On 2019/9/5 15:33, Greg KH wrote: > On Thu, Sep 05, 2019 at 02:48:24PM +0800, Yunsheng Lin wrote: >> On 2019/9/5 13:57, Greg KH wrote: >>> On Thu, Sep 05, 2019 at 09:33:50AM +0800, Yunsheng Lin wrote: >>>> Currently a device does not belong to any of the numa nodes >>>> (dev->numa_node is NUMA_NO_NODE) when the FW does not provide >>>> the node id and the device has not no parent device. >>>> >>>> According to discussion in [1]: >>>> Even if a device's numa node is not set by fw, the device >>>> really does belong to a node. >>>> >>>> This patch sets the device node to node 0 in device_add() if >>>> the fw has not specified the node id and it either has no >>>> parent device, or the parent device also does not have a valid >>>> node id. >>>> >>>> There may be explicit handling out there relying on NUMA_NO_NODE, >>>> like in nvme_probe(). >>>> >>>> [1] https://lkml.org/lkml/2019/9/2/466 >>>> >>>> Signed-off-by: Yunsheng Lin <linyunsh...@huawei.com> >>>> --- >>>> drivers/base/core.c | 17 ++++++++++++++--- >>>> include/linux/numa.h | 2 ++ >>>> 2 files changed, 16 insertions(+), 3 deletions(-) >>>> >>>> diff --git a/drivers/base/core.c b/drivers/base/core.c >>>> index 1669d41..466b8ff 100644 >>>> --- a/drivers/base/core.c >>>> +++ b/drivers/base/core.c >>>> @@ -2107,9 +2107,20 @@ int device_add(struct device *dev) >>>> if (kobj) >>>> dev->kobj.parent = kobj; >>>> >>>> - /* use parent numa_node */ >>>> - if (parent && (dev_to_node(dev) == NUMA_NO_NODE)) >>>> - set_dev_node(dev, dev_to_node(parent)); >>>> + /* use parent numa_node or default node 0 */ >>>> + if (!numa_node_valid(dev_to_node(dev))) { >>>> + int nid = parent ? dev_to_node(parent) : NUMA_NO_NODE; >>> >>> Can you expand this to be a "real" if statement please? >> >> Sure. May I ask why "? :" is not appropriate here? > > Because it is a pain to read, just spell it out and make it obvious what > is happening. You write code for developers first, and the compiler > second, and in this case, either way is identical to the compiler. > >>>> + >>>> + if (numa_node_valid(nid)) { >>>> + set_dev_node(dev, nid); >>>> + } else { >>>> + if (nr_node_ids > 1U) >>>> + pr_err("device: '%s': has invalid NUMA >>>> node(%d)\n", >>>> + dev_name(dev), dev_to_node(dev)); >>> >>> dev_err() will show you the exact device properly, instead of having to >>> rely on dev_name(). >>> >>> And what is a user to do if this message happens? How do they fix this? >>> If they can not, what good is this error message? >> >> If user know about their system's topology well enough and node 0 >> is not the nearest node to the device, maybe user can readjust that by >> writing the nearest node to /sys/class/pci_bus/XXXX/device/numa_node, >> if not, then maybe user need to contact the vendor for info or updates. >> >> Maybe print error message as below: >> >> dev_err(dev, FW_BUG "has invalid NUMA node(%d). Readjust it by writing to >> sysfs numa_node or contact your vendor for updates.\n", >> dev_to_node(dev)); > > FW_BUG?
The sysfs numa_node writing interface does print FW_BUG error. Maybe it is a way of telling the user to contact the vendors, which pushing the vendors to update the FW. If FW_BUG is too much, there is FW_WARN or FW_INFO. > > Anyway, if you make this change, how many machines start reporting this > error? You should also say something like "default node of 0 now > selected" or something like that, right? Yes. > > thanks, > > greg k-h > > . >
