Re: tail: use polling and inotify for mixed remote/local arguments?

[Bernhard Voelker]

On 01/04/2012 09:46 AM, Jim Meyering wrote:
> Bernhard Voelker wrote:
>> I stumbled over this readme sentence:
>>
>>> tail -f now uses polling (not inotify) when any of its file arguments
>>> resides on a file system of unknown type.
>>
>> So I asked myself what happens if all file system types of all arguments
>> are known but one is "remote"? strace gave the answer: in that case,
>> tail uses polling for all arguments although it could use inotify for
>> at least some of them.
>>
>> Is there a technical reason to do so, or is this just because the
>> implementation would be more complicated?
> 
> The implementation would be more complicated.
> 
> However, as I wrote recently regarding distributed file systems,
> tail -f may end up doing something smarter to accommodate them.
> It could use inotify to handle local modifications, and polling
> to catch changes that do not trigger inotify events.

Thanks for the clarification.

> But even that feels like a tough call, unless the hybrid code
> can somehow be very clean and simple.  Would be the benefit even
> be perceptible?  To how many people?  How often do people run tail -f
> on a combination of local and non-local files?

I agree.

Have a nice day,
Berny