This patch enables calculating space left in a hugetlbfs.
There are three sources to get the information: 1. from
sysfs; 2. from option size specified when mount; 3. use
statfs. We should use the minimum one of these three sizes.

Signed-off-by: Jianfeng Tan <jianfeng.tan at intel.com>
---
 lib/librte_eal/linuxapp/eal/eal_hugepage_info.c | 85 ++++++++++++++++++++++++-
 1 file changed, 84 insertions(+), 1 deletion(-)

diff --git a/lib/librte_eal/linuxapp/eal/eal_hugepage_info.c 
b/lib/librte_eal/linuxapp/eal/eal_hugepage_info.c
index 18858e2..6db8c33 100644
--- a/lib/librte_eal/linuxapp/eal/eal_hugepage_info.c
+++ b/lib/librte_eal/linuxapp/eal/eal_hugepage_info.c
@@ -44,6 +44,8 @@
 #include <unistd.h>
 #include <errno.h>
 #include <sys/queue.h>
+#include <sys/vfs.h>
+#include <mntent.h>

 #include <rte_memory.h>
 #include <rte_memzone.h>
@@ -189,6 +191,70 @@ get_hugepage_dir(uint64_t hugepage_sz)
        return retval;
 }

+/* Caller to make sure this mnt_dir exist
+ */
+static uint64_t
+get_hugetlbfs_mount_size(const char *mnt_dir)
+{
+       char *start, *end, *opt_size;
+       struct mntent *ent;
+       uint64_t size;
+       FILE *f;
+       int len;
+
+       f = setmntent("/proc/mounts", "r");
+       if (f == NULL) {
+               RTE_LOG(ERR, EAL, "setmntent() error: %s\n",
+                       strerror(errno));
+               return 0;
+       }
+       while (NULL != (ent = getmntent(f))) {
+               if (!strcmp(ent->mnt_dir, mnt_dir))
+                       break;
+       }
+
+       start = hasmntopt(ent, "size");
+       if (start == NULL) {
+               RTE_LOG(DEBUG, EAL, "option size not specified for %s\n",
+                       mnt_dir);
+               size = 0;
+               goto end;
+       }
+       start += strlen("size=");
+       end = strstr(start, ",");
+       if (end != NULL)
+               len = end - start;
+       else
+               len = strlen(start);
+       opt_size = strndup(start, len);
+       size = rte_str_to_size(opt_size);
+       free(opt_size);
+
+end:
+       endmntent(f);
+       return size;
+}
+
+/* Caller to make sure this mount has option size
+ * so that statfs is not zero.
+ */
+static uint64_t
+get_hugetlbfs_free_size(const char *mnt_dir)
+{
+       int r;
+       struct statfs stats;
+
+       r = statfs(mnt_dir, &stats);
+       if (r != 0) {
+               RTE_LOG(ERR, EAL, "statfs() error: %s\n",
+                       strerror(errno));
+               return 0;
+       }
+
+       return stats.f_bfree * stats.f_bsize;
+}
+
+
 /*
  * Clear the hugepage directory of whatever hugepage files
  * there are. Checks if the file is locked (i.e.
@@ -329,9 +395,26 @@ eal_hugepage_info_init(void)
                if (clear_hugedir(hpi->hugedir) == -1)
                        break;

+               /* there are three souces of how much space left in a
+                * hugetlbfs dir.
+                */
+               uint64_t sz_left, sz_sysfs, sz_option, sz_statfs;
+
+               sz_sysfs = get_num_hugepages(dirent->d_name) *
+                       hpi->hugepage_sz;
+               sz_left = sz_sysfs;
+               sz_option = get_hugetlbfs_mount_size(hpi->hugedir);
+               if (sz_option) {
+                       sz_statfs = get_hugetlbfs_free_size(hpi->hugedir);
+                       sz_left = RTE_MIN(sz_sysfs, sz_statfs);
+                       RTE_LOG(INFO, "sz_sysfs: %"PRIu64", sz_option: "
+                                       "%"PRIu64", sz_statfs: %"PRIu64"\n",
+                                       sz_sysfs, sz_option, sz_statfs);
+               }
+
                /* for now, put all pages into socket 0,
                 * later they will be sorted */
-               hpi->num_pages[0] = get_num_hugepages(dirent->d_name);
+               hpi->num_pages[0] = sz_left / hpi->hugepage_sz;

 #ifndef RTE_ARCH_64
                /* for 32-bit systems, limit number of hugepages to
-- 
2.1.4

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