[Gluster-devel] [RFC] various lists on inode table usage?

[Changwei Ge]

Hi Amar,

Thank you very much for your quick reply :-)

On 2019/10/21 2:44 下午, Amar Tumballi wrote:
> 
> 
> On Mon, Oct 21, 2019 at 11:58 AM Changwei Ge <chge at linux.alibaba.com 
> <mailto:chge at linux.alibaba.com>> wrote:
> 
>     Hi,
> 
>     I am recently working on optimizing inode searching/getting/putting
>     concurrency. Before the experiment/trial goes, I would like to get
>     fully
>     understand what the usage of several lists of inode table, especially
>     for 'invalidate list', since the major difficulty making inode
>     searching
>     run concurrently is that We have to move inode from one list to the
>     other and modify some attributes against inode table.
>     After reading corresponding code, it seems that inode table 'invalidate
>     list' is only retrieved when destroying inode
>     table(inode_table_destroy).
> 
>     Can someone help explain the list usage/purpose of 'invalidate list'?
> 
> 
> 'invalidate_list' is used only in client side. The patch which got it is 
> below:
> 
> https://github.com/gluster/glusterfs/commit/d49b41e817d592c1904b6f01716df6546dad3ebe 
> 
> 
> Hope this gives some idea.

Cool, this helps me to understand more deeply on inode table.
I will check out other related commits as well.

> 
> Happy to help. If there is an interest, we can even have a video 
> conference for all interested developers to discuss inode table, and 
> detail out how it is done.
> 

Ack.
As I think that inode table(how we manage inode/dentry) is one of the 
most critical parts of a certain type of FS, we should consider and 
design carefully hence run it efficiently.
What I can see from glusterfs HEAD code is that we might have many 
locking contentions and burden too much logic into inode_[un]ref().

So how can we arrange a video conference and have a further discussion?

Thanks,
Changwei

> For getting complete history of changes to inode.c (from 
> https://github.com/amarts/glusterfs/commit/72db44413ce4686b465c29ea8383fa4f09f53a76), 
> you can clone github.com/amarts/glusterfs 
> <http://github.com/amarts/glusterfs> and see that over time what changes 
> got into the file... 'git log libglusterfs/src/inode.c' gives an idea.
> 
> Regards,
> Amar
> 
> 
> 
>     Thanks,
>     Changwei
>