On Mon, Oct 07, 2024 at 06:16:06PM -0500, Ira Weiny wrote: > A git tree of this series can be found here: > > https://github.com/weiny2/linux-kernel/tree/dcd-v4-2024-10-04 > > Series info > =========== > Hi Ira, Based on current DC extent release logic, when the extent to release is in use (for example, created a dax device), no response (4803h) will be sent. Should we send a response with empty extent list instead? Fan > This series has 5 parts: > > Patch 1-3: Add %pra printk format for struct range > Patch 4: Add core range_overlaps() function > Patch 5-6: CXL clean up/prelim patches > Patch 7-26: Core DCD support > Patch 27-28: cxl_test support > > Background > ========== > > A Dynamic Capacity Device (DCD) (CXL 3.1 sec 9.13.3) is a CXL memory > device that allows memory capacity within a region to change > dynamically without the need for resetting the device, reconfiguring > HDM decoders, or reconfiguring software DAX regions. > > One of the biggest use cases for Dynamic Capacity is to allow hosts to > share memory dynamically within a data center without increasing the > per-host attached memory. > > The general flow for the addition or removal of memory is to have an > orchestrator coordinate the use of the memory. Generally there are 5 > actors in such a system, the Orchestrator, Fabric Manager, the Logical > device, the Host Kernel, and a Host User. > > Typical work flows are shown below. > > Orchestrator FM Device Host Kernel Host User > > | | | | | > |-------------- Create region ----------------------->| > | | | | | > | | | |<-- Create ---| > | | | | Region | > |<------------- Signal done --------------------------| > | | | | | > |-- Add ----->|-- Add --->|--- Add --->| | > | Capacity | Extent | Extent | | > | | | | | > | |<- Accept -|<- Accept -| | > | | Extent | Extent | | > | | | |<- Create --->| > | | | | DAX dev |-- Use memory > | | | | | | > | | | | | | > | | | |<- Release ---| <-+ > | | | | DAX dev | > | | | | | > |<------------- Signal done --------------------------| > | | | | | > |-- Remove -->|- Release->|- Release ->| | > | Capacity | Extent | Extent | | > | | | | | > | |<- Release-|<- Release -| | > | | Extent | Extent | | > | | | | | > |-- Add ----->|-- Add --->|--- Add --->| | > | Capacity | Extent | Extent | | > | | | | | > | |<- Accept -|<- Accept -| | > | | Extent | Extent | | > | | | |<- Create ----| > | | | | DAX dev |-- Use memory > | | | | | | > | | | |<- Release ---| <-+ > | | | | DAX dev | > |<------------- Signal done --------------------------| > | | | | | > |-- Remove -->|- Release->|- Release ->| | > | Capacity | Extent | Extent | | > | | | | | > | |<- Release-|<- Release -| | > | | Extent | Extent | | > | | | | | > |-- Add ----->|-- Add --->|--- Add --->| | > | Capacity | Extent | Extent | | > | | | |<- Create ----| > | | | | DAX dev |-- Use memory > | | | | | | > |-- Remove -->|- Release->|- Release ->| | | > | Capacity | Extent | Extent | | | > | | | | | | > | | | (Release Ignored) | | > | | | | | | > | | | |<- Release ---| <-+ > | | | | DAX dev | > |<------------- Signal done --------------------------| > | | | | | > | |- Release->|- Release ->| | > | | Extent | Extent | | > | | | | | > | |<- Release-|<- Release -| | > | | Extent | Extent | | > | | | |<- Destroy ---| > | | | | Region | > | | | | | > > Implementation > ============== > > The series still requires the creation of regions and DAX devices to be > closely synchronized with the Orchestrator and Fabric Manager. The host > kernel will reject extents if a region is not yet created. It also > ignores extent release if memory is in use (DAX device created). These > synchronizations are not anticipated to be an issue with real > applications. > > In order to allow for capacity to be added and removed a new concept of > a sparse DAX region is introduced. A sparse DAX region may have 0 or > more bytes of available space. The total space depends on the number > and size of the extents which have been added. > > Initially it is anticipated that users of the memory will carefully > coordinate the surfacing of additional capacity with the creation of DAX > devices which use that capacity. Therefore, the allocation of the > memory to DAX devices does not allow for specific associations between > DAX device and extent. This keeps allocations very similar to existing > DAX region behavior. > > To keep the DAX memory allocation aligned with the existing DAX devices > which do not have tags extents are not allowed to have tags. Future > support for tags is planned. > > Great care was taken to keep the extent tracking simple. Some xarray's > needed to be added but extra software objects were kept to a minimum. > > Region extents continue to be tracked as sub-devices of the DAX region. > This ensures that region destruction cleans up all extent allocations > properly. > > Some review tags were kept if a patch did not change. > > The major functionality of this series includes: > > - Getting the dynamic capacity (DC) configuration information from cxl > devices > > - Configuring the DC partitions reported by hardware > > - Enhancing the CXL and DAX regions for dynamic capacity support > a. Maintain a logical separation between hardware extents and > software managed region extents. This provides an > abstraction between the layers and should allow for > interleaving in the future > > - Get hardware extent lists for endpoint decoders upon > region creation. > > - Adjust extent/region memory available on the following events. > a. Add capacity Events > b. Release capacity events > > - Host response for add capacity > a. do not accept the extent if: > If the region does not exist > or an error occurs realizing the extent > b. If the region does exist > realize a DAX region extent with 1:1 mapping (no > interleave yet) > c. Support the event more bit by processing a list of extents > marked with the more bit together before setting up a > response. > > - Host response for remove capacity > a. If no DAX device references the extent; release the extent > b. If a reference does exist, ignore the request. > (Require FM to issue release again.) > > - Modify DAX device creation/resize to account for extents within a > sparse DAX region > > - Trace Dynamic Capacity events for debugging > > - Add cxl-test infrastructure to allow for faster unit testing > (See new ndctl branch for cxl-dcd.sh test[1]) > > - Only support 0 value extent tags > > Fan Ni's upstream of Qemu DCD was used for testing. > > Remaining work: > > 1) Allow mapping to specific extents (perhaps based on > label/tag) > 1a) devise region size reporting based on tags > 2) Interleave support > > Possible additional work depending on requirements: > > 1) Accept a new extent which extends (but overlaps) an existing > extent(s) > 2) Release extents when DAX devices are released if a release > was previously seen from the device > 3) Rework DAX device interfaces, memfd has been explored a bit > > [1] https://github.com/weiny2/ndctl/tree/dcd-region2-2024-10-01 > > --- > Major changes in v4: > - iweiny: rebase to 6.12-rc > - iweiny: Add qos data to regions > - Jonathan: Fix up shared region detection > - Jonathan/jgroves/djbw/iweiny: Ignore 0 value tags > - iweiny: Change DCD partition sysfs entries to allow for qos class and > additional parameters per partition > - Petr/Andy: s/%par/%pra/ > - Andy: Share logic between printing struct resource and struct range > - Link to v3: https://patch.msgid.link/20240816-dcd-type2-upstream-v3-0-7c9b96cba6d7@xxxxxxxxx > > --- > Ira Weiny (14): > test printk: Add very basic struct resource tests > printk: Add print format (%pra) for struct range > cxl/cdat: Use %pra for dpa range outputs > range: Add range_overlaps() > dax: Document dax dev range tuple > cxl/pci: Delay event buffer allocation > cxl/cdat: Gather DSMAS data for DCD regions > cxl/region: Refactor common create region code > cxl/events: Split event msgnum configuration from irq setup > cxl/pci: Factor out interrupt policy check > cxl/core: Return endpoint decoder information from region search > dax/bus: Factor out dev dax resize logic > tools/testing/cxl: Make event logs dynamic > tools/testing/cxl: Add DC Regions to mock mem data > > Navneet Singh (14): > cxl/mbox: Flag support for Dynamic Capacity Devices (DCD) > cxl/mem: Read dynamic capacity configuration from the device > cxl/core: Separate region mode from decoder mode > cxl/region: Add dynamic capacity decoder and region modes > cxl/hdm: Add dynamic capacity size support to endpoint decoders > cxl/mem: Expose DCD partition capabilities in sysfs > cxl/port: Add endpoint decoder DC mode support to sysfs > cxl/region: Add sparse DAX region support > cxl/mem: Configure dynamic capacity interrupts > cxl/extent: Process DCD events and realize region extents > cxl/region/extent: Expose region extent information in sysfs > dax/region: Create resources on sparse DAX regions > cxl/region: Read existing extents on region creation > cxl/mem: Trace Dynamic capacity Event Record > > Documentation/ABI/testing/sysfs-bus-cxl | 120 +++- > Documentation/core-api/printk-formats.rst | 13 + > drivers/cxl/core/Makefile | 2 +- > drivers/cxl/core/cdat.c | 52 +- > drivers/cxl/core/core.h | 33 +- > drivers/cxl/core/extent.c | 486 +++++++++++++++ > drivers/cxl/core/hdm.c | 213 ++++++- > drivers/cxl/core/mbox.c | 605 ++++++++++++++++++- > drivers/cxl/core/memdev.c | 130 +++- > drivers/cxl/core/port.c | 13 +- > drivers/cxl/core/region.c | 170 ++++-- > drivers/cxl/core/trace.h | 65 ++ > drivers/cxl/cxl.h | 122 +++- > drivers/cxl/cxlmem.h | 131 +++- > drivers/cxl/pci.c | 123 +++- > drivers/dax/bus.c | 352 +++++++++-- > drivers/dax/bus.h | 4 +- > drivers/dax/cxl.c | 72 ++- > drivers/dax/dax-private.h | 47 +- > drivers/dax/hmem/hmem.c | 2 +- > drivers/dax/pmem.c | 2 +- > fs/btrfs/ordered-data.c | 10 +- > include/acpi/actbl1.h | 2 + > include/cxl/event.h | 32 + > include/linux/range.h | 7 + > lib/test_printf.c | 70 +++ > lib/vsprintf.c | 55 +- > tools/testing/cxl/Kbuild | 3 +- > tools/testing/cxl/test/mem.c | 960 ++++++++++++++++++++++++++---- > 29 files changed, 3576 insertions(+), 320 deletions(-) > --- > base-commit: 9852d85ec9d492ebef56dc5f229416c925758edc > change-id: 20230604-dcd-type2-upstream-0cd15f6216fd > > Best regards, > -- > Ira Weiny <ira.weiny@xxxxxxxxx> > -- Fan Ni
