EAL: count nr_overcommit_hugepages as available
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Commit Message
From: Michał Mirosław <michal.miroslaw@atendesoftware.pl>
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>
---
.../linuxapp/eal/eal_hugepage_info.c | 43 ++++++++++++++-----
1 file changed, 32 insertions(+), 11 deletions(-)
Comments
On 25-Feb-19 8:57 PM, Michał Mirosław wrote:
> From: Michał Mirosław <michal.miroslaw@atendesoftware.pl>
>
> 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>
> ---
Surplus pages go back at least as far as 2009, and as far as i can tell,
the patch works under any conditions i thought to throw at it, and
doesn't break anything else. So...
Reviewed-by: Anatoly Burakov <anatoly.burakov@intel.com>
19/03/2019 14:52, Burakov, Anatoly:
> On 25-Feb-19 8:57 PM, Michał Mirosław wrote:
> > From: Michał Mirosław <michal.miroslaw@atendesoftware.pl>
> >
> > 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>
> > ---
>
> Surplus pages go back at least as far as 2009, and as far as i can tell,
> the patch works under any conditions i thought to throw at it, and
> doesn't break anything else. So...
>
> Reviewed-by: Anatoly Burakov <anatoly.burakov@intel.com>
Applied, thanks
And thanks Ferruh for reminding to update this very old patch.
@@ -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)