libnvdimm/region: Introduce an 'align' attribute
The align attribute applies an alignment constraint for namespace
creation in a region. Whereas the 'align' attribute of a namespace
applied alignment padding via an info block, the 'align' attribute
applies alignment constraints to the free space allocation.
The default for 'align' is the maximum known memremap_compat_align()
across all archs (16MiB from PowerPC at time of writing) multiplied by
the number of interleave ways if there is blk-aliasing. The minimum is
PAGE_SIZE and allows for the creation of cross-arch incompatible
namespaces, just as previous kernels allowed, but the expectation is
cross-arch and mode-independent compatibility by default.
The regression risk with this change is limited to cases that were
dependent on the ability to create unaligned namespaces, *and* for some
reason are unable to opt-out of aligned namespaces by writing to
'regionX/align'. If such a scenario arises the default can be flipped
from opt-out to opt-in of compat-aligned namespace creation, but that is
a last resort. The kernel will otherwise continue to support existing
defined misaligned namespaces.
Unfortunately this change needs to touch several parts of the
implementation at once:
- region/available_size: expand busy extents to current align
- region/max_available_extent: expand busy extents to current align
- namespace/size: trim free space to current align
...to keep the free space accounting conforming to the dynamic align
setting.
Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reported-by: Jeff Moyer <jmoyer@redhat.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Link: https://lore.kernel.org/r/158041478371.3889308.14542630147672668068.stgit@dwillia2-desk3.amr.corp.intel.com
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 39a61a5..b7b77e8 100644
--- a/drivers/nvdimm/dimm_devs.c
+++ b/drivers/nvdimm/dimm_devs.c
@@ -563,6 +563,21 @@ int nvdimm_security_freeze(struct nvdimm *nvdimm)
return rc;
}
+static unsigned long dpa_align(struct nd_region *nd_region)
+{
+ struct device *dev = &nd_region->dev;
+
+ if (dev_WARN_ONCE(dev, !is_nvdimm_bus_locked(dev),
+ "bus lock required for capacity provision\n"))
+ return 0;
+ if (dev_WARN_ONCE(dev, !nd_region->ndr_mappings || nd_region->align
+ % nd_region->ndr_mappings,
+ "invalid region align %#lx mappings: %d\n",
+ nd_region->align, nd_region->ndr_mappings))
+ return 0;
+ return nd_region->align / nd_region->ndr_mappings;
+}
+
int alias_dpa_busy(struct device *dev, void *data)
{
resource_size_t map_end, blk_start, new;
@@ -571,6 +586,7 @@ int alias_dpa_busy(struct device *dev, void *data)
struct nd_region *nd_region;
struct nvdimm_drvdata *ndd;
struct resource *res;
+ unsigned long align;
int i;
if (!is_memory(dev))
@@ -608,13 +624,21 @@ int alias_dpa_busy(struct device *dev, void *data)
* Find the free dpa from the end of the last pmem allocation to
* the end of the interleave-set mapping.
*/
+ align = dpa_align(nd_region);
+ if (!align)
+ return 0;
+
for_each_dpa_resource(ndd, res) {
+ resource_size_t start, end;
+
if (strncmp(res->name, "pmem", 4) != 0)
continue;
- if ((res->start >= blk_start && res->start < map_end)
- || (res->end >= blk_start
- && res->end <= map_end)) {
- new = max(blk_start, min(map_end + 1, res->end + 1));
+
+ start = ALIGN_DOWN(res->start, align);
+ end = ALIGN(res->end + 1, align) - 1;
+ if ((start >= blk_start && start < map_end)
+ || (end >= blk_start && end <= map_end)) {
+ new = max(blk_start, min(map_end, end) + 1);
if (new != blk_start) {
blk_start = new;
goto retry;
@@ -654,6 +678,7 @@ resource_size_t nd_blk_available_dpa(struct nd_region *nd_region)
.res = NULL,
};
struct resource *res;
+ unsigned long align;
if (!ndd)
return 0;
@@ -661,10 +686,20 @@ resource_size_t nd_blk_available_dpa(struct nd_region *nd_region)
device_for_each_child(&nvdimm_bus->dev, &info, alias_dpa_busy);
/* now account for busy blk allocations in unaliased dpa */
+ align = dpa_align(nd_region);
+ if (!align)
+ return 0;
for_each_dpa_resource(ndd, res) {
+ resource_size_t start, end, size;
+
if (strncmp(res->name, "blk", 3) != 0)
continue;
- info.available -= resource_size(res);
+ start = ALIGN_DOWN(res->start, align);
+ end = ALIGN(res->end + 1, align) - 1;
+ size = end - start + 1;
+ if (size >= info.available)
+ return 0;
+ info.available -= size;
}
return info.available;
@@ -683,19 +718,31 @@ resource_size_t nd_pmem_max_contiguous_dpa(struct nd_region *nd_region,
struct nvdimm_bus *nvdimm_bus;
resource_size_t max = 0;
struct resource *res;
+ unsigned long align;
/* if a dimm is disabled the available capacity is zero */
if (!ndd)
return 0;
+ align = dpa_align(nd_region);
+ if (!align)
+ return 0;
+
nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
if (__reserve_free_pmem(&nd_region->dev, nd_mapping->nvdimm))
return 0;
for_each_dpa_resource(ndd, res) {
+ resource_size_t start, end;
+
if (strcmp(res->name, "pmem-reserve") != 0)
continue;
- if (resource_size(res) > max)
- max = resource_size(res);
+ /* trim free space relative to current alignment setting */
+ start = ALIGN(res->start, align);
+ end = ALIGN_DOWN(res->end + 1, align) - 1;
+ if (end < start)
+ continue;
+ if (end - start + 1 > max)
+ max = end - start + 1;
}
release_free_pmem(nvdimm_bus, nd_mapping);
return max;
@@ -723,24 +770,33 @@ resource_size_t nd_pmem_available_dpa(struct nd_region *nd_region,
struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
struct resource *res;
const char *reason;
+ unsigned long align;
if (!ndd)
return 0;
+ align = dpa_align(nd_region);
+ if (!align)
+ return 0;
+
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) {
- if (res->start >= map_start && res->start < map_end) {
+ resource_size_t start, end;
+
+ start = ALIGN_DOWN(res->start, align);
+ end = ALIGN(res->end + 1, align) - 1;
+ if (start >= map_start && start < map_end) {
if (strncmp(res->name, "blk", 3) == 0)
blk_start = min(blk_start,
- max(map_start, res->start));
- else if (res->end > map_end) {
+ max(map_start, start));
+ else if (end > map_end) {
reason = "misaligned to iset";
goto err;
} else
- busy += resource_size(res);
- } else if (res->end >= map_start && res->end <= map_end) {
+ busy += end - start + 1;
+ } else if (end >= map_start && end <= map_end) {
if (strncmp(res->name, "blk", 3) == 0) {
/*
* If a BLK allocation overlaps the start of
@@ -749,8 +805,8 @@ resource_size_t nd_pmem_available_dpa(struct nd_region *nd_region,
*/
blk_start = map_start;
} else
- busy += resource_size(res);
- } else if (map_start > res->start && map_start < res->end) {
+ busy += end - start + 1;
+ } else if (map_start > start && map_start < end) {
/* total eclipse of the mapping */
busy += nd_mapping->size;
blk_start = map_start;
@@ -760,7 +816,7 @@ resource_size_t nd_pmem_available_dpa(struct nd_region *nd_region,
*overlap = map_end + 1 - blk_start;
available = blk_start - map_start;
if (busy < available)
- return available - busy;
+ return ALIGN_DOWN(available - busy, align);
return 0;
err: