linux-kernel - Re: inotify, new idea?

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Message-ID: <5382D9E5.5000306@gmail.com>
Date:	Mon, 26 May 2014 08:06:29 +0200
From:	"Michael Kerrisk (man-pages)" <mtk.manpages@...il.com>
To:	Richard Weinberger <richard@....at>
CC:	mtk.manpages@...il.com,
	Lennart Sorensen <lsorense@...lub.uwaterloo.ca>,
	Jos Huisken <jos.huisken@...il.com>,
	Linux Kernel <linux-kernel@...r.kernel.org>
Subject: Re: inotify, new idea?

On 05/24/2014 02:34 PM, Richard Weinberger wrote:
> Am 24.05.2014 09:52, schrieb Michael Kerrisk (man-pages):
>> On 04/21/2014 10:42 AM, Richard Weinberger wrote:
>>> Am 21.04.2014 09:24, schrieb Michael Kerrisk:
>>>>> Does recursive monitoring even work with inotify?
>>>>> Last time I've tried it did failed as soon I did a mkdir -p a/b/c/d because
>>>>> mkdir() raced against the thread which installes the new watches.
>>>>
>>>> As I understand it, you have to program to deal with the races (rescan
>>>> directories after adding watches). I recently did a lot of work
>>>> updating the inotify(7) man page to discuss all the issues that I know
>>>> of, and their remedies. If I missed anything, I'd appreciate a note on
>>>> it, so that it can be added. See
>>>> http://man7.org/linux/man-pages/man7/inotify.7.html#NOTES
>>>
>>> I'm aware of the rescan hack, but in my case it does not help
>>> because my program must not miss any event.
>>> Currently I'm using a fuse overlay filesystem to log everything.
>>> Not perfect but works... :-)
>>
>> Richard,
>>
>> A late follow up question. How does your application deal with the
>> event overflow problem (i.e., when you get a large number of events 
>> much faster than your application can deal with them?
> 
> The downside of the FUSE approach is that you have to intercept
> every filesystem function.
> This can be a performance issue.
> But due to this design the overflow problem cannot happen as the
> FUSE filesystem blocks until the event has been proceed.

Ahh -- that clears things up for me. Thanks, Richard.

Cheers,

Michael

-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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