Re: [PATCH v11 00/25] mm/gup: track dma-pinned pages: FOLL_PIN

From: John Hubbard <jhubbard@nvidia.com>
To: Leon Romanovsky <leon@kernel.org>
Cc: "Jason Gunthorpe" <jgg@ziepe.ca>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Al Viro" <viro@zeniv.linux.org.uk>,
	"Alex Williamson" <alex.williamson@redhat.com>,
	"Benjamin Herrenschmidt" <benh@kernel.crashing.org>,
	"Björn Töpel" <bjorn.topel@intel.com>,
	"Christoph Hellwig" <hch@infradead.org>,
	"Dan Williams" <dan.j.williams@intel.com>,
	"Daniel Vetter" <daniel@ffwll.ch>,
	"Dave Chinner" <david@fromorbit.com>,
	"David Airlie" <airlied@linux.ie>,
	"David S . Miller" <davem@davemloft.net>,
	"Ira Weiny" <ira.weiny@intel.com>, "Jan Kara" <jack@suse.cz>,
	"Jens Axboe" <axboe@kernel.dk>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"Jérôme Glisse" <jglisse@redhat.com>,
	"Magnus Karlsson" <magnus.karlsson@intel.com>,
	"Mauro Carvalho Chehab" <mchehab@kernel.org>,
	"Michael Ellerman" <mpe@ellerman.id.au>,
	"Michal Hocko" <mhocko@suse.com>,
	"Mike Kravetz" <mike.kravetz@oracle.com>,
	"Paul Mackerras" <paulus@samba.org>,
	"Shuah Khan" <shuah@kernel.org>,
	"Vlastimil Babka" <vbabka@suse.cz>,
	bpf@vger.kernel.org, dri-devel@lists.freedesktop.org,
	kvm@vger.kernel.org, linux-block@vger.kernel.org,
	linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kselftest@vger.kernel.org, linux-media@vger.kernel.org,
	linux-rdma@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	netdev@vger.kernel.org, linux-mm@kvack.org,
	LKML <linux-kernel@vger.kernel.org>,
	"Maor Gottlieb" <maorg@mellanox.com>
Subject: Re: [PATCH v11 00/25] mm/gup: track dma-pinned pages: FOLL_PIN
Date: Fri, 20 Dec 2019 15:13:57 -0800	[thread overview]
Message-ID: <b70ac328-2dc0-efe3-05c2-3e040b662256@nvidia.com> (raw)
In-Reply-To: <20191220184821.GB10944@unreal>

On 12/20/19 10:48 AM, Leon Romanovsky wrote:
...
>> test_query_qp (tests.test_qp.QPTest) ... ok
>> test_rdmacm_sync_traffic (tests.test_rdmacm.CMTestCase) ... skipped 'No devices with net interface'
>>
>> ======================================================================
>> FAIL: test_query_port (tests.test_device.DeviceTest)
>> ----------------------------------------------------------------------
>> Traceback (most recent call last):
>>   File "/kernel_work/rdma-core/tests/test_device.py", line 129, in test_query_port
>>     self.verify_port_attr(port_attr)
>>   File "/kernel_work/rdma-core/tests/test_device.py", line 113, in verify_port_attr
>>     assert 'Invalid' not in d.speed_to_str(attr.active_speed)
>> AssertionError
> 
> I'm very curious how did you get this assert "d.speed_to_str" covers all
> known speeds according to the IBTA.
> 

Hi Leon,

Short answer: I can make that one pass, with a small fix the the rdma-core test
suite:

commit a1b9fb0846e1b2356d7a16f4fbdd1960cf8dcbe5 (HEAD -> fix_speed_to_str)
Author: John Hubbard <jhubbard@nvidia.com>
Date:   Fri Dec 20 15:07:47 2019 -0800

    device: fix speed_to_str(), to handle disabled links
    
    For disabled links, the raw speed token is 0. However,
    speed_to_str() doesn't have that in the list. This leads
    to an assertion when running tests (test_query_port) when
    one link is down and other link(s) are up.
    
    Fix this by returning '(Disabled/down)' for the zero speed
    case.

diff --git a/pyverbs/device.pyx b/pyverbs/device.pyx
index 33d133fd..f8b7826b 100755
--- a/pyverbs/device.pyx
+++ b/pyverbs/device.pyx
@@ -923,8 +923,8 @@ def width_to_str(width):
 
 
 def speed_to_str(speed):
-    l = {1: '2.5 Gbps', 2: '5.0 Gbps', 4: '5.0 Gbps', 8: '10.0 Gbps',
-         16: '14.0 Gbps', 32: '25.0 Gbps', 64: '50.0 Gbps'}
+    l = {0: '(Disabled/down)', 1: '2.5 Gbps', 2: '5.0 Gbps', 4: '5.0 Gbps',
+         8: '10.0 Gbps', 16: '14.0 Gbps', 32: '25.0 Gbps', 64: '50.0 Gbps'}
     try:
         return '{s} ({n})'.format(s=l[speed], n=speed)
     except KeyError:


Longer answer:
==============

It looks like this test suite assumes that every link is connected! (Probably
in most test systems, they are.) But in my setup, the ConnectX cards each have
two slots, and I only have (and only need) one cable. So one link is up, and
the other is disabled. 

This leads to the other problem, which is that if a link is disabled, the
test suite finds a "0" token for attr.active_speed. That token is not in the
approved list, and so d.speed_to_str() asserts.

With some diagnostics added, I can see it checking each link: one passes, and
the other asserts:

diff --git a/tests/test_device.py b/tests/test_device.py
index 524e0e89..7b33d7db 100644
--- a/tests/test_device.py
+++ b/tests/test_device.py
@@ -110,6 +110,12 @@ class DeviceTest(unittest.TestCase):
         assert 'Invalid' not in d.translate_mtu(attr.max_mtu)
         assert 'Invalid' not in d.translate_mtu(attr.active_mtu)
         assert 'Invalid' not in d.width_to_str(attr.active_width)
+        print("")
+        print('Diagnostics ===========================================')
+        print('phys_state:    ', d.phys_state_to_str(attr.phys_state))
+        print('active_width): ', d.width_to_str(attr.active_width))
+        print('active_speed:  ',   d.speed_to_str(attr.active_speed))
+        print('END of Diagnostics ====================================')
         assert 'Invalid' not in d.speed_to_str(attr.active_speed)
         assert 'Invalid' not in d.translate_link_layer(attr.link_layer)
         assert attr.max_msg_sz > 0x1000

         assert attr.max_msg_sz > 0x1000

...and the test run from that is:

# ./build/bin/run_tests.py --verbose tests.test_device.DeviceTest
test_dev_list (tests.test_device.DeviceTest) ... ok
test_open_dev (tests.test_device.DeviceTest) ... ok
test_query_device (tests.test_device.DeviceTest) ... ok
test_query_device_ex (tests.test_device.DeviceTest) ... ok
test_query_gid (tests.test_device.DeviceTest) ... ok
test_query_port (tests.test_device.DeviceTest) ... 
Diagnostics ===========================================
phys_state:     Link up (5)
active_width):  4X (2)
active_speed:   25.0 Gbps (32)
END of Diagnostics ====================================

Diagnostics ===========================================
phys_state:     Disabled (3)
active_width):  4X (2)
active_speed:   Invalid speed
END of Diagnostics ====================================
FAIL
test_query_port_bad_flow (tests.test_device.DeviceTest) ... ok

======================================================================
FAIL: test_query_port (tests.test_device.DeviceTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/kernel_work/rdma-core/tests/test_device.py", line 135, in test_query_port
    self.verify_port_attr(port_attr)
  File "/kernel_work/rdma-core/tests/test_device.py", line 119, in verify_port_attr
    assert 'Invalid' not in d.speed_to_str(attr.active_speed)
AssertionError

----------------------------------------------------------------------
Ran 7 tests in 0.055s

FAILED (failures=1)



thanks,
-- 
John Hubbard
NVIDIA

