Messages in this thread | | | From | Ian Campbell <> | Date | Thu, 25 Aug 2005 16:07:25 +0100 | Subject | Re: dnotify/inotify and vfs questions |
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On Thu, 2005-08-25 at 15:57 +0100, Jamie Lokier wrote: > Ian Campbell wrote: > > On Tue, 2005-08-23 at 16:23 +0100, Jamie Lokier wrote: > > > <receive some request>... > > > if (any_dnotify_or_inotify_events_pending) { > > > read_dnotify_or_inotify_events(); > > > if (any_events_related_to(file)) { > > > store_in_userspace_stat_cache(file, stat(file)); > > > } > > > } > > > stat_info = lookup_userspace_stat_cache(file); > > > > > > Now that's a silly way to save one system call in the fast path by itself. > > > > I'm not that familiar with inotify internals but doesn't > > read_dnotify_or_inotify_events() or > > any_dnotify_or_inotify_events_pending() involve a syscall? > > The fast path is just any_dnotify_or_inotify_events_pending: there > aren't any relevant events pending in the fast path. [snip] > As I explained in the previous mail, all this is absolutely pointless > to save one system call. It's a lot of work for negligable gain. > > The point is when it saves lots of calls and userspace logic together, > for things like web page templates and compiled programs, which depend > on many files which can be revalidated in a small number of operations.
Thanks for the explaination.
Ian. -- Ian Campbell Current Noise: Iron Maiden - Prodigal Son
Fay: The British police force used to be run by men of integrity. Truscott: That is a mistake which has been rectified. -- Joe Orton, "Loot"
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