mem: support --huge-unlink mode

Unlink hugepages after creating them, to honor the hugepage-unlink mode.
We cannot resize non-existing files, so make single file segments
explicitly unsupported.

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>

lib/librte_eal/common/eal_common_options.c

@@ -1332,6 +1332,12 @@ eal_check_common_options(struct internal_config *internal_cfg)
 			" is only supported in non-legacy memory mode\n");
 		return -1;
 	}
+	if (internal_cfg->single_file_segments &&
+			internal_cfg->hugepage_unlink) {
+		RTE_LOG(ERR, EAL, "Option --"OPT_SINGLE_FILE_SEGMENTS" is "
+			"not compatible with --"OPT_HUGE_UNLINK"\n");
+		return -1;
+	}
 
 	return 0;
 }

lib/librte_eal/linuxapp/eal/eal_memalloc.c

@@ -489,6 +489,13 @@ alloc_seg(struct rte_memseg *ms, void *addr, int socket_id,
 				__func__, strerror(errno));
 			goto resized;
 		}
+		if (internal_config.hugepage_unlink) {
+			if (unlink(path)) {
+				RTE_LOG(DEBUG, EAL, "%s(): unlink() failed: %s\n",
+					__func__, strerror(errno));
+				goto resized;
+			}
+		}
 	}
 
 	/*
@@ -587,7 +594,8 @@ alloc_seg(struct rte_memseg *ms, void *addr, int socket_id,
 		/* ignore failure, can't make it any worse */
 	} else {
 		/* only remove file if we can take out a write lock */
-		if (lock(fd, LOCK_EX) == 1)
+		if (internal_config.hugepage_unlink == 0 &&
+				lock(fd, LOCK_EX) == 1)
 			unlink(path);
 		close(fd);
 	}
@@ -612,6 +620,12 @@ free_seg(struct rte_memseg *ms, struct hugepage_info *hi,
 		return -1;
 	}
 
+	/* if we've already unlinked the page, nothing needs to be done */
+	if (internal_config.hugepage_unlink) {
+		memset(ms, 0, sizeof(*ms));
+		return 0;
+	}
+
 	/* if we are not in single file segments mode, we're going to unmap the
 	 * segment and thus drop the lock on original fd, but hugepage dir is
 	 * now locked so we can take out another one without races.