diff options
Diffstat (limited to 'fs/xfs/xfs_mount.c')
| -rw-r--r-- | fs/xfs/xfs_mount.c | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c index d5dcf9869860..bbb7c4f05b21 100644 --- a/fs/xfs/xfs_mount.c +++ b/fs/xfs/xfs_mount.c @@ -1374,3 +1374,42 @@ xfs_mod_delalloc( percpu_counter_add_batch(&mp->m_delalloc_blks, delta, XFS_DELALLOC_BATCH); } + +/* + * Estimate the amount of parallelism that is available for metadata operations + * on this filesystem. + */ +unsigned int +xfs_guess_metadata_threads( + struct xfs_mount *mp) +{ + unsigned int threads; + + /* + * Estimate the amount of parallelism for metadata operations from the + * least capable of the two devices that handle metadata. Cap that + * estimate to the number of AGs to avoid unnecessary lock contention. + */ + threads = xfs_buftarg_guess_threads(mp->m_ddev_targp); + if (mp->m_logdev_targp != mp->m_ddev_targp) + threads = min(xfs_buftarg_guess_threads(mp->m_logdev_targp), + threads); + threads = min(mp->m_sb.sb_agcount, threads); + + /* If the storage told us it has fancy capabilities, we're done. */ + if (threads > 1) + goto clamp; + + /* + * Metadata storage did not even hint that it has any parallel + * capability. If the filesystem was formatted with a stripe unit and + * width, we'll treat that as evidence of a RAID setup and estimate + * the number of disks. + */ + if (mp->m_sb.sb_unit > 0 && mp->m_sb.sb_width > mp->m_sb.sb_unit) + threads = mp->m_sb.sb_width / mp->m_sb.sb_unit; + +clamp: + /* Don't return an estimate larger than the CPU count. */ + return min(num_online_cpus(), threads); +} |