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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>
alistair/sensors
Dan Williams 2020-01-30 12:06:23 -08:00
parent a0e374525d
commit 2522afb86a
4 changed files with 193 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

86
drivers/nvdimm/dimm_devs.c
View File

@ -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:

9
drivers/nvdimm/namespace_devs.c
View File

@ -542,6 +542,11 @@ static void space_valid(struct nd_region *nd_region, struct nvdimm_drvdata *ndd,
{
bool is_reserve = strcmp(label_id->id, "pmem-reserve") == 0;
bool is_pmem = strncmp(label_id->id, "pmem", 4) == 0;
unsigned long align;
align = nd_region->align / nd_region->ndr_mappings;
valid->start = ALIGN(valid->start, align);
valid->end = ALIGN_DOWN(valid->end + 1, align) - 1;
if (valid->start >= valid->end)
goto invalid;
@ -981,10 +986,10 @@ static ssize_t __size_store(struct device *dev, unsigned long long val)
return -ENXIO;
}
div_u64_rem(val, PAGE_SIZE * nd_region->ndr_mappings, &remainder);
div_u64_rem(val, nd_region->align, &remainder);
if (remainder) {
dev_dbg(dev, "%llu is not %ldK aligned\n", val,
(PAGE_SIZE * nd_region->ndr_mappings) / SZ_1K);
nd_region->align / SZ_1K);
return -EINVAL;
}

1
drivers/nvdimm/nd.h
View File

@ -146,6 +146,7 @@ struct nd_region {
struct device *btt_seed;
struct device *pfn_seed;
struct device *dax_seed;
unsigned long align;
u16 ndr_mappings;
u64 ndr_size;
u64 ndr_start;

124
drivers/nvdimm/region_devs.c
View File

@ -216,21 +216,25 @@ int nd_region_to_nstype(struct nd_region *nd_region)
}
EXPORT_SYMBOL(nd_region_to_nstype);
static unsigned long long region_size(struct nd_region *nd_region)
{
if (is_memory(&nd_region->dev)) {
return nd_region->ndr_size;
} else if (nd_region->ndr_mappings == 1) {
struct nd_mapping *nd_mapping = &nd_region->mapping[0];
return nd_mapping->size;
}
return 0;
}
static ssize_t size_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct nd_region *nd_region = to_nd_region(dev);
unsigned long long size = 0;
if (is_memory(dev)) {
size = nd_region->ndr_size;
} else if (nd_region->ndr_mappings == 1) {
struct nd_mapping *nd_mapping = &nd_region->mapping[0];
size = nd_mapping->size;
}
return sprintf(buf, "%llu\n", size);
return sprintf(buf, "%llu\n", region_size(nd_region));
}
static DEVICE_ATTR_RO(size);
@ -529,6 +533,55 @@ static ssize_t read_only_store(struct device *dev,
}
static DEVICE_ATTR_RW(read_only);
static ssize_t align_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct nd_region *nd_region = to_nd_region(dev);
return sprintf(buf, "%#lx\n", nd_region->align);
}
static ssize_t align_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
struct nd_region *nd_region = to_nd_region(dev);
unsigned long val, dpa;
u32 remainder;
int rc;
rc = kstrtoul(buf, 0, &val);
if (rc)
return rc;
if (!nd_region->ndr_mappings)
return -ENXIO;
/*
* Ensure space-align is evenly divisible by the region
* interleave-width because the kernel typically has no facility
* to determine which DIMM(s), dimm-physical-addresses, would
* contribute to the tail capacity in system-physical-address
* space for the namespace.
*/
dpa = val;
remainder = do_div(dpa, nd_region->ndr_mappings);
if (!is_power_of_2(dpa) || dpa < PAGE_SIZE
|| val > region_size(nd_region) || remainder)
return -EINVAL;
/*
* Given that space allocation consults this value multiple
* times ensure it does not change for the duration of the
* allocation.
*/
nvdimm_bus_lock(dev);
nd_region->align = val;
nvdimm_bus_unlock(dev);
return len;
}
static DEVICE_ATTR_RW(align);
static ssize_t region_badblocks_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@ -571,6 +624,7 @@ static DEVICE_ATTR_RO(persistence_domain);
static struct attribute *nd_region_attributes[] = {
&dev_attr_size.attr,
&dev_attr_align.attr,
&dev_attr_nstype.attr,
&dev_attr_mappings.attr,
&dev_attr_btt_seed.attr,
@ -626,6 +680,19 @@ static umode_t region_visible(struct kobject *kobj, struct attribute *a, int n)
return a->mode;
}
if (a == &dev_attr_align.attr) {
int i;
for (i = 0; i < nd_region->ndr_mappings; i++) {
struct nd_mapping *nd_mapping = &nd_region->mapping[i];
struct nvdimm *nvdimm = nd_mapping->nvdimm;
if (test_bit(NDD_LABELING, &nvdimm->flags))
return a->mode;
}
return 0;
}
if (a != &dev_attr_set_cookie.attr
&& a != &dev_attr_available_size.attr)
return a->mode;
@ -935,6 +1002,42 @@ void nd_region_release_lane(struct nd_region *nd_region, unsigned int lane)
}
EXPORT_SYMBOL(nd_region_release_lane);
/*
* PowerPC requires this alignment for memremap_pages(). All other archs
* should be ok with SUBSECTION_SIZE (see memremap_compat_align()).
*/
#define MEMREMAP_COMPAT_ALIGN_MAX SZ_16M
static unsigned long default_align(struct nd_region *nd_region)
{
unsigned long align, per_mapping;
int i, mappings;
u32 remainder;
if (is_nd_blk(&nd_region->dev))
align = PAGE_SIZE;
else
align = MEMREMAP_COMPAT_ALIGN_MAX;
for (i = 0; i < nd_region->ndr_mappings; i++) {
struct nd_mapping *nd_mapping = &nd_region->mapping[i];
struct nvdimm *nvdimm = nd_mapping->nvdimm;
if (test_bit(NDD_ALIASING, &nvdimm->flags)) {
align = MEMREMAP_COMPAT_ALIGN_MAX;
break;
}
}
mappings = max_t(u16, 1, nd_region->ndr_mappings);
per_mapping = align;
remainder = do_div(per_mapping, mappings);
if (remainder)
align *= mappings;
return align;
}
static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
struct nd_region_desc *ndr_desc,
const struct device_type *dev_type, const char *caller)
@ -1039,6 +1142,7 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
dev->of_node = ndr_desc->of_node;
nd_region->ndr_size = resource_size(ndr_desc->res);
nd_region->ndr_start = ndr_desc->res->start;
nd_region->align = default_align(nd_region);
if (ndr_desc->flush)
nd_region->flush = ndr_desc->flush;
else