| Message ID | 20240816-dcd-type2-upstream-v3-13-7c9b96cba6d7@intel.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Delegated to: | Ira Weiny |
| Headers | show |
| Series | DCD: Add support for Dynamic Capacity Devices (DCD) | expand |
On 8/16/24 7:44 AM, ira.weiny@intel.com wrote: > From: Navneet Singh <navneet.singh@intel.com> > > Dynamic Capacity CXL regions must allow memory to be added or removed > dynamically. In addition to the quantity of memory available the > location of the memory within a DC partition is dynamic based on the > extents offered by a device. CXL DAX regions must accommodate the > sparseness of this memory in the management of DAX regions and devices. > > Introduce the concept of a sparse DAX region. Add a create_dc_region() > sysfs entry to create such regions. Special case DC capable regions to > create a 0 sized seed DAX device to maintain compatibility which > requires a default DAX device to hold a region reference. > > Indicate 0 byte available capacity until such time that capacity is > added. > > Sparse regions complicate the range mapping of dax devices. There is no > known use case for range mapping on sparse regions. Avoid the > complication by preventing range mapping of dax devices on sparse > regions. > > Interleaving is deferred for now. Add checks. > > Signed-off-by: Navneet Singh <navneet.singh@intel.com> > Co-developed-by: Ira Weiny <ira.weiny@intel.com> > Signed-off-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> > > --- > Changes: > [Fan: use single function for dc region store] > [djiang: avoid setting dev_size twice] > [djbw: Check DCD support and interleave restriction on region creation] > [iweiny: squash patch : dax/region: Prevent range mapping allocation on sparse regions] > [iwieny: remove reviews] > [iweiny: rebase to master] > [iweiny: push sysfs version to 6.12] > [iweiny: make cxled_to_mds inline] > --- > Documentation/ABI/testing/sysfs-bus-cxl | 22 ++++++++-------- > drivers/cxl/core/core.h | 12 +++++++++ > drivers/cxl/core/port.c | 1 + > drivers/cxl/core/region.c | 46 +++++++++++++++++++++++++++++++-- > drivers/dax/bus.c | 10 +++++++ > drivers/dax/bus.h | 1 + > drivers/dax/cxl.c | 16 ++++++++++-- > 7 files changed, 93 insertions(+), 15 deletions(-) > > diff --git a/Documentation/ABI/testing/sysfs-bus-cxl b/Documentation/ABI/testing/sysfs-bus-cxl > index 6227ae0ab3fc..3a5ee88e551b 100644 > --- a/Documentation/ABI/testing/sysfs-bus-cxl > +++ b/Documentation/ABI/testing/sysfs-bus-cxl > @@ -406,20 +406,20 @@ Description: > interleave_granularity). > > > -What: /sys/bus/cxl/devices/decoderX.Y/create_{pmem,ram}_region > -Date: May, 2022, January, 2023 > -KernelVersion: v6.0 (pmem), v6.3 (ram) > +What: /sys/bus/cxl/devices/decoderX.Y/create_{pmem,ram,dc}_region > +Date: May, 2022, January, 2023, August 2024 > +KernelVersion: v6.0 (pmem), v6.3 (ram), v6.12 (dc) > Contact: linux-cxl@vger.kernel.org > Description: > (RW) Write a string in the form 'regionZ' to start the process > - of defining a new persistent, or volatile memory region > - (interleave-set) within the decode range bounded by root decoder > - 'decoderX.Y'. The value written must match the current value > - returned from reading this attribute. An atomic compare exchange > - operation is done on write to assign the requested id to a > - region and allocate the region-id for the next creation attempt. > - EBUSY is returned if the region name written does not match the > - current cached value. > + of defining a new persistent, volatile, or Dynamic Capacity > + (DC) memory region (interleave-set) within the decode range > + bounded by root decoder 'decoderX.Y'. The value written must > + match the current value returned from reading this attribute. > + An atomic compare exchange operation is done on write to assign > + the requested id to a region and allocate the region-id for the > + next creation attempt. EBUSY is returned if the region name > + written does not match the current cached value. > > > What: /sys/bus/cxl/devices/decoderX.Y/delete_region > diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h > index 72a506c9dbd0..15b6cf1c19ef 100644 > --- a/drivers/cxl/core/core.h > +++ b/drivers/cxl/core/core.h > @@ -4,15 +4,27 @@ > #ifndef __CXL_CORE_H__ > #define __CXL_CORE_H__ > > +#include <cxlmem.h> > + > extern const struct device_type cxl_nvdimm_bridge_type; > extern const struct device_type cxl_nvdimm_type; > extern const struct device_type cxl_pmu_type; > > extern struct attribute_group cxl_base_attribute_group; > > +static inline struct cxl_memdev_state * > +cxled_to_mds(struct cxl_endpoint_decoder *cxled) > +{ > + struct cxl_memdev *cxlmd = cxled_to_memdev(cxled); > + struct cxl_dev_state *cxlds = cxlmd->cxlds; > + > + return container_of(cxlds, struct cxl_memdev_state, cxlds); > +} > + > #ifdef CONFIG_CXL_REGION > extern struct device_attribute dev_attr_create_pmem_region; > extern struct device_attribute dev_attr_create_ram_region; > +extern struct device_attribute dev_attr_create_dc_region; > extern struct device_attribute dev_attr_delete_region; > extern struct device_attribute dev_attr_region; > extern const struct device_type cxl_pmem_region_type; > diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c > index 222aa0aeeef7..44e1e203173d 100644 > --- a/drivers/cxl/core/port.c > +++ b/drivers/cxl/core/port.c > @@ -320,6 +320,7 @@ static struct attribute *cxl_decoder_root_attrs[] = { > &dev_attr_qos_class.attr, > SET_CXL_REGION_ATTR(create_pmem_region) > SET_CXL_REGION_ATTR(create_ram_region) > + SET_CXL_REGION_ATTR(create_dc_region) > SET_CXL_REGION_ATTR(delete_region) > NULL, > }; > diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c > index f85b26b39b2f..35c4a1f4f9bd 100644 > --- a/drivers/cxl/core/region.c > +++ b/drivers/cxl/core/region.c > @@ -496,6 +496,11 @@ static ssize_t interleave_ways_store(struct device *dev, > if (rc) > return rc; > > + if (cxlr->mode == CXL_REGION_DC && val != 1) { > + dev_err(dev, "Interleaving and DCD not supported\n"); > + return -EINVAL; > + } > + > rc = ways_to_eiw(val, &iw); > if (rc) > return rc; > @@ -2174,6 +2179,7 @@ static size_t store_targetN(struct cxl_region *cxlr, const char *buf, int pos, > if (sysfs_streq(buf, "\n")) > rc = detach_target(cxlr, pos); > else { > + struct cxl_endpoint_decoder *cxled; > struct device *dev; > > dev = bus_find_device_by_name(&cxl_bus_type, NULL, buf); > @@ -2185,8 +2191,13 @@ static size_t store_targetN(struct cxl_region *cxlr, const char *buf, int pos, > goto out; > } > > - rc = attach_target(cxlr, to_cxl_endpoint_decoder(dev), pos, > - TASK_INTERRUPTIBLE); > + cxled = to_cxl_endpoint_decoder(dev); > + if (cxlr->mode == CXL_REGION_DC && > + !cxl_dcd_supported(cxled_to_mds(cxled))) { > + dev_dbg(dev, "DCD unsupported\n"); > + return -EINVAL; > + } > + rc = attach_target(cxlr, cxled, pos, TASK_INTERRUPTIBLE); > out: > put_device(dev); > } > @@ -2534,6 +2545,7 @@ static struct cxl_region *__create_region(struct cxl_root_decoder *cxlrd, > switch (mode) { > case CXL_REGION_RAM: > case CXL_REGION_PMEM: > + case CXL_REGION_DC: > break; > default: > dev_err(&cxlrd->cxlsd.cxld.dev, "unsupported mode %s\n", > @@ -2587,6 +2599,20 @@ static ssize_t create_ram_region_store(struct device *dev, > } > DEVICE_ATTR_RW(create_ram_region); > > +static ssize_t create_dc_region_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + return __create_region_show(to_cxl_root_decoder(dev), buf); > +} > + > +static ssize_t create_dc_region_store(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t len) > +{ > + return create_region_store(dev, buf, len, CXL_REGION_DC); > +} > +DEVICE_ATTR_RW(create_dc_region); > + > static ssize_t region_show(struct device *dev, struct device_attribute *attr, > char *buf) > { > @@ -3168,6 +3194,11 @@ static int devm_cxl_add_dax_region(struct cxl_region *cxlr) > struct device *dev; > int rc; > > + if (cxlr->mode == CXL_REGION_DC && cxlr->params.interleave_ways != 1) { > + dev_err(&cxlr->dev, "Interleaving DC not supported\n"); > + return -EINVAL; > + } > + > cxlr_dax = cxl_dax_region_alloc(cxlr); > if (IS_ERR(cxlr_dax)) > return PTR_ERR(cxlr_dax); > @@ -3260,6 +3291,16 @@ static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd, > return ERR_PTR(-EINVAL); > > mode = cxl_decoder_to_region_mode(cxled->mode); > + if (mode == CXL_REGION_DC) { > + if (!cxl_dcd_supported(cxled_to_mds(cxled))) { > + dev_err(&cxled->cxld.dev, "DCD unsupported\n"); > + return ERR_PTR(-EINVAL); > + } > + if (cxled->cxld.interleave_ways != 1) { > + dev_err(&cxled->cxld.dev, "Interleaving and DCD not supported\n"); > + return ERR_PTR(-EINVAL); > + } > + } > do { > cxlr = __create_region(cxlrd, mode, > atomic_read(&cxlrd->region_id)); > @@ -3467,6 +3508,7 @@ static int cxl_region_probe(struct device *dev) > case CXL_REGION_PMEM: > return devm_cxl_add_pmem_region(cxlr); > case CXL_REGION_RAM: > + case CXL_REGION_DC: > /* > * The region can not be manged by CXL if any portion of > * it is already online as 'System RAM' > diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c > index fde29e0ad68b..d8cb5195a227 100644 > --- a/drivers/dax/bus.c > +++ b/drivers/dax/bus.c > @@ -178,6 +178,11 @@ static bool is_static(struct dax_region *dax_region) > return (dax_region->res.flags & IORESOURCE_DAX_STATIC) != 0; > } > > +static bool is_sparse(struct dax_region *dax_region) > +{ > + return (dax_region->res.flags & IORESOURCE_DAX_SPARSE_CAP) != 0; > +} > + > bool static_dev_dax(struct dev_dax *dev_dax) > { > return is_static(dev_dax->region); > @@ -301,6 +306,9 @@ static unsigned long long dax_region_avail_size(struct dax_region *dax_region) > > lockdep_assert_held(&dax_region_rwsem); > > + if (is_sparse(dax_region)) > + return 0; > + > for_each_dax_region_resource(dax_region, res) > size -= resource_size(res); > return size; > @@ -1373,6 +1381,8 @@ static umode_t dev_dax_visible(struct kobject *kobj, struct attribute *a, int n) > return 0; > if (a == &dev_attr_mapping.attr && is_static(dax_region)) > return 0; > + if (a == &dev_attr_mapping.attr && is_sparse(dax_region)) > + return 0; > if ((a == &dev_attr_align.attr || > a == &dev_attr_size.attr) && is_static(dax_region)) > return 0444; > diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h > index cbbf64443098..783bfeef42cc 100644 > --- a/drivers/dax/bus.h > +++ b/drivers/dax/bus.h > @@ -13,6 +13,7 @@ struct dax_region; > /* dax bus specific ioresource flags */ > #define IORESOURCE_DAX_STATIC BIT(0) > #define IORESOURCE_DAX_KMEM BIT(1) > +#define IORESOURCE_DAX_SPARSE_CAP BIT(2) > > struct dax_region *alloc_dax_region(struct device *parent, int region_id, > struct range *range, int target_node, unsigned int align, > diff --git a/drivers/dax/cxl.c b/drivers/dax/cxl.c > index 9b29e732b39a..367e86b1c22a 100644 > --- a/drivers/dax/cxl.c > +++ b/drivers/dax/cxl.c > @@ -13,19 +13,31 @@ static int cxl_dax_region_probe(struct device *dev) > struct cxl_region *cxlr = cxlr_dax->cxlr; > struct dax_region *dax_region; > struct dev_dax_data data; > + resource_size_t dev_size; > + unsigned long flags; > > if (nid == NUMA_NO_NODE) > nid = memory_add_physaddr_to_nid(cxlr_dax->hpa_range.start); > > + flags = IORESOURCE_DAX_KMEM; > + if (cxlr->mode == CXL_REGION_DC) > + flags |= IORESOURCE_DAX_SPARSE_CAP; > + > dax_region = alloc_dax_region(dev, cxlr->id, &cxlr_dax->hpa_range, nid, > - PMD_SIZE, IORESOURCE_DAX_KMEM); > + PMD_SIZE, flags); > if (!dax_region) > return -ENOMEM; > > + if (cxlr->mode == CXL_REGION_DC) > + /* Add empty seed dax device */ > + dev_size = 0; > + else > + dev_size = range_len(&cxlr_dax->hpa_range); > + > data = (struct dev_dax_data) { > .dax_region = dax_region, > .id = -1, > - .size = range_len(&cxlr_dax->hpa_range), > + .size = dev_size, > .memmap_on_memory = true, > }; > >
On Fri, Aug 16, 2024 at 09:44:21AM -0500, ira.weiny@intel.com wrote: > From: Navneet Singh <navneet.singh@intel.com> > > Dynamic Capacity CXL regions must allow memory to be added or removed > dynamically. In addition to the quantity of memory available the > location of the memory within a DC partition is dynamic based on the > extents offered by a device. CXL DAX regions must accommodate the > sparseness of this memory in the management of DAX regions and devices. > > Introduce the concept of a sparse DAX region. Add a create_dc_region() > sysfs entry to create such regions. Special case DC capable regions to > create a 0 sized seed DAX device to maintain compatibility which > requires a default DAX device to hold a region reference. > > Indicate 0 byte available capacity until such time that capacity is > added. > > Sparse regions complicate the range mapping of dax devices. There is no > known use case for range mapping on sparse regions. Avoid the > complication by preventing range mapping of dax devices on sparse > regions. > > Interleaving is deferred for now. Add checks. > > Signed-off-by: Navneet Singh <navneet.singh@intel.com> > Co-developed-by: Ira Weiny <ira.weiny@intel.com> > Signed-off-by: Ira Weiny <ira.weiny@intel.com> > > --- > Changes: > [Fan: use single function for dc region store] > [djiang: avoid setting dev_size twice] > [djbw: Check DCD support and interleave restriction on region creation] > [iweiny: squash patch : dax/region: Prevent range mapping allocation on sparse regions] > [iwieny: remove reviews] > [iweiny: rebase to master] > [iweiny: push sysfs version to 6.12] > [iweiny: make cxled_to_mds inline] > --- > Documentation/ABI/testing/sysfs-bus-cxl | 22 ++++++++-------- > drivers/cxl/core/core.h | 12 +++++++++ > drivers/cxl/core/port.c | 1 + > drivers/cxl/core/region.c | 46 +++++++++++++++++++++++++++++++-- > drivers/dax/bus.c | 10 +++++++ > drivers/dax/bus.h | 1 + > drivers/dax/cxl.c | 16 ++++++++++-- > 7 files changed, 93 insertions(+), 15 deletions(-) > > diff --git a/Documentation/ABI/testing/sysfs-bus-cxl b/Documentation/ABI/testing/sysfs-bus-cxl > index 6227ae0ab3fc..3a5ee88e551b 100644 > --- a/Documentation/ABI/testing/sysfs-bus-cxl > +++ b/Documentation/ABI/testing/sysfs-bus-cxl > @@ -406,20 +406,20 @@ Description: > interleave_granularity). > > > -What: /sys/bus/cxl/devices/decoderX.Y/create_{pmem,ram}_region > -Date: May, 2022, January, 2023 > -KernelVersion: v6.0 (pmem), v6.3 (ram) > +What: /sys/bus/cxl/devices/decoderX.Y/create_{pmem,ram,dc}_region > +Date: May, 2022, January, 2023, August 2024 > +KernelVersion: v6.0 (pmem), v6.3 (ram), v6.12 (dc) > Contact: linux-cxl@vger.kernel.org > Description: > (RW) Write a string in the form 'regionZ' to start the process > - of defining a new persistent, or volatile memory region > - (interleave-set) within the decode range bounded by root decoder > - 'decoderX.Y'. The value written must match the current value > - returned from reading this attribute. An atomic compare exchange > - operation is done on write to assign the requested id to a > - region and allocate the region-id for the next creation attempt. > - EBUSY is returned if the region name written does not match the > - current cached value. > + of defining a new persistent, volatile, or Dynamic Capacity > + (DC) memory region (interleave-set) within the decode range > + bounded by root decoder 'decoderX.Y'. The value written must > + match the current value returned from reading this attribute. > + An atomic compare exchange operation is done on write to assign > + the requested id to a region and allocate the region-id for the > + next creation attempt. EBUSY is returned if the region name > + written does not match the current cached value. > > > What: /sys/bus/cxl/devices/decoderX.Y/delete_region > diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h > index 72a506c9dbd0..15b6cf1c19ef 100644 > --- a/drivers/cxl/core/core.h > +++ b/drivers/cxl/core/core.h > @@ -4,15 +4,27 @@ > #ifndef __CXL_CORE_H__ > #define __CXL_CORE_H__ > > +#include <cxlmem.h> > + > extern const struct device_type cxl_nvdimm_bridge_type; > extern const struct device_type cxl_nvdimm_type; > extern const struct device_type cxl_pmu_type; > > extern struct attribute_group cxl_base_attribute_group; > > +static inline struct cxl_memdev_state * > +cxled_to_mds(struct cxl_endpoint_decoder *cxled) > +{ > + struct cxl_memdev *cxlmd = cxled_to_memdev(cxled); > + struct cxl_dev_state *cxlds = cxlmd->cxlds; > + > + return container_of(cxlds, struct cxl_memdev_state, cxlds); > +} > + > #ifdef CONFIG_CXL_REGION > extern struct device_attribute dev_attr_create_pmem_region; > extern struct device_attribute dev_attr_create_ram_region; > +extern struct device_attribute dev_attr_create_dc_region; > extern struct device_attribute dev_attr_delete_region; > extern struct device_attribute dev_attr_region; > extern const struct device_type cxl_pmem_region_type; > diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c > index 222aa0aeeef7..44e1e203173d 100644 > --- a/drivers/cxl/core/port.c > +++ b/drivers/cxl/core/port.c > @@ -320,6 +320,7 @@ static struct attribute *cxl_decoder_root_attrs[] = { > &dev_attr_qos_class.attr, > SET_CXL_REGION_ATTR(create_pmem_region) > SET_CXL_REGION_ATTR(create_ram_region) > + SET_CXL_REGION_ATTR(create_dc_region) > SET_CXL_REGION_ATTR(delete_region) > NULL, > }; > diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c > index f85b26b39b2f..35c4a1f4f9bd 100644 > --- a/drivers/cxl/core/region.c > +++ b/drivers/cxl/core/region.c > @@ -496,6 +496,11 @@ static ssize_t interleave_ways_store(struct device *dev, > if (rc) > return rc; > > + if (cxlr->mode == CXL_REGION_DC && val != 1) { > + dev_err(dev, "Interleaving and DCD not supported\n"); Is there a typo here? Maybe "Interleaving a DCD not supported"? > + return -EINVAL; > + } > + > rc = ways_to_eiw(val, &iw); > if (rc) > return rc; > @@ -2174,6 +2179,7 @@ static size_t store_targetN(struct cxl_region *cxlr, const char *buf, int pos, > if (sysfs_streq(buf, "\n")) > rc = detach_target(cxlr, pos); > else { > + struct cxl_endpoint_decoder *cxled; > struct device *dev; > > dev = bus_find_device_by_name(&cxl_bus_type, NULL, buf); > @@ -2185,8 +2191,13 @@ static size_t store_targetN(struct cxl_region *cxlr, const char *buf, int pos, > goto out; > } > > - rc = attach_target(cxlr, to_cxl_endpoint_decoder(dev), pos, > - TASK_INTERRUPTIBLE); > + cxled = to_cxl_endpoint_decoder(dev); > + if (cxlr->mode == CXL_REGION_DC && > + !cxl_dcd_supported(cxled_to_mds(cxled))) { > + dev_dbg(dev, "DCD unsupported\n"); > + return -EINVAL; > + } > + rc = attach_target(cxlr, cxled, pos, TASK_INTERRUPTIBLE); > out: > put_device(dev); > } > @@ -2534,6 +2545,7 @@ static struct cxl_region *__create_region(struct cxl_root_decoder *cxlrd, > switch (mode) { > case CXL_REGION_RAM: > case CXL_REGION_PMEM: > + case CXL_REGION_DC: > break; > default: > dev_err(&cxlrd->cxlsd.cxld.dev, "unsupported mode %s\n", > @@ -2587,6 +2599,20 @@ static ssize_t create_ram_region_store(struct device *dev, > } > DEVICE_ATTR_RW(create_ram_region); > > +static ssize_t create_dc_region_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + return __create_region_show(to_cxl_root_decoder(dev), buf); > +} > + > +static ssize_t create_dc_region_store(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t len) > +{ > + return create_region_store(dev, buf, len, CXL_REGION_DC); > +} > +DEVICE_ATTR_RW(create_dc_region); > + > static ssize_t region_show(struct device *dev, struct device_attribute *attr, > char *buf) > { > @@ -3168,6 +3194,11 @@ static int devm_cxl_add_dax_region(struct cxl_region *cxlr) > struct device *dev; > int rc; > > + if (cxlr->mode == CXL_REGION_DC && cxlr->params.interleave_ways != 1) { > + dev_err(&cxlr->dev, "Interleaving DC not supported\n"); > + return -EINVAL; > + } > + > cxlr_dax = cxl_dax_region_alloc(cxlr); > if (IS_ERR(cxlr_dax)) > return PTR_ERR(cxlr_dax); > @@ -3260,6 +3291,16 @@ static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd, > return ERR_PTR(-EINVAL); > > mode = cxl_decoder_to_region_mode(cxled->mode); > + if (mode == CXL_REGION_DC) { > + if (!cxl_dcd_supported(cxled_to_mds(cxled))) { > + dev_err(&cxled->cxld.dev, "DCD unsupported\n"); > + return ERR_PTR(-EINVAL); > + } > + if (cxled->cxld.interleave_ways != 1) { > + dev_err(&cxled->cxld.dev, "Interleaving and DCD not supported\n"); If it goes here, it means DCD is upported, but interleaving is not, so the message here may also need change. Fan > + return ERR_PTR(-EINVAL); > + } > + } > do { > cxlr = __create_region(cxlrd, mode, > atomic_read(&cxlrd->region_id)); > @@ -3467,6 +3508,7 @@ static int cxl_region_probe(struct device *dev) > case CXL_REGION_PMEM: > return devm_cxl_add_pmem_region(cxlr); > case CXL_REGION_RAM: > + case CXL_REGION_DC: > /* > * The region can not be manged by CXL if any portion of > * it is already online as 'System RAM' > diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c > index fde29e0ad68b..d8cb5195a227 100644 > --- a/drivers/dax/bus.c > +++ b/drivers/dax/bus.c > @@ -178,6 +178,11 @@ static bool is_static(struct dax_region *dax_region) > return (dax_region->res.flags & IORESOURCE_DAX_STATIC) != 0; > } > > +static bool is_sparse(struct dax_region *dax_region) > +{ > + return (dax_region->res.flags & IORESOURCE_DAX_SPARSE_CAP) != 0; > +} > + > bool static_dev_dax(struct dev_dax *dev_dax) > { > return is_static(dev_dax->region); > @@ -301,6 +306,9 @@ static unsigned long long dax_region_avail_size(struct dax_region *dax_region) > > lockdep_assert_held(&dax_region_rwsem); > > + if (is_sparse(dax_region)) > + return 0; > + > for_each_dax_region_resource(dax_region, res) > size -= resource_size(res); > return size; > @@ -1373,6 +1381,8 @@ static umode_t dev_dax_visible(struct kobject *kobj, struct attribute *a, int n) > return 0; > if (a == &dev_attr_mapping.attr && is_static(dax_region)) > return 0; > + if (a == &dev_attr_mapping.attr && is_sparse(dax_region)) > + return 0; > if ((a == &dev_attr_align.attr || > a == &dev_attr_size.attr) && is_static(dax_region)) > return 0444; > diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h > index cbbf64443098..783bfeef42cc 100644 > --- a/drivers/dax/bus.h > +++ b/drivers/dax/bus.h > @@ -13,6 +13,7 @@ struct dax_region; > /* dax bus specific ioresource flags */ > #define IORESOURCE_DAX_STATIC BIT(0) > #define IORESOURCE_DAX_KMEM BIT(1) > +#define IORESOURCE_DAX_SPARSE_CAP BIT(2) > > struct dax_region *alloc_dax_region(struct device *parent, int region_id, > struct range *range, int target_node, unsigned int align, > diff --git a/drivers/dax/cxl.c b/drivers/dax/cxl.c > index 9b29e732b39a..367e86b1c22a 100644 > --- a/drivers/dax/cxl.c > +++ b/drivers/dax/cxl.c > @@ -13,19 +13,31 @@ static int cxl_dax_region_probe(struct device *dev) > struct cxl_region *cxlr = cxlr_dax->cxlr; > struct dax_region *dax_region; > struct dev_dax_data data; > + resource_size_t dev_size; > + unsigned long flags; > > if (nid == NUMA_NO_NODE) > nid = memory_add_physaddr_to_nid(cxlr_dax->hpa_range.start); > > + flags = IORESOURCE_DAX_KMEM; > + if (cxlr->mode == CXL_REGION_DC) > + flags |= IORESOURCE_DAX_SPARSE_CAP; > + > dax_region = alloc_dax_region(dev, cxlr->id, &cxlr_dax->hpa_range, nid, > - PMD_SIZE, IORESOURCE_DAX_KMEM); > + PMD_SIZE, flags); > if (!dax_region) > return -ENOMEM; > > + if (cxlr->mode == CXL_REGION_DC) > + /* Add empty seed dax device */ > + dev_size = 0; > + else > + dev_size = range_len(&cxlr_dax->hpa_range); > + > data = (struct dev_dax_data) { > .dax_region = dax_region, > .id = -1, > - .size = range_len(&cxlr_dax->hpa_range), > + .size = dev_size, > .memmap_on_memory = true, > }; > > > -- > 2.45.2 >
On Fri, 16 Aug 2024 09:44:21 -0500 ira.weiny@intel.com wrote: > From: Navneet Singh <navneet.singh@intel.com> > > Dynamic Capacity CXL regions must allow memory to be added or removed > dynamically. In addition to the quantity of memory available the > location of the memory within a DC partition is dynamic based on the > extents offered by a device. CXL DAX regions must accommodate the > sparseness of this memory in the management of DAX regions and devices. > > Introduce the concept of a sparse DAX region. Add a create_dc_region() > sysfs entry to create such regions. Special case DC capable regions to > create a 0 sized seed DAX device to maintain compatibility which > requires a default DAX device to hold a region reference. > > Indicate 0 byte available capacity until such time that capacity is > added. > > Sparse regions complicate the range mapping of dax devices. There is no > known use case for range mapping on sparse regions. Avoid the > complication by preventing range mapping of dax devices on sparse > regions. > > Interleaving is deferred for now. Add checks. > > Signed-off-by: Navneet Singh <navneet.singh@intel.com> > Co-developed-by: Ira Weiny <ira.weiny@intel.com> > Signed-off-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
On 8/16/2024 10:44 PM, ira.weiny@intel.com wrote: > From: Navneet Singh <navneet.singh@intel.com> > > Dynamic Capacity CXL regions must allow memory to be added or removed > dynamically. In addition to the quantity of memory available the > location of the memory within a DC partition is dynamic based on the > extents offered by a device. CXL DAX regions must accommodate the > sparseness of this memory in the management of DAX regions and devices. > > Introduce the concept of a sparse DAX region. Add a create_dc_region() > sysfs entry to create such regions. Special case DC capable regions to > create a 0 sized seed DAX device to maintain compatibility which > requires a default DAX device to hold a region reference. > > Indicate 0 byte available capacity until such time that capacity is > added. > > Sparse regions complicate the range mapping of dax devices. There is no > known use case for range mapping on sparse regions. Avoid the > complication by preventing range mapping of dax devices on sparse > regions. > > Interleaving is deferred for now. Add checks. > > Signed-off-by: Navneet Singh <navneet.singh@intel.com> > Co-developed-by: Ira Weiny <ira.weiny@intel.com> > Signed-off-by: Ira Weiny <ira.weiny@intel.com> > > --- > Changes: > [Fan: use single function for dc region store] > [djiang: avoid setting dev_size twice] > [djbw: Check DCD support and interleave restriction on region creation] > [iweiny: squash patch : dax/region: Prevent range mapping allocation on sparse regions] > [iwieny: remove reviews] > [iweiny: rebase to master] > [iweiny: push sysfs version to 6.12] > [iweiny: make cxled_to_mds inline] > --- > Documentation/ABI/testing/sysfs-bus-cxl | 22 ++++++++-------- > drivers/cxl/core/core.h | 12 +++++++++ > drivers/cxl/core/port.c | 1 + > drivers/cxl/core/region.c | 46 +++++++++++++++++++++++++++++++-- > drivers/dax/bus.c | 10 +++++++ > drivers/dax/bus.h | 1 + > drivers/dax/cxl.c | 16 ++++++++++-- > 7 files changed, 93 insertions(+), 15 deletions(-) > [...] > @@ -2185,8 +2191,13 @@ static size_t store_targetN(struct cxl_region *cxlr, const char *buf, int pos, > goto out; > } > > - rc = attach_target(cxlr, to_cxl_endpoint_decoder(dev), pos, > - TASK_INTERRUPTIBLE); > + cxled = to_cxl_endpoint_decoder(dev); > + if (cxlr->mode == CXL_REGION_DC && > + !cxl_dcd_supported(cxled_to_mds(cxled))) { > + dev_dbg(dev, "DCD unsupported\n"); > + return -EINVAL; need a 'goto out' here to dereference the device? > + } > + rc = attach_target(cxlr, cxled, pos, TASK_INTERRUPTIBLE); > out: > put_device(dev); > } > @@ -2534,6 +2545,7 @@ static struct cxl_region *__create_region(struct cxl_root_decoder *cxlrd, > switch (mode) { > case CXL_REGION_RAM: > case CXL_REGION_PMEM: > + case CXL_REGION_DC: > break; > default: > dev_err(&cxlrd->cxlsd.cxld.dev, "unsupported mode %s\n", > @@ -2587,6 +2599,20 @@ static ssize_t create_ram_region_store(struct device *dev, > } > DEVICE_ATTR_RW(create_ram_region); > > +static ssize_t create_dc_region_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + return __create_region_show(to_cxl_root_decoder(dev), buf); > +} > + > +static ssize_t create_dc_region_store(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t len) > +{ > + return create_region_store(dev, buf, len, CXL_REGION_DC); > +} > +DEVICE_ATTR_RW(create_dc_region); > + > static ssize_t region_show(struct device *dev, struct device_attribute *attr, > char *buf) > { > @@ -3168,6 +3194,11 @@ static int devm_cxl_add_dax_region(struct cxl_region *cxlr) > struct device *dev; > int rc; > > + if (cxlr->mode == CXL_REGION_DC && cxlr->params.interleave_ways != 1) { > + dev_err(&cxlr->dev, "Interleaving DC not supported\n"); > + return -EINVAL; > + } > + > cxlr_dax = cxl_dax_region_alloc(cxlr); > if (IS_ERR(cxlr_dax)) > return PTR_ERR(cxlr_dax); > @@ -3260,6 +3291,16 @@ static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd, > return ERR_PTR(-EINVAL); > > mode = cxl_decoder_to_region_mode(cxled->mode); > + if (mode == CXL_REGION_DC) { > + if (!cxl_dcd_supported(cxled_to_mds(cxled))) { > + dev_err(&cxled->cxld.dev, "DCD unsupported\n"); > + return ERR_PTR(-EINVAL); > + } > + if (cxled->cxld.interleave_ways != 1) { > + dev_err(&cxled->cxld.dev, "Interleaving and DCD not supported\n"); > + return ERR_PTR(-EINVAL); > + } > + } > do { > cxlr = __create_region(cxlrd, mode, > atomic_read(&cxlrd->region_id)); > @@ -3467,6 +3508,7 @@ static int cxl_region_probe(struct device *dev) > case CXL_REGION_PMEM: > return devm_cxl_add_pmem_region(cxlr); > case CXL_REGION_RAM: > + case CXL_REGION_DC: > /* > * The region can not be manged by CXL if any portion of > * it is already online as 'System RAM' > diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c > index fde29e0ad68b..d8cb5195a227 100644 > --- a/drivers/dax/bus.c > +++ b/drivers/dax/bus.c > @@ -178,6 +178,11 @@ static bool is_static(struct dax_region *dax_region) > return (dax_region->res.flags & IORESOURCE_DAX_STATIC) != 0; > } > > +static bool is_sparse(struct dax_region *dax_region) > +{ > + return (dax_region->res.flags & IORESOURCE_DAX_SPARSE_CAP) != 0; > +} > + > bool static_dev_dax(struct dev_dax *dev_dax) > { > return is_static(dev_dax->region); > @@ -301,6 +306,9 @@ static unsigned long long dax_region_avail_size(struct dax_region *dax_region) > > lockdep_assert_held(&dax_region_rwsem); > > + if (is_sparse(dax_region)) > + return 0; > + > for_each_dax_region_resource(dax_region, res) > size -= resource_size(res); > return size; > @@ -1373,6 +1381,8 @@ static umode_t dev_dax_visible(struct kobject *kobj, struct attribute *a, int n) > return 0; > if (a == &dev_attr_mapping.attr && is_static(dax_region)) > return 0; > + if (a == &dev_attr_mapping.attr && is_sparse(dax_region)) > + return 0; > if ((a == &dev_attr_align.attr || > a == &dev_attr_size.attr) && is_static(dax_region)) > return 0444; > diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h > index cbbf64443098..783bfeef42cc 100644 > --- a/drivers/dax/bus.h > +++ b/drivers/dax/bus.h > @@ -13,6 +13,7 @@ struct dax_region; > /* dax bus specific ioresource flags */ > #define IORESOURCE_DAX_STATIC BIT(0) > #define IORESOURCE_DAX_KMEM BIT(1) > +#define IORESOURCE_DAX_SPARSE_CAP BIT(2) > > struct dax_region *alloc_dax_region(struct device *parent, int region_id, > struct range *range, int target_node, unsigned int align, > diff --git a/drivers/dax/cxl.c b/drivers/dax/cxl.c > index 9b29e732b39a..367e86b1c22a 100644 > --- a/drivers/dax/cxl.c > +++ b/drivers/dax/cxl.c > @@ -13,19 +13,31 @@ static int cxl_dax_region_probe(struct device *dev) > struct cxl_region *cxlr = cxlr_dax->cxlr; > struct dax_region *dax_region; > struct dev_dax_data data; > + resource_size_t dev_size; > + unsigned long flags; > > if (nid == NUMA_NO_NODE) > nid = memory_add_physaddr_to_nid(cxlr_dax->hpa_range.start); > > + flags = IORESOURCE_DAX_KMEM; > + if (cxlr->mode == CXL_REGION_DC) > + flags |= IORESOURCE_DAX_SPARSE_CAP; > + > dax_region = alloc_dax_region(dev, cxlr->id, &cxlr_dax->hpa_range, nid, > - PMD_SIZE, IORESOURCE_DAX_KMEM); > + PMD_SIZE, flags); > if (!dax_region) > return -ENOMEM; > > + if (cxlr->mode == CXL_REGION_DC) > + /* Add empty seed dax device */ > + dev_size = 0; > + else > + dev_size = range_len(&cxlr_dax->hpa_range); > + > data = (struct dev_dax_data) { > .dax_region = dax_region, > .id = -1, > - .size = range_len(&cxlr_dax->hpa_range), > + .size = dev_size, > .memmap_on_memory = true, > }; > >
diff --git a/Documentation/ABI/testing/sysfs-bus-cxl b/Documentation/ABI/testing/sysfs-bus-cxl index 6227ae0ab3fc..3a5ee88e551b 100644 --- a/Documentation/ABI/testing/sysfs-bus-cxl +++ b/Documentation/ABI/testing/sysfs-bus-cxl @@ -406,20 +406,20 @@ Description: interleave_granularity). -What: /sys/bus/cxl/devices/decoderX.Y/create_{pmem,ram}_region -Date: May, 2022, January, 2023 -KernelVersion: v6.0 (pmem), v6.3 (ram) +What: /sys/bus/cxl/devices/decoderX.Y/create_{pmem,ram,dc}_region +Date: May, 2022, January, 2023, August 2024 +KernelVersion: v6.0 (pmem), v6.3 (ram), v6.12 (dc) Contact: linux-cxl@vger.kernel.org Description: (RW) Write a string in the form 'regionZ' to start the process - of defining a new persistent, or volatile memory region - (interleave-set) within the decode range bounded by root decoder - 'decoderX.Y'. The value written must match the current value - returned from reading this attribute. An atomic compare exchange - operation is done on write to assign the requested id to a - region and allocate the region-id for the next creation attempt. - EBUSY is returned if the region name written does not match the - current cached value. + of defining a new persistent, volatile, or Dynamic Capacity + (DC) memory region (interleave-set) within the decode range + bounded by root decoder 'decoderX.Y'. The value written must + match the current value returned from reading this attribute. + An atomic compare exchange operation is done on write to assign + the requested id to a region and allocate the region-id for the + next creation attempt. EBUSY is returned if the region name + written does not match the current cached value. What: /sys/bus/cxl/devices/decoderX.Y/delete_region diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h index 72a506c9dbd0..15b6cf1c19ef 100644 --- a/drivers/cxl/core/core.h +++ b/drivers/cxl/core/core.h @@ -4,15 +4,27 @@ #ifndef __CXL_CORE_H__ #define __CXL_CORE_H__ +#include <cxlmem.h> + extern const struct device_type cxl_nvdimm_bridge_type; extern const struct device_type cxl_nvdimm_type; extern const struct device_type cxl_pmu_type; extern struct attribute_group cxl_base_attribute_group; +static inline struct cxl_memdev_state * +cxled_to_mds(struct cxl_endpoint_decoder *cxled) +{ + struct cxl_memdev *cxlmd = cxled_to_memdev(cxled); + struct cxl_dev_state *cxlds = cxlmd->cxlds; + + return container_of(cxlds, struct cxl_memdev_state, cxlds); +} + #ifdef CONFIG_CXL_REGION extern struct device_attribute dev_attr_create_pmem_region; extern struct device_attribute dev_attr_create_ram_region; +extern struct device_attribute dev_attr_create_dc_region; extern struct device_attribute dev_attr_delete_region; extern struct device_attribute dev_attr_region; extern const struct device_type cxl_pmem_region_type; diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c index 222aa0aeeef7..44e1e203173d 100644 --- a/drivers/cxl/core/port.c +++ b/drivers/cxl/core/port.c @@ -320,6 +320,7 @@ static struct attribute *cxl_decoder_root_attrs[] = { &dev_attr_qos_class.attr, SET_CXL_REGION_ATTR(create_pmem_region) SET_CXL_REGION_ATTR(create_ram_region) + SET_CXL_REGION_ATTR(create_dc_region) SET_CXL_REGION_ATTR(delete_region) NULL, }; diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index f85b26b39b2f..35c4a1f4f9bd 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -496,6 +496,11 @@ static ssize_t interleave_ways_store(struct device *dev, if (rc) return rc; + if (cxlr->mode == CXL_REGION_DC && val != 1) { + dev_err(dev, "Interleaving and DCD not supported\n"); + return -EINVAL; + } + rc = ways_to_eiw(val, &iw); if (rc) return rc; @@ -2174,6 +2179,7 @@ static size_t store_targetN(struct cxl_region *cxlr, const char *buf, int pos, if (sysfs_streq(buf, "\n")) rc = detach_target(cxlr, pos); else { + struct cxl_endpoint_decoder *cxled; struct device *dev; dev = bus_find_device_by_name(&cxl_bus_type, NULL, buf); @@ -2185,8 +2191,13 @@ static size_t store_targetN(struct cxl_region *cxlr, const char *buf, int pos, goto out; } - rc = attach_target(cxlr, to_cxl_endpoint_decoder(dev), pos, - TASK_INTERRUPTIBLE); + cxled = to_cxl_endpoint_decoder(dev); + if (cxlr->mode == CXL_REGION_DC && + !cxl_dcd_supported(cxled_to_mds(cxled))) { + dev_dbg(dev, "DCD unsupported\n"); + return -EINVAL; + } + rc = attach_target(cxlr, cxled, pos, TASK_INTERRUPTIBLE); out: put_device(dev); } @@ -2534,6 +2545,7 @@ static struct cxl_region *__create_region(struct cxl_root_decoder *cxlrd, switch (mode) { case CXL_REGION_RAM: case CXL_REGION_PMEM: + case CXL_REGION_DC: break; default: dev_err(&cxlrd->cxlsd.cxld.dev, "unsupported mode %s\n", @@ -2587,6 +2599,20 @@ static ssize_t create_ram_region_store(struct device *dev, } DEVICE_ATTR_RW(create_ram_region); +static ssize_t create_dc_region_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return __create_region_show(to_cxl_root_decoder(dev), buf); +} + +static ssize_t create_dc_region_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t len) +{ + return create_region_store(dev, buf, len, CXL_REGION_DC); +} +DEVICE_ATTR_RW(create_dc_region); + static ssize_t region_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -3168,6 +3194,11 @@ static int devm_cxl_add_dax_region(struct cxl_region *cxlr) struct device *dev; int rc; + if (cxlr->mode == CXL_REGION_DC && cxlr->params.interleave_ways != 1) { + dev_err(&cxlr->dev, "Interleaving DC not supported\n"); + return -EINVAL; + } + cxlr_dax = cxl_dax_region_alloc(cxlr); if (IS_ERR(cxlr_dax)) return PTR_ERR(cxlr_dax); @@ -3260,6 +3291,16 @@ static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd, return ERR_PTR(-EINVAL); mode = cxl_decoder_to_region_mode(cxled->mode); + if (mode == CXL_REGION_DC) { + if (!cxl_dcd_supported(cxled_to_mds(cxled))) { + dev_err(&cxled->cxld.dev, "DCD unsupported\n"); + return ERR_PTR(-EINVAL); + } + if (cxled->cxld.interleave_ways != 1) { + dev_err(&cxled->cxld.dev, "Interleaving and DCD not supported\n"); + return ERR_PTR(-EINVAL); + } + } do { cxlr = __create_region(cxlrd, mode, atomic_read(&cxlrd->region_id)); @@ -3467,6 +3508,7 @@ static int cxl_region_probe(struct device *dev) case CXL_REGION_PMEM: return devm_cxl_add_pmem_region(cxlr); case CXL_REGION_RAM: + case CXL_REGION_DC: /* * The region can not be manged by CXL if any portion of * it is already online as 'System RAM' diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c index fde29e0ad68b..d8cb5195a227 100644 --- a/drivers/dax/bus.c +++ b/drivers/dax/bus.c @@ -178,6 +178,11 @@ static bool is_static(struct dax_region *dax_region) return (dax_region->res.flags & IORESOURCE_DAX_STATIC) != 0; } +static bool is_sparse(struct dax_region *dax_region) +{ + return (dax_region->res.flags & IORESOURCE_DAX_SPARSE_CAP) != 0; +} + bool static_dev_dax(struct dev_dax *dev_dax) { return is_static(dev_dax->region); @@ -301,6 +306,9 @@ static unsigned long long dax_region_avail_size(struct dax_region *dax_region) lockdep_assert_held(&dax_region_rwsem); + if (is_sparse(dax_region)) + return 0; + for_each_dax_region_resource(dax_region, res) size -= resource_size(res); return size; @@ -1373,6 +1381,8 @@ static umode_t dev_dax_visible(struct kobject *kobj, struct attribute *a, int n) return 0; if (a == &dev_attr_mapping.attr && is_static(dax_region)) return 0; + if (a == &dev_attr_mapping.attr && is_sparse(dax_region)) + return 0; if ((a == &dev_attr_align.attr || a == &dev_attr_size.attr) && is_static(dax_region)) return 0444; diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h index cbbf64443098..783bfeef42cc 100644 --- a/drivers/dax/bus.h +++ b/drivers/dax/bus.h @@ -13,6 +13,7 @@ struct dax_region; /* dax bus specific ioresource flags */ #define IORESOURCE_DAX_STATIC BIT(0) #define IORESOURCE_DAX_KMEM BIT(1) +#define IORESOURCE_DAX_SPARSE_CAP BIT(2) struct dax_region *alloc_dax_region(struct device *parent, int region_id, struct range *range, int target_node, unsigned int align, diff --git a/drivers/dax/cxl.c b/drivers/dax/cxl.c index 9b29e732b39a..367e86b1c22a 100644 --- a/drivers/dax/cxl.c +++ b/drivers/dax/cxl.c @@ -13,19 +13,31 @@ static int cxl_dax_region_probe(struct device *dev) struct cxl_region *cxlr = cxlr_dax->cxlr; struct dax_region *dax_region; struct dev_dax_data data; + resource_size_t dev_size; + unsigned long flags; if (nid == NUMA_NO_NODE) nid = memory_add_physaddr_to_nid(cxlr_dax->hpa_range.start); + flags = IORESOURCE_DAX_KMEM; + if (cxlr->mode == CXL_REGION_DC) + flags |= IORESOURCE_DAX_SPARSE_CAP; + dax_region = alloc_dax_region(dev, cxlr->id, &cxlr_dax->hpa_range, nid, - PMD_SIZE, IORESOURCE_DAX_KMEM); + PMD_SIZE, flags); if (!dax_region) return -ENOMEM; + if (cxlr->mode == CXL_REGION_DC) + /* Add empty seed dax device */ + dev_size = 0; + else + dev_size = range_len(&cxlr_dax->hpa_range); + data = (struct dev_dax_data) { .dax_region = dax_region, .id = -1, - .size = range_len(&cxlr_dax->hpa_range), + .size = dev_size, .memmap_on_memory = true, };