Re: [ndctl PATCHv4] ndctl: Use max_available_extent for namespace

Masayoshi Mizuma
2018-08-02T19:49:56Z

Hi Keith,

I tested your patch with the following test script.
The result is good to me.

Please feel free to add:

Tested-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>

Test script:
---
#!/bin/bash -Ex

NDCTL=./ndctl/ndctl

modprobe nfit_test
region=$($NDCTL list -b nfit_test.0 -R -t pmem | jq -r .[].dev | head -1)

available_sz=$($NDCTL list -r $region | jq -r .[].available_size)
size=$(( available_sz/4 ))

NS1=$($NDCTL create-namespace -r $region -t pmem -s $size | jq -r .dev)
NS2=$($NDCTL create-namespace -r $region -t pmem -s $size | jq -r .dev)
NS3=$($NDCTL create-namespace -r $region -t pmem -s $size | jq -r .dev)

$NDCTL disable-namespace $NS2
$NDCTL destroy-namespace $NS2

$NDCTL list -r $region

$NDCTL create-namespace -r $region -t pmem
ret=$?

$NDCTL disable-region all
modprobe -r nfit_test

exit $ret
---

Thanks,
Masa

On 07/24/2018 06:31 PM, Keith Busch wrote:
> The available_size attribute returns all the unused regions, but a
> memory namespace has to use contiguous free regions. This patch uses the
> max_available_extent attribute, which reports the largest capacity that
> can be created when determining what size to allocate.
>
> If the attribute is available, this patch will also report the max
> available extent in the region list output.
>
> Signed-off-by: Keith Busch <keith.busch@intel.com>
> ---
> v3 -> v4:
>
> Moved the symbol to the appropriate version section of the symbols
> script.
>
> Report the max available extent in the region list if the attribute
> exists.
>
> ndctl/lib/libndctl.c | 33 +++++++++++++++++++++++++++++++++
> ndctl/lib/libndctl.sym | 1 +
> ndctl/libndctl.h | 2 ++
> ndctl/list.c | 9 +++++++++
> ndctl/namespace.c | 4 +++-
> 5 files changed, 48 insertions(+), 1 deletion(-)
>
> diff --git a/ndctl/lib/libndctl.c b/ndctl/lib/libndctl.c
> index 969e4aa..e911ea2 100644
> --- a/ndctl/lib/libndctl.c
> +++ b/ndctl/lib/libndctl.c
> @@ -2107,6 +2107,39 @@ NDCTL_EXPORT unsigned long long ndctl_region_get_available_size(
> return strtoull(buf, NULL, 0);
> }
>
> +NDCTL_EXPORT unsigned long long ndctl_region_get_max_available_extent(
> + struct ndctl_region *region)
> +{
> + unsigned int nstype = ndctl_region_get_nstype(region);
> + struct ndctl_ctx *ctx = ndctl_region_get_ctx(region);
> + char *path = region->region_buf;
> + int len = region->buf_len;
> + char buf[SYSFS_ATTR_SIZE];
> +
> + switch (nstype) {
> + case ND_DEVICE_NAMESPACE_PMEM:
> + case ND_DEVICE_NAMESPACE_BLK:
> + break;
> + default:
> + return 0;
> + }
> +
> + if (snprintf(path, len,
> + "%s/max_available_extent", region->region_path) >= len) {
> + err(ctx, "%s: buffer too small!\n",
> + ndctl_region_get_devname(region));
> + return ULLONG_MAX;
> + }
> +
> + /* fall back to legacy behavior if max extents is not exported */
> + if (sysfs_read_attr(ctx, path, buf) < 0) {
> + dbg(ctx, "max extents attribute not exported on older kernels\n");
> + return ULLONG_MAX;
> + }
> +
> + return strtoull(buf, NULL, 0);
> +}
> +
> NDCTL_EXPORT unsigned int ndctl_region_get_range_index(struct ndctl_region *region)
> {
> return region->range_index;
> diff --git a/ndctl/lib/libndctl.sym b/ndctl/lib/libndctl.sym
> index 9b36960..2bc312d 100644
> --- a/ndctl/lib/libndctl.sym
> +++ b/ndctl/lib/libndctl.sym
> @@ -375,4 +375,5 @@ global:
> ndctl_dimm_get_flags;
> ndctl_dimm_get_event_flags;
> ndctl_dimm_is_flag_supported;
> + ndctl_region_get_max_available_extent;
> } LIBNDCTL_16;
> diff --git a/ndctl/libndctl.h b/ndctl/libndctl.h
> index 6a6bb0d..a146502 100644
> --- a/ndctl/libndctl.h
> +++ b/ndctl/libndctl.h
> @@ -350,6 +350,8 @@ unsigned int ndctl_region_get_interleave_ways(struct ndctl_region *region);
> unsigned int ndctl_region_get_mappings(struct ndctl_region *region);
> unsigned long long ndctl_region_get_size(struct ndctl_region *region);
> unsigned long long ndctl_region_get_available_size(struct ndctl_region *region);
> +unsigned long long ndctl_region_get_max_available_extent(
> + struct ndctl_region *region);
> unsigned int ndctl_region_get_range_index(struct ndctl_region *region);
> unsigned int ndctl_region_get_type(struct ndctl_region *region);
> struct ndctl_namespace *ndctl_region_get_namespace_seed(
> diff --git a/ndctl/list.c b/ndctl/list.c
> index a06edc9..82e88bb 100644
> --- a/ndctl/list.c
> +++ b/ndctl/list.c
> @@ -72,6 +72,7 @@ static struct json_object *region_to_json(struct ndctl_region *region,
> struct ndctl_interleave_set *iset;
> struct ndctl_mapping *mapping;
> unsigned int bb_count = 0;
> + unsigned long long extent;
> enum ndctl_persistence_domain pd;
> int numa;
>
> @@ -94,6 +95,14 @@ static struct json_object *region_to_json(struct ndctl_region *region,
> goto err;
> json_object_object_add(jregion, "available_size", jobj);
>
> + extent = ndctl_region_get_max_available_extent(region);
> + if (extent != ULLONG_MAX) {
> + jobj = util_json_object_size(extent, flags);
> + if (!jobj)
> + goto err;
> + json_object_object_add(jregion, "max_available_extent", jobj);
> + }
> +
> switch (ndctl_region_get_type(region)) {
> case ND_DEVICE_REGION_PMEM:
> jobj = json_object_new_string("pmem");
> diff --git a/ndctl/namespace.c b/ndctl/namespace.c
> index fe86d82..cfe0559 100644
> --- a/ndctl/namespace.c
> +++ b/ndctl/namespace.c
> @@ -764,7 +764,9 @@ static int namespace_create(struct ndctl_region *region)
> return -EAGAIN;
> }
>
> - available = ndctl_region_get_available_size(region);
> + available = ndctl_region_get_max_available_extent(region);
> + if (available == ULLONG_MAX)
> + available = ndctl_region_get_available_size(region);
> if (!available || p.size > available) {
> debug("%s: insufficient capacity size: %llx avail: %llx\n",
> devname, p.size, available);