Re: [take21 0/4] kevent: Generic event handling mechanism.

From: Jeff Garzik
Date: Tue Nov 07 2006 - 07:32:53 EST


Evgeniy Polyakov wrote:
Mmap ring buffer implementation was stopped by Andrew Morton and Ulrich
Drepper, process' memory is used instead. copy_to_user() is slower (and
some times noticebly), but there are major advantages of such approach.


hmmmm. I say there are advantages to both.

Perhaps create a "kevent_direct_limit" resource limit for each thread. By default, each thread could mmap $n pinned pagecache pages. Sysadmin can tune certain app resource limits to permit more.

I would think that retaining the option to avoid copy_to_user() -somehow- in -some- cases would be wise.

Jeff


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