Re: "Read my lips: no more merges" - aka Linux 2.6.14-rc1

[Benjamin LaHaise <bcrl@kvack.org>]

On Tue, Sep 13, 2005 at 09:04:32AM +0200, Eric Dumazet wrote:
> I wish a process param could allow open() to take any free fd available, 
> not the lowest one. One can always use fcntl(fd, F_DUPFD, slot) to move a 
> fd on a specific high slot and always keep the 64 first fd slots free to 
> speedup the kernel part at open()/dup()/socket() time.

The overhead is easy to avoid by making use of dup2() and close() to keep 
the lowest file descriptors in the table free, allowing open() and socket() 
to always return 3 or 4.

Alternatively, the kernel could track available file descriptors using a 
tree to efficiently insert freed slots into an ordered list of free 
regions (something similar to the avl tree used in vmas).  Is it worth 
doing?

		-ben
-- 
"Time is what keeps everything from happening all at once." -- John Wheeler