b0-4804-52f237074f58@linux.intel.com \
--to=alexander.h.duyck@linux.intel.com \
--cc=akpm@linux-foundation.org \
--cc=dan.j.williams@intel.com \
--cc=dave.hansen@intel.com \
--cc=jglisse@redhat.com \
--cc=kirill.shutemov@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-nvdimm@lists.01.org \
--cc=mhocko@suse.com \
--cc=mingo@kernel.org \
--cc=pavel.tatashin@microsoft.com \
--cc=rppt@linux.vnet.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).