Extent tree status asking

Hi Allison,

Currently I am trying to reduce the lock contention of direct I/O in ext4 because it is a bottleneck. A trivial idea is that a new fucntion is defined to replace the generic_file_aio_write, which do some write operations with acquiring i_data_sem lock in inode.

I know that you are trying to implement extent tree, and I have seen your patch set '[PATCH] Rename delayed extents to status extents'. After extent tree is made, the implementation of direct I/O without i_mutex and range lock is straightforward and it is better than my trivial idea. I think that maybe I can borrow you works. So could you please share me your schedule and/or other information?

Last month on ext4 workshop, we discuss the extent tree, range lock and I/O tree. Obviously, I/O tree is used to store I/O operations, which can track delay allocation, do unwritten->written conversion and implement range lock. It is very useful for ext4 and I am interested in this proposal. I know that you have begun to do some works. So would you like to tell me the status of extent tree? I don't know whether or not there has some things that I can be involved. If you have some advices or there is something that I can help, please let me know. Thank you and looking forward your reply.

Regards,
Zheng

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Quoted 23 lines · Zheng Liu

Hi Allison,

Currently I am trying to reduce the lock contention of direct I/O in ext4 because it is a bottleneck. A trivial idea is that a new fucntion is defined to replace the generic_file_aio_write, which do some write operations with acquiring i_data_sem lock in inode.

I know that you are trying to implement extent tree, and I have seen your patch set '[PATCH] Rename delayed extents to status extents'. After extent tree is made, the implementation of direct I/O without i_mutex and range lock is straightforward and it is better than my trivial idea. I think that maybe I can borrow you works. So could you please share me your schedule and/or other information?

Last month on ext4 workshop, we discuss the extent tree, range lock and I/O tree. Obviously, I/O tree is used to store I/O operations, which can track delay allocation, do unwritten->written conversion and implement range lock. It is very useful for ext4 and I am interested in this proposal. I know that you have begun to do some works. So would you like to tell me the status of extent tree? I don't know whether or not there has some things that I can be involved. If you have some advices or there is something that I can help, please let me know. Thank you and looking forward your reply.

Quoted 2 lines

Regards,
Zheng

Hi Zheng,

Well, I can share with you what I have done so far with Yongqiang's delayed extent tree, but since I was moved to the ganesha project, extent locks are no longer a business priority now. I've done some work on it on my own time, but I have not been able to keep up pace with it. If someone else has the hours to push it faster than I can at this point, I would certainly be understanding of that.

Basically though the plan was to modify Yongqiang's delayed extent tree to track allocated extents as well as delayed extents. And then add the extent locks on top of that once that's working. My idea was to add a type member to the extents so that we have have "delayed" "allocated" and "hole" extents. I've renamed the delayed extent scheme to "status extents" because it seemed more appropriate. That part I can send out, but I was still in the middle of coding and debugging allocated extents and extent locks. Because the tree was originally written to merge things as much as possible, there is some rewrite that is needed. I was working on making the add and remove routines more like "type replace" routines sense once the extent is locked, we can really only change the type, and we cannot merge dissimilar types or extents locked by other processes. I hope that makes sense, please let me know if you need more clarification. I will send out the status extent set, sense that part is stable.

Quoted 36 lines · Allison Henderson

Quoted 23 lines · Zheng Liu

Hi Allison,

Currently I am trying to reduce the lock contention of direct I/O in ext4 because it is a bottleneck. A trivial idea is that a new fucntion is defined to replace the generic_file_aio_write, which do some write operations with acquiring i_data_sem lock in inode.

I know that you are trying to implement extent tree, and I have seen your patch set '[PATCH] Rename delayed extents to status extents'. After extent tree is made, the implementation of direct I/O without i_mutex and range lock is straightforward and it is better than my trivial idea. I think that maybe I can borrow you works. So could you please share me your schedule and/or other information?

Last month on ext4 workshop, we discuss the extent tree, range lock and I/O tree. Obviously, I/O tree is used to store I/O operations, which can track delay allocation, do unwritten->written conversion and implement range lock. It is very useful for ext4 and I am interested in this proposal. I know that you have begun to do some works. So would you like to tell me the status of extent tree? I don't know whether or not there has some things that I can be involved. If you have some advices or there is something that I can help, please let me know. Thank you and looking forward your reply.

Quoted 2 lines

Regards,
Zheng

Hi Zheng,

Well, I can share with you what I have done so far with Yongqiang's delayed extent tree, but since I was moved to the ganesha project, extent locks are no longer a business priority now. I've done some work on it on my own time, but I have not been able to keep up pace with it. If someone else has the hours to push it faster than I can at this point, I would certainly be understanding of that.

Quoted 16 lines

Basically though the plan was to modify Yongqiang's delayed extent tree to track allocated extents as well as delayed extents. And then add the extent locks on top of that once that's working. My idea was to add a type member to the extents so that we have have "delayed" "allocated" and "hole" extents. I've renamed the delayed extent scheme to "status extents" because it seemed more appropriate. That part I can send out, but I was still in the middle of coding and debugging allocated extents and extent locks. Because the tree was originally written to merge things as much as possible, there is some rewrite that is needed. I was working on making the add and remove routines more like "type replace" routines sense once the extent is locked, we can really only change the type, and we cannot merge dissimilar types or extents locked by other processes. I hope that makes sense, please let me know if you need more clarification. I will send out the status extent set, sense that part is stable.

Thank you for sharing with me. I am willing to take this work because my employee provides me a full time to finish this work. I see that you have sent the patch set to the mailing list. I will pick it and go on working. Thanks again. :)

Regards,
Zheng