diff options
Diffstat (limited to 'fs/btrfs/super.c')
| -rw-r--r-- | fs/btrfs/super.c | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 08d33cb372fb..98fa0f382480 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -28,6 +28,7 @@ #include <linux/btrfs.h> #include <linux/security.h> #include <linux/fs_parser.h> +#include <linux/swap.h> #include "messages.h" #include "delayed-inode.h" #include "ctree.h" @@ -683,8 +684,11 @@ bool btrfs_check_options(const struct btrfs_fs_info *info, ret = false; if (!test_bit(BTRFS_FS_STATE_REMOUNTING, &info->fs_state)) { - if (btrfs_raw_test_opt(*mount_opt, SPACE_CACHE)) + if (btrfs_raw_test_opt(*mount_opt, SPACE_CACHE)) { btrfs_info(info, "disk space caching is enabled"); + btrfs_warn(info, +"space cache v1 is being deprecated and will be removed in a future release, please use -o space_cache=v2"); + } if (btrfs_raw_test_opt(*mount_opt, FREE_SPACE_TREE)) btrfs_info(info, "using free-space-tree"); } @@ -2398,7 +2402,13 @@ static long btrfs_nr_cached_objects(struct super_block *sb, struct shrink_contro trace_btrfs_extent_map_shrinker_count(fs_info, nr); - return nr; + /* + * Only report the real number for DEBUG builds, as there are reports of + * serious performance degradation caused by too frequent shrinks. + */ + if (IS_ENABLED(CONFIG_BTRFS_DEBUG)) + return nr; + return 0; } static long btrfs_free_cached_objects(struct super_block *sb, struct shrink_control *sc) @@ -2406,6 +2416,15 @@ static long btrfs_free_cached_objects(struct super_block *sb, struct shrink_cont const long nr_to_scan = min_t(unsigned long, LONG_MAX, sc->nr_to_scan); struct btrfs_fs_info *fs_info = btrfs_sb(sb); + /* + * We may be called from any task trying to allocate memory and we don't + * want to slow it down with scanning and dropping extent maps. It would + * also cause heavy lock contention if many tasks concurrently enter + * here. Therefore only allow kswapd tasks to scan and drop extent maps. + */ + if (!current_is_kswapd()) + return 0; + return btrfs_free_extent_maps(fs_info, nr_to_scan); } |