Re: [PATCH 18/23] vfs: Teach epoll to use file_hotplug_lock

[Davide Libenzi]

On Tue, 2 Jun 2009, Eric W. Biederman wrote:

> I am not clear what problem you have.
> 
> Is it the sprinkling the code that takes and removes the lock?  Just
> the VFS needs to be involved with that.  It is a slightly larger
> surface area than doing the work inside the file operations as we
> sometimes call the same method from 3-4 different places but it is
> definitely a bounded problem.
> 
> Is it putting in the handful lines per subsystem to actually use this
> functionality?  At that level something generic that is maintained
> outside of the subsystem is better than the mess we have with 4-5
> different implementations in the subsystems that need it, each having
> a different assortment of bugs.

Come on, only in the open fast path, there are at least two spin 
lock/unlock and two atomic ops. Without even starting to count all the 
extra branches and software added.
Is this stuff *really* needed, or we can faitly happily live w/out?


- Davide


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