During the realtime preemption mini-summit we discussed the entire removal of the big kernel lock. I've started working on this for some filesystems. My plan is to push the BKL down to the implementations first and remove it from there later. This series is pushing the BKL from do_new_mount() down to the filesystems. If the filesystem wasn't using the BKL at all before, it gets removed instead. If removing is trivial (e.g. because it is obviously already protected by an existing lock) it gets removed by a follow up patch in the series. Later on in the series the big kernel lock is removed from EXT2. Instead, a new lock that protects the modification of some of the superblocks fields is introduced. Version 2 of the series addressed the feedback from Matthew Wilcox and I tried to be more verbose about why I think it is safe to remove the BKL. In most cases there is no shared resource accessed anyway or the superblock s_umount rwsemaphore is used so it is trivially safe to remove the big kernel lock. Version 3 of the series addressed the feedback from Christoph Hellwig and Arnd Bergmann to not push down the BKL to filesystems that don't use it anyway. I've changed the ext2 s_lock usage in ext2_sync_super() to address Jan Kara's comments. If all affected maintainers acknowledge their parts of the patches it should get merged through one of the bkl branches in the tip tree. Jan Blunck (20): JFS: Free sbi memory in error path AFFS: Free sbi memory in error path BKL: Explicitly add BKL around get_sb/fill_super BKL: Remove outdated comment and include BKL: Remove BKL from Amiga FFS BKL: Remove BKL from BFS BKL: Remove BKL from CifsFS BKL: Remove BKL from ext3 fill_super() BKL: Remove BKL from ext3_put_super() and ext3_remount() BKL: Remove BKL from ext4 filesystem BKL: Remove BKL from exofs BKL: Remove BKL from HFS BKL: Remove BKL from HFS+ BKL: Remove BKL from JFS BKL: Remove BKL from NILFS2 BKL: Remove BKL from NTFS BKL: Remove BKL from cgroup BKL: Remove BKL from do_new_mount() ext2: Add ext2_sb_info s_lock spinlock BKL: Remove BKL from ext2 filesystem drivers/isdn/capi/capifs.c | 10 ++++++- drivers/usb/core/inode.c | 5 +++ drivers/usb/gadget/inode.c | 12 +++++++- fs/adfs/super.c | 8 +++++- fs/affs/super.c | 17 ++++-------- fs/afs/super.c | 5 +++ fs/bfs/inode.c | 8 +---- fs/cifs/cifsfs.c | 9 ++---- fs/coda/inode.c | 8 +++++- fs/ecryptfs/main.c | 4 +++ fs/exofs/super.c | 1 - fs/ext2/inode.c | 5 +-- fs/ext2/super.c | 60 ++++++++++++++++++++++++++++++-------------- fs/ext3/super.c | 12 --------- fs/ext4/super.c | 11 -------- fs/fat/namei_msdos.c | 7 ++++- fs/fat/namei_vfat.c | 7 ++++- fs/freevxfs/vxfs_super.c | 7 ++++- fs/hfs/super.c | 6 +--- fs/hfsplus/super.c | 5 --- fs/hpfs/super.c | 8 +++++- fs/isofs/inode.c | 8 +++++- fs/jffs2/super.c | 11 ++++++- fs/jfs/super.c | 23 ++++------------ fs/namespace.c | 2 - fs/ncpfs/inode.c | 8 +++++- fs/nfs/super.c | 24 +++++++++++++++++ fs/nilfs2/ioctl.c | 1 - fs/nilfs2/super.c | 10 ------- fs/ntfs/super.c | 24 +---------------- fs/ocfs2/dlm/dlmfs.c | 9 ++++++- fs/ocfs2/super.c | 5 +++ fs/qnx4/inode.c | 8 +++++- fs/reiserfs/super.c | 4 +++ fs/smbfs/inode.c | 5 +++ fs/squashfs/super.c | 6 ++++ fs/super.c | 3 -- fs/udf/super.c | 8 +++++- fs/ufs/super.c | 5 +++ include/linux/ext2_fs_sb.h | 6 ++++ kernel/cgroup.c | 4 --- 41 files changed, 234 insertions(+), 155 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
