From 093316a897a2eb4972a7a3a5888f40975d03f6bf Mon Sep 17 00:00:00 2001 From: Brice Goglin Date: Tue, 5 Apr 2022 17:39:50 +0200 Subject: [PATCH] linux: (partial) fix the discovery of hugepages on btrfs fsroot btrfs always returns 1 in directory stat.st_nlink. It breaks make check in tests/linux/ because the hugepages discovery uses st_nlink to allocate the memory page_types array. Always allocate at least 3 page_types slots (enough for all known cases, 1 for normal, 2 for huge pages) (partially cherry-picked from commit 7f351cec9bfe54a031f35ad16c9cfb99784d76dc) We don't reallocate later if needed as in 2.x commit 7f351cec9bfe54a031f35ad16c9cfb99784d76dc because v1.11 doesn't deserve a complete fix. Just commit the minimal change so that tests/linux/2i386-2t-hugepagesizecount with HWLOC_PAGESIZE_DEBUG=4096 doesn't crash in btrfs anymore (test-topology.sh fails during make check if /tmp is in btrfs). Thanks to Philippe Swartvagher for the report. Signed-off-by: Brice Goglin --- src/topology-linux.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/src/topology-linux.c b/src/topology-linux.c index 58c275fea..269eca7f5 100644 --- a/src/topology-linux.c +++ b/src/topology-linux.c @@ -1,6 +1,6 @@ /* * Copyright © 2009 CNRS - * Copyright © 2009-2019 Inria. All rights reserved. + * Copyright © 2009-2022 Inria. All rights reserved. * Copyright © 2009-2013, 2015 Université Bordeaux * Copyright © 2009-2014 Cisco Systems, Inc. All rights reserved. * Copyright © 2015 Intel, Inc. All rights reserved. @@ -2329,7 +2329,14 @@ hwloc_get_procfs_meminfo_info(struct hwloc_topology *topology, err = hwloc_stat("/sys/kernel/mm/hugepages", &st, data->root_fd); if (!err) { - types = 1 + st.st_nlink-2; + types = 1 /* normal non-huge size */ + st.st_nlink - 2 /* ignore . and .. */; + if (types < 3) + /* some buggy filesystems (e.g. btrfs when reading from fsroot) + * return wrong st_nlink for directories (always 1 for btrfs). + * use 3 as a sane default (default page + 2 huge sizes). + * hwloc_parse_hugepages_info() will extend it if needed. + */ + types = 3; has_sysfs_hugepages = 1; }