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mem: count overcommit hugepages as available

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With nr_overcommit_hugepages > 0 application may be able to allocate
hugepages even when free_hugepages == 0. Take this into account when
counting available hugepages.

Signed-off-by: Michał Mirosław <michal.miroslaw@atendesoftware.pl>
Reviewed-by: Anatoly Burakov <anatoly.burakov@intel.com>
This commit is contained in:
Michał Mirosław 2019-02-25 21:57:28 +01:00 committed by Thomas Monjalon
parent 034f1fb616
commit a1c6b70786
1 changed files with 32 additions and 11 deletions
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43
lib/librte_eal/linux/eal/eal_hugepage_info.c
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@ -70,30 +70,38 @@ create_shared_memory(const char *filename, const size_t mem_size)
return map_shared_memory(filename, mem_size, O_RDWR | O_CREAT);
}
static int get_hp_sysfs_value(const char *subdir, const char *file, unsigned long *val)
{
char path[PATH_MAX];
snprintf(path, sizeof(path), "%s/%s/%s",
sys_dir_path, subdir, file);
return eal_parse_sysfs_value(path, val);
}
/* this function is only called from eal_hugepage_info_init which itself
* is only called from a primary process */
static uint32_t
get_num_hugepages(const char *subdir)
{
char path[PATH_MAX];
long unsigned resv_pages, num_pages = 0;
unsigned long resv_pages, num_pages, over_pages, surplus_pages;
const char *nr_hp_file = "free_hugepages";
const char *nr_rsvd_file = "resv_hugepages";
const char *nr_over_file = "nr_overcommit_hugepages";
const char *nr_splus_file = "surplus_hugepages";
/* first, check how many reserved pages kernel reports */
snprintf(path, sizeof(path), "%s/%s/%s",
sys_dir_path, subdir, nr_rsvd_file);
if (eal_parse_sysfs_value(path, &resv_pages) < 0)
if (get_hp_sysfs_value(subdir, nr_rsvd_file, &resv_pages) < 0)
return 0;
snprintf(path, sizeof(path), "%s/%s/%s",
sys_dir_path, subdir, nr_hp_file);
if (eal_parse_sysfs_value(path, &num_pages) < 0)
if (get_hp_sysfs_value(subdir, nr_hp_file, &num_pages) < 0)
return 0;
if (num_pages == 0)
RTE_LOG(WARNING, EAL, "No free hugepages reported in %s\n",
subdir);
if (get_hp_sysfs_value(subdir, nr_over_file, &over_pages) < 0)
over_pages = 0;
if (get_hp_sysfs_value(subdir, nr_splus_file, &surplus_pages) < 0)
surplus_pages = 0;
/* adjust num_pages */
if (num_pages >= resv_pages)
@ -101,6 +109,19 @@ get_num_hugepages(const char *subdir)
else if (resv_pages)
num_pages = 0;
if (over_pages >= surplus_pages)
over_pages -= surplus_pages;
else
over_pages = 0;
if (num_pages == 0 && over_pages == 0)
RTE_LOG(WARNING, EAL, "No available hugepages reported in %s\n",
subdir);
num_pages += over_pages;
if (num_pages < over_pages) /* overflow */
num_pages = UINT32_MAX;
/* we want to return a uint32_t and more than this looks suspicious
* anyway ... */
if (num_pages > UINT32_MAX)