From: Dan Williams <dan.j.williams@intel.com>
To: alexander.h.duyck@linux.intel.com
Cc: "Linux MM" <linux-mm@kvack.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
linux-nvdimm <linux-nvdimm@lists.01.org>,
"Pasha Tatashin" <pavel.tatashin@microsoft.com>,
"Michal Hocko" <mhocko@suse.com>,
"Dave Jiang" <dave.jiang@intel.com>,
"Dave Hansen" <dave.hansen@intel.com>,
"Jérôme Glisse" <jglisse@redhat.com>,
rppt@linux.vnet.ibm.com, "Logan Gunthorpe" <logang@deltatee.com>,
"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 15:00:57 -0700 [thread overview]
Message-ID: <CAPcyv4i_x4NO2_qsfgwsgii9zmjZ43gJW6OCLpf=CweztRtZZw@mail.gmail.com> (raw)
In-Reply-To: <379e1d22-4194-6744-9e80-897b6ba126e9@linux.intel.com>
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.
next prev parent reply other threads:[~2018-10-08 22:01 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 [this message]
2018-10-08 22:07 ` Alexander Duyck
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
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