[driver-core PATCH v10 0/9] Add NUMA aware async_schedule calls

From: Alexander Duyck
Date: Tue Jan 22 2019 - 13:39:08 EST


This patch set provides functionality that will help to improve the
locality of the async_schedule calls used to provide deferred
initialization.

This patch set originally started out focused on just the one call to
async_schedule_domain in the nvdimm tree that was being used to defer the
device_add call however after doing some digging I realized the scope of
this was much broader than I had originally planned. As such I went
through and reworked the underlying infrastructure down to replacing the
queue_work call itself with a function of my own and opted to try and
provide a NUMA aware solution that would work for a broader audience.

In addition I have added several tweaks and/or clean-ups to the front of the
patch set. Patches 1 through 3 address a number of issues that actually were
causing the existing async_schedule calls to not show the performance that
they could due to either not scaling on a per device basis, or due to issues
that could result in a potential race. For example, patch 3 addresses the
fact that we were calling async_schedule once per driver instead of once
per device, and as a result we would have still ended up with devices
being probed on a non-local node without addressing this first.

I have also updated the kernel module used to test async driver probing so
that it can expose the original issue I was attempting to address.
It will fail on a system of asynchronous work either takes longer than it
takes to load a single device and a single driver with a device already
added. It will also fail if the NUMA node that the driver is loaded on does
not match the NUMA node the device is associated with.

RFC->v1:
Dropped nvdimm patch to submit later.
It relies on code in libnvdimm development tree.
Simplified queue_work_near to just convert node into a CPU.
Split up drivers core and PM core patches.
v1->v2:
Renamed queue_work_near to queue_work_node
Added WARN_ON_ONCE if we use queue_work_node with per-cpu workqueue
v2->v3:
Added Acked-by for queue_work_node patch
Continued rename from _near to _node to be consistent with queue_work_node
Renamed async_schedule_near_domain to async_schedule_node_domain
Renamed async_schedule_near to async_schedule_node
Added kerneldoc for new async_schedule_XXX functions
Updated patch description for patch 4 to include data on potential gains
v3->v4
Added patch to consolidate use of need_parent_lock
Make asynchronous driver probing explicit about use of drvdata
v4->v5
Added patch to move async_synchronize_full to address deadlock
Added bit async_probe to act as mutex for probe/remove calls
Added back nvdimm patch as code it relies on is now in Linus's tree
Incorporated review comments on parent & device locking consolidation
Rebased on latest linux-next
v5->v6:
Drop the "This patch" or "This change" from start of patch descriptions.
Drop unnecessary parenthesis in first patch
Use same wording for "selecting a CPU" in comments added in first patch
Added kernel documentation for async_probe member of device
Fixed up comments for async_schedule calls in patch 2
Moved code related setting async driver out of device.h and into dd.c
Added Reviewed-by for several patches
v6->v7:
Fixed typo which had kernel doc refer to "lock" when I meant "unlock"
Dropped "bool X:1" to "u8 X:1" from patch description
Added async_driver to device_private structure to store driver
Dropped unecessary code shuffle from async_probe patch
Reordered patches to move fixes up to front
Added Reviewed-by for several patches
Updated cover page and patch descriptions throughout the set
v7->v8:
Replaced async_probe value with dead, only apply dead in device_del
Dropped Reviewed-by from patch 2 due to significant changes
Added Reviewed-by for patches reviewed by Luis Chamberlain
v8->v9:
Dropped patch 1 as it was applied, shifted remaining patches by 1
Added new patch 9 that adds test framework for NUMA and sequential init
Tweaked what is now patch 1, and added Reviewed-by from Dan Williams
v9->v10:
Moved "dead" from device struct to device_private struct
Added Reviewed-by from Rafael to patch 1
Rebased on latest linux-next

---

Alexander Duyck (9):
driver core: Establish order of operations for device_add and device_del via bitflag
device core: Consolidate locking and unlocking of parent and device
driver core: Probe devices asynchronously instead of the driver
workqueue: Provide queue_work_node to queue work near a given NUMA node
async: Add support for queueing on specific NUMA node
driver core: Attach devices on CPU local to device node
PM core: Use new async_schedule_dev command
libnvdimm: Schedule device registration on node local to the device
driver core: Rewrite test_async_driver_probe to cover serialization and NUMA affinity


drivers/base/base.h | 8 +
drivers/base/bus.c | 46 +----
drivers/base/core.c | 11 +
drivers/base/dd.c | 160 +++++++++++++----
drivers/base/power/main.c | 12 +
drivers/base/test/test_async_driver_probe.c | 261 +++++++++++++++++++++------
drivers/nvdimm/bus.c | 11 +
include/linux/async.h | 82 ++++++++
include/linux/workqueue.h | 2
kernel/async.c | 53 +++--
kernel/workqueue.c | 84 +++++++++
11 files changed, 564 insertions(+), 166 deletions(-)

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