On Thu, Aug 01, 2019 at 12:17:50PM +1000, Dave Chinner wrote: > From: Dave Chinner <dchinner@xxxxxxxxxx> > > Now that we don't do IO from the inode reclaim code, there is no > need to optimise inode scanning order for optimal IO > characteristics. The AIL takes care of that for us, so now reclaim > can focus on selecting the best inodes to reclaim. > > Hence we can change the inode reclaim algorithm to a real LRU and > remove the need to use the radix tree to track and walk inodes under > reclaim. This frees up a radix tree bit and simplifies the code that > marks inodes are reclaim candidates. It also simplifies the reclaim > code - we don't need batching anymore and all the reclaim logic > can be added to the LRU isolation callback. > > Further, we get node aware reclaim at the xfs_inode level, which > should help the per-node reclaim code free relevant inodes faster. > > We can re-use the VFS inode lru pointers - once the inode has been > reclaimed from the VFS, we can use these pointers ourselves. Hence > we don't need to grow the inode to change the way we index > reclaimable inodes. > > Start by adding the list_lru tracking in parallel with the existing > reclaim code. This makes it easier to see the LRU infrastructure > separate to the reclaim algorithm changes. Especially the locking > order, which is ip->i_flags_lock -> list_lru lock. > > Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx> > --- > fs/xfs/xfs_icache.c | 31 +++++++------------------------ > fs/xfs/xfs_icache.h | 1 - > fs/xfs/xfs_mount.h | 1 + > fs/xfs/xfs_super.c | 31 ++++++++++++++++++++++++------- > 4 files changed, 32 insertions(+), 32 deletions(-) > ... > diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c > index a59d3a21be5c..b5c4c1b6fd19 100644 > --- a/fs/xfs/xfs_super.c > +++ b/fs/xfs/xfs_super.c ... > @@ -1801,7 +1817,8 @@ xfs_fs_nr_cached_objects( > /* Paranoia: catch incorrect calls during mount setup or teardown */ > if (WARN_ON_ONCE(!sb->s_fs_info)) > return 0; > - return xfs_reclaim_inodes_count(XFS_M(sb)); > + > + return list_lru_shrink_count(&XFS_M(sb)->m_inode_lru, sc); Do we not need locking here, or are we just skipping it because this apparently maintains a count field and accuracy isn't critical? If the latter, a one liner comment would be useful. Brian > } > > static long > -- > 2.22.0 >
