Messages in this thread | | | Subject | Re: [PATCH v4 5/5] nvdimm: Schedule device registration on node local to the device | From | Alexander Duyck <> | Date | Thu, 20 Sep 2018 17:16:22 -0700 |
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On 9/20/2018 3:59 PM, Dan Williams wrote: > On Thu, Sep 20, 2018 at 3:31 PM Alexander Duyck > <alexander.h.duyck@linux.intel.com> wrote: >> >> This patch is meant to force the device registration for nvdimm devices to >> be closer to the actual device. This is achieved by using either the NUMA >> node ID of the region, or of the parent. By doing this we can have >> everything above the region based on the region, and everything below the >> region based on the nvdimm bus. >> >> One additional change I made is that we hold onto a reference to the parent >> while we are going through registration. By doing this we can guarantee we >> can complete the registration before we have the parent device removed. >> >> By guaranteeing NUMA locality I see an improvement of as high as 25% for >> per-node init of a system with 12TB of persistent memory. >> >> Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> >> --- >> drivers/nvdimm/bus.c | 19 +++++++++++++++++-- >> 1 file changed, 17 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c >> index 8aae6dcc839f..ca935296d55e 100644 >> --- a/drivers/nvdimm/bus.c >> +++ b/drivers/nvdimm/bus.c >> @@ -487,7 +487,9 @@ static void nd_async_device_register(void *d, async_cookie_t cookie) >> dev_err(dev, "%s: failed\n", __func__); >> put_device(dev); >> } >> + >> put_device(dev); >> + put_device(dev->parent); > > Good catch. The child does not pin the parent until registration, but > we need to make sure the parent isn't gone while were waiting for the > registration work to run. > > Let's break this reference count fix out into its own separate patch, > because this looks to be covering a gap that may need to be > recommended for -stable.
Okay, I guess I can do that.
> >> >> static void nd_async_device_unregister(void *d, async_cookie_t cookie) >> @@ -504,12 +506,25 @@ static void nd_async_device_unregister(void *d, async_cookie_t cookie) >> >> void __nd_device_register(struct device *dev) >> { >> + int node; >> + >> if (!dev) >> return; >> + >> dev->bus = &nvdimm_bus_type; >> + get_device(dev->parent); >> get_device(dev); >> - async_schedule_domain(nd_async_device_register, dev, >> - &nd_async_domain); >> + >> + /* >> + * For a region we can break away from the parent node, >> + * otherwise for all other devices we just inherit the node from >> + * the parent. >> + */ >> + node = is_nd_region(dev) ? to_nd_region(dev)->numa_node : >> + dev_to_node(dev->parent); > > Devices already automatically inherit the node of their parent, so I'm > not understanding why this is needed?
That doesn't happen until you call device_add, which you don't call until nd_async_device_register. All that has been called on the device up to now is device_initialize which leaves the node at NUMA_NO_NODE.
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