From 97e728d4353f38c87bf0804cdfd79a9b13fc2c3e Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Tue, 21 Apr 2009 17:40:57 -0400 Subject: Btrfs: try to keep a healthy ratio of metadata vs data block groups This patch makes the chunk allocator keep a good ratio of metadata vs data block groups. By default for every 8 data block groups, we'll allocate 1 metadata chunk, or about 12% of the disk will be allocated for metadata. This can be changed by specifying the metadata_ratio mount option. This is simply the number of data block groups that have to be allocated to force a metadata chunk allocation. By making sure we allocate metadata chunks more often, we are less likely to get into situations where the whole disk has been allocated as data block groups. Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/super.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'fs/btrfs/super.c') diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 9744af9d71e..30c9a8ca2a5 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -68,7 +68,7 @@ enum { Opt_degraded, Opt_subvol, Opt_device, Opt_nodatasum, Opt_nodatacow, Opt_max_extent, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd, Opt_thread_pool, Opt_noacl, Opt_compress, Opt_notreelog, - Opt_flushoncommit, Opt_err, + Opt_ratio, Opt_flushoncommit, Opt_err, }; static match_table_t tokens = { @@ -87,6 +87,7 @@ static match_table_t tokens = { {Opt_noacl, "noacl"}, {Opt_notreelog, "notreelog"}, {Opt_flushoncommit, "flushoncommit"}, + {Opt_ratio, "metadata_ratio=%d"}, {Opt_err, NULL}, }; @@ -234,6 +235,15 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) printk(KERN_INFO "btrfs: turning on flush-on-commit\n"); btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT); break; + case Opt_ratio: + intarg = 0; + match_int(&args[0], &intarg); + if (intarg) { + info->metadata_ratio = intarg; + printk(KERN_INFO "btrfs: metadata ratio %d\n", + info->metadata_ratio); + } + break; default: break; } -- cgit v1.2.3