On 04/19/2012 10:20 PM, Theodore Ts'o wrote: > As I had brought up during one of the lightning talks at the Linux > Storage and Filesystem workshop, I am interested in introducing two new > open flags, O_HOT and O_COLD. These flags are passed down to the > individual file system's inode operations' create function, and the file > system can use these flags as a hint regarding whether the file is > likely to be accessed frequently or not. > > In the future I plan to do further work on how ext4 would use these > flags, but I want to first get the ability to pass these flags plumbed > into the VFS layer and the code points for O_HOT and O_COLD reserved. > > > Theodore Ts'o (3): > fs: add new open flags O_HOT and O_COLD > fs: propagate the open_flags structure down to the low-level fs's > create() > ext4: use the O_HOT and O_COLD open flags to influence inode > allocation > I would expect that the first, and most important patch to this set would be the man page which would define the new API. What do you mean by cold/normal/hot? what is expected if supported? how can we know if supported? .... I presume you mean 3 levels (not even 2 bits) of what T10 called "read-frequency" or is that "write-frequency", or some other metrics you defined? Well in the patchset you supplied it means closer to outer-edge. What ever that means? so in the case of ext4 on SSD or DM/MD or loop or thin provisioned LUN. How do I stop it. The code is already there in Kernel and the application is setting that flag at create, how do I make the FS not do that stupid, for me, thing? I wish you'd be transparent, call it O_OUTER_DISK and be honest about it. The "undefined API" never ever worked in the past, why would it work now? And Yes an fctrl is a much better match, and with delayed allocation that should not matter, right? And one last thing. We would like to see numbers. Please show us where/how it matters. Are there down sides?. If it's so good we'd like to implement it too. Thanks Boaz > fs/9p/vfs_inode.c | 2 +- > fs/affs/affs.h | 2 +- > fs/affs/namei.c | 3 ++- > fs/bfs/dir.c | 2 +- > fs/btrfs/inode.c | 3 ++- > fs/cachefiles/namei.c | 3 ++- > fs/ceph/dir.c | 2 +- > fs/cifs/dir.c | 2 +- > fs/coda/dir.c | 3 ++- > fs/ecryptfs/inode.c | 5 +++-- > fs/exofs/namei.c | 2 +- > fs/ext2/namei.c | 4 +++- > fs/ext3/namei.c | 5 +++-- > fs/ext4/ext4.h | 8 +++++++- > fs/ext4/ialloc.c | 33 +++++++++++++++++++++++++++------ > fs/ext4/migrate.c | 2 +- > fs/ext4/namei.c | 17 ++++++++++++----- > fs/fat/namei_msdos.c | 2 +- > fs/fat/namei_vfat.c | 2 +- > fs/fcntl.c | 5 +++-- > fs/fuse/dir.c | 2 +- > fs/gfs2/inode.c | 3 ++- > fs/hfs/dir.c | 2 +- > fs/hfsplus/dir.c | 5 +++-- > fs/hostfs/hostfs_kern.c | 2 +- > fs/hugetlbfs/inode.c | 4 +++- > fs/internal.h | 6 ------ > fs/jffs2/dir.c | 5 +++-- > fs/jfs/namei.c | 2 +- > fs/logfs/dir.c | 2 +- > fs/minix/namei.c | 2 +- > fs/namei.c | 9 +++++---- > fs/ncpfs/dir.c | 5 +++-- > fs/nfs/dir.c | 6 ++++-- > fs/nfsd/vfs.c | 4 ++-- > fs/nilfs2/namei.c | 2 +- > fs/ocfs2/namei.c | 3 ++- > fs/omfs/dir.c | 2 +- > fs/ramfs/inode.c | 3 ++- > fs/reiserfs/namei.c | 5 +++-- > fs/sysv/namei.c | 4 +++- > fs/ubifs/dir.c | 2 +- > fs/udf/namei.c | 2 +- > fs/ufs/namei.c | 2 +- > fs/xfs/xfs_iops.c | 3 ++- > include/asm-generic/fcntl.h | 7 +++++++ > include/linux/fs.h | 14 ++++++++++++-- > ipc/mqueue.c | 2 +- > 48 files changed, 143 insertions(+), 74 deletions(-) > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
