On 19/9/17 18:32, Ritesh Harjani wrote: > Hello, > > This patch series is based on the upstream discussion with Jan > & Joseph @ [1]. > It is based on top of Matthew's v3 ext4 iomap patch series [2] > > Patch-1: Adds the ext4_ilock/unlock APIs and also replaces all > inode_lock/unlock instances from fs/ext4/* > > For now I already accounted for trylock/lock issue symantics > (which was discussed here [3]) in the same patch, > since the this whole patch was around inode_lock/unlock API, > so I thought it will be best to address that issue in the same patch. > However, kindly let me know if otherwise. > > Patch-2: Commit msg of this patch describes in detail about > what it is doing. > In brief - we try to first take the shared lock (instead of exclusive > lock), unless it is a unaligned_io or extend_io. Then in > ext4_dio_write_checks(), if we start with shared lock, we see > if we can really continue with shared lock or not. If not, then > we release the shared lock then acquire exclusive lock > and restart ext4_dio_write_checks(). > > > Tested against few xfstests (with dioread_nolock mount option), > those ran fine (ext4 & generic). > > I tried testing performance numbers on my VM (since I could not get > hold of any real h/w based test device). I could test the fact > that earlier we were trying to do downgrade_write() lock, but with > this patch, that path is now avoided for fio test case > (as reported by Joseph in [4]). > But for the actual results, I am not sure if VM machine testing could > really give the reliable perf numbers which we want to take a look at. > Though I do observe some form of perf improvements, but I could not > get any reliable numbers (not even with the same list of with/without > patches with which Joseph posted his numbers [1]). > > > @Joseph, > Would it be possible for you to give your test case a run with this > patches? That will be really helpful. > Sure, will post the result ASAP. Thanks, Joseph > Branch for this is hosted at below tree. > > https://github.com/riteshharjani/linux/tree/ext4-ilock-RFC > > [1]: https://lore.kernel.org/linux-ext4/20190910215720.GA7561@xxxxxxxxxxxxxx/ > [2]: https://lwn.net/Articles/799184/ > [3]: https://lore.kernel.org/linux-fsdevel/20190911103117.E32C34C044@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ > [4]: https://lore.kernel.org/linux-ext4/1566871552-60946-4-git-send-email-joseph.qi@xxxxxxxxxxxxxxxxx/ > > > Ritesh Harjani (2): > ext4: Add ext4_ilock & ext4_iunlock API > ext4: Improve DIO writes locking sequence > > fs/ext4/ext4.h | 33 ++++++ > fs/ext4/extents.c | 16 +-- > fs/ext4/file.c | 253 ++++++++++++++++++++++++++++++++-------------- > fs/ext4/inode.c | 4 +- > fs/ext4/ioctl.c | 16 +-- > fs/ext4/super.c | 12 +-- > fs/ext4/xattr.c | 16 +-- > 7 files changed, 244 insertions(+), 106 deletions(-) >
