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Date: Thu, 15 Jan 2015 14:08:42 +0000
From: Alexey Dokuchaev <danfe@FreeBSD.org>
To: Slawa Olhovchenkov <slw@zxy.spb.ru>
Subject: Re: svn commit: r277204 - head/sys/amd64/conf
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On Thu, Jan 15, 2015 at 04:53:42PM +0300, Slawa Olhovchenkov wrote:
> On Thu, Jan 15, 2015 at 01:44:46PM +0000, Alexey Dokuchaev wrote:
> > intention.  AFAIR last time we had a discussion about why our default
> > kernel is not MINIMAL, it boiled down to two main problems: 1) loader's
> > caching of disk reads (which makes loading *.ko's from /boot/loader.conf
> 
> reading large monolitic kernel is slow too.

But not nearly as slow as loading 50-60 modules at boot time (on my stable/8
I have 59 right now).  When you read one big file *once* you don't have to
worry about caching reads.  With everything moved to modules, loader does a
lot of superfluous disk access, and to remedy this we need smart(er) caching
implementation.

> /boot/loader.conf (with all modules currently present in GENERIC) may
> be instaled by bsdinstall (and may be part of base.txz).

That could be done, but not before we solve (1), and from this POV it deems
more important than (2).

> This is not only space saving.
> This is allow to [unload and load modules, change configuration in runtime
> with minimal downtime and without reboot].

I think we all know what are the benefits of modularized kernels.  But
before we solve aforementioned problems, it will remain a custom option for
advanced users.

./danfe