libnvdimm, region: update nd_region_available_dpa() for multi-pmem support

The free dpa (dimm-physical-address) space calculation reports how much
free space is available with consideration for aliased BLK + PMEM
regions.  Recall that BLK capacity is allocated from high addresses and
PMEM is allocated from low addresses in their respective regions.

nd_region_available_dpa() accounts for the fact that the largest
encroachment (lowest starting address) into PMEM capacity by a BLK
allocation limits the available capacity to that point, regardless if
there is BLK allocation hole at a higher address.  Similarly, for the
multi-pmem case we need to track the largest encroachment (highest
 ending address) of a PMEM allocation in BLK capacity regardless of
whether there is an allocation hole that a BLK allocation could fill at
a lower address.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c
index cf36470..4b0296c 100644 (file)
--- a/drivers/nvdimm/dimm_devs.c
+++ b/drivers/nvdimm/dimm_devs.c
@@ -386,40 +386,148 @@ struct nvdimm *nvdimm_create(struct nvdimm_bus *nvdimm_bus, void *provider_data,
 }
 EXPORT_SYMBOL_GPL(nvdimm_create);
 
+struct blk_alloc_info {
+       struct nd_mapping *nd_mapping;
+       resource_size_t available, busy;
+       struct resource *res;
+};
+
+static int alias_dpa_busy(struct device *dev, void *data)
+{
+       resource_size_t map_end, blk_start, new, busy;
+       struct blk_alloc_info *info = data;
+       struct nd_mapping *nd_mapping;
+       struct nd_region *nd_region;
+       struct nvdimm_drvdata *ndd;
+       struct resource *res;
+       int i;
+
+       if (!is_nd_pmem(dev))
+               return 0;
+
+       nd_region = to_nd_region(dev);
+       for (i = 0; i < nd_region->ndr_mappings; i++) {
+               nd_mapping  = &nd_region->mapping[i];
+               if (nd_mapping->nvdimm == info->nd_mapping->nvdimm)
+                       break;
+       }
+
+       if (i >= nd_region->ndr_mappings)
+               return 0;
+
+       ndd = to_ndd(nd_mapping);
+       map_end = nd_mapping->start + nd_mapping->size - 1;
+       blk_start = nd_mapping->start;
+ retry:
+       /*
+        * Find the free dpa from the end of the last pmem allocation to
+        * the end of the interleave-set mapping that is not already
+        * covered by a blk allocation.
+        */
+       busy = 0;
+       for_each_dpa_resource(ndd, res) {
+               if ((res->start >= blk_start && res->start < map_end)
+                               || (res->end >= blk_start
+                                       && res->end <= map_end)) {
+                       if (strncmp(res->name, "pmem", 4) == 0) {
+                               new = max(blk_start, min(map_end + 1,
+                                                       res->end + 1));
+                               if (new != blk_start) {
+                                       blk_start = new;
+                                       goto retry;
+                               }
+                       } else
+                               busy += min(map_end, res->end)
+                                       - max(nd_mapping->start, res->start) + 1;
+               } else if (nd_mapping->start > res->start
+                               && map_end < res->end) {
+                       /* total eclipse of the PMEM region mapping */
+                       busy += nd_mapping->size;
+                       break;
+               }
+       }
+
+       info->available -= blk_start - nd_mapping->start + busy;
+       return 0;
+}
+
+static int blk_dpa_busy(struct device *dev, void *data)
+{
+       struct blk_alloc_info *info = data;
+       struct nd_mapping *nd_mapping;
+       struct nd_region *nd_region;
+       resource_size_t map_end;
+       int i;
+
+       if (!is_nd_pmem(dev))
+               return 0;
+
+       nd_region = to_nd_region(dev);
+       for (i = 0; i < nd_region->ndr_mappings; i++) {
+               nd_mapping  = &nd_region->mapping[i];
+               if (nd_mapping->nvdimm == info->nd_mapping->nvdimm)
+                       break;
+       }
+
+       if (i >= nd_region->ndr_mappings)
+               return 0;
+
+       map_end = nd_mapping->start + nd_mapping->size - 1;
+       if (info->res->start >= nd_mapping->start
+                       && info->res->start < map_end) {
+               if (info->res->end <= map_end) {
+                       info->busy = 0;
+                       return 1;
+               } else {
+                       info->busy -= info->res->end - map_end;
+                       return 0;
+               }
+       } else if (info->res->end >= nd_mapping->start
+                       && info->res->end <= map_end) {
+               info->busy -= nd_mapping->start - info->res->start;
+               return 0;
+       } else {
+               info->busy -= nd_mapping->size;
+               return 0;
+       }
+}
+
 /**
  * nd_blk_available_dpa - account the unused dpa of BLK region
  * @nd_mapping: container of dpa-resource-root + labels
  *
- * Unlike PMEM, BLK namespaces can occupy discontiguous DPA ranges.
+ * Unlike PMEM, BLK namespaces can occupy discontiguous DPA ranges, but
+ * we arrange for them to never start at an lower dpa than the last
+ * PMEM allocation in an aliased region.
  */
-resource_size_t nd_blk_available_dpa(struct nd_mapping *nd_mapping)
+resource_size_t nd_blk_available_dpa(struct nd_region *nd_region)
 {
+       struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(&nd_region->dev);
+       struct nd_mapping *nd_mapping = &nd_region->mapping[0];
        struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
-       resource_size_t map_end, busy = 0, available;
+       struct blk_alloc_info info = {
+               .nd_mapping = nd_mapping,
+               .available = nd_mapping->size,
+       };
        struct resource *res;
 
        if (!ndd)
                return 0;
 
-       map_end = nd_mapping->start + nd_mapping->size - 1;
-       for_each_dpa_resource(ndd, res)
-               if (res->start >= nd_mapping->start && res->start < map_end) {
-                       resource_size_t end = min(map_end, res->end);
+       device_for_each_child(&nvdimm_bus->dev, &info, alias_dpa_busy);
 
-                       busy += end - res->start + 1;
-               } else if (res->end >= nd_mapping->start
-                               && res->end <= map_end) {
-                       busy += res->end - nd_mapping->start;
-               } else if (nd_mapping->start > res->start
-                               && nd_mapping->start < res->end) {
-                       /* total eclipse of the BLK region mapping */
-                       busy += nd_mapping->size;
-               }
+       /* now account for busy blk allocations in unaliased dpa */
+       for_each_dpa_resource(ndd, res) {
+               if (strncmp(res->name, "blk", 3) != 0)
+                       continue;
 
-       available = map_end - nd_mapping->start + 1;
-       if (busy < available)
-               return available - busy;
-       return 0;
+               info.res = res;
+               info.busy = resource_size(res);
+               device_for_each_child(&nvdimm_bus->dev, &info, blk_dpa_busy);
+               info.available -= info.busy;
+       }
+
+       return info.available;
 }
 
 /**
@@ -451,21 +559,16 @@ resource_size_t nd_pmem_available_dpa(struct nd_region *nd_region,
        map_start = nd_mapping->start;
        map_end = map_start + nd_mapping->size - 1;
        blk_start = max(map_start, map_end + 1 - *overlap);
-       for_each_dpa_resource(ndd, res)
+       for_each_dpa_resource(ndd, res) {
                if (res->start >= map_start && res->start < map_end) {
                        if (strncmp(res->name, "blk", 3) == 0)
-                               blk_start = min(blk_start, res->start);
-                       else if (res->start != map_start) {
+                               blk_start = min(blk_start,
+                                               max(map_start, res->start));
+                       else if (res->end > map_end) {
                                reason = "misaligned to iset";
                                goto err;
-                       } else {
-                               if (busy) {
-                                       reason = "duplicate overlapping PMEM reservations?";
-                                       goto err;
-                               }
+                       } else
                                busy += resource_size(res);
-                               continue;
-                       }
                } else if (res->end >= map_start && res->end <= map_end) {
                        if (strncmp(res->name, "blk", 3) == 0) {
                                /*
@@ -474,15 +577,14 @@ resource_size_t nd_pmem_available_dpa(struct nd_region *nd_region,
                                 * be used for BLK.
                                 */
                                blk_start = map_start;
-                       } else {
-                               reason = "misaligned to iset";
-                               goto err;
-                       }
+                       } else
+                               busy += resource_size(res);
                } else if (map_start > res->start && map_start < res->end) {
                        /* total eclipse of the mapping */
                        busy += nd_mapping->size;
                        blk_start = map_start;
                }
+       }
 
        *overlap = map_end + 1 - blk_start;
        available = blk_start - map_start;
@@ -491,10 +593,6 @@ resource_size_t nd_pmem_available_dpa(struct nd_region *nd_region,
        return 0;
 
  err:
-       /*
-        * Something is wrong, PMEM must align with the start of the
-        * interleave set, and there can only be one allocation per set.
-        */
        nd_dbg_dpa(nd_region, ndd, res, "%s\n", reason);
        return 0;
 }

diff --git a/drivers/nvdimm/nd-core.h b/drivers/nvdimm/nd-core.h
index fb3ade0..7c2196a 100644 (file)
--- a/drivers/nvdimm/nd-core.h
+++ b/drivers/nvdimm/nd-core.h
@@ -76,7 +76,7 @@ struct nd_mapping;
 void nd_mapping_free_labels(struct nd_mapping *nd_mapping);
 resource_size_t nd_pmem_available_dpa(struct nd_region *nd_region,
                struct nd_mapping *nd_mapping, resource_size_t *overlap);
-resource_size_t nd_blk_available_dpa(struct nd_mapping *nd_mapping);
+resource_size_t nd_blk_available_dpa(struct nd_region *nd_region);
 resource_size_t nd_region_available_dpa(struct nd_region *nd_region);
 resource_size_t nvdimm_allocated_dpa(struct nvdimm_drvdata *ndd,
                struct nd_label_id *label_id);

diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index 19bcd68..3ac534a 100644 (file)
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -294,9 +294,8 @@ resource_size_t nd_region_available_dpa(struct nd_region *nd_region)
                                blk_max_overlap = overlap;
                                goto retry;
                        }
-               } else if (is_nd_blk(&nd_region->dev)) {
-                       available += nd_blk_available_dpa(nd_mapping);
-               }
+               } else if (is_nd_blk(&nd_region->dev))
+                       available += nd_blk_available_dpa(nd_region);
        }
 
        return available;