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libnvdimm, region: update nd_region_available_dpa() for multi-pmem su…
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…pport

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>
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Dan Williams committed Oct 7, 2016
1 parent 6ff3e91 commit a1f3e4d
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Showing 3 changed files with 139 additions and 42 deletions.
174 changes: 136 additions & 38 deletions drivers/nvdimm/dimm_devs.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
}

/**
Expand Down Expand Up @@ -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) {
/*
Expand All @@ -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;
Expand All @@ -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;
}
Expand Down
2 changes: 1 addition & 1 deletion drivers/nvdimm/nd-core.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down
5 changes: 2 additions & 3 deletions drivers/nvdimm/region_devs.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down

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