From: Pavel Machek <pavel@ucw.cz>
To: Patrick Mochel <mochel@osdl.org>
Cc: Nigel Cunningham <ncunningham@clear.net.nz>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: SWSUSP Discontiguous pagedir patch
Date: Mon, 10 Mar 2003 20:23:00 +0100 [thread overview]
Message-ID: <20030310192300.GC11310@atrey.karlin.mff.cuni.cz> (raw)
In-Reply-To: <Pine.LNX.4.33.0303101012230.1002-100000@localhost.localdomain>
Hi!
> > But your solution would also only support *one* suspend partition,
> > right? (And patches for using more than one swap partition are
> > available for 2.4.X; I don't like them due to added complexity).
>
> Having a dedicated partition has an advantage in just that - it's
> dedicated to saving system state. Users must consciously create it, and
> must make it as big as the size of memory they have (or will have). Plus,
> it's not tied to the amount of memory being used when you suspend.
That's a problem. Users do not have suspend partitions, but they do
have swap partition. And repartitioning existing installation is very
painfull. OTOH it is true that if we want
"emergency-suspend-to-disk-when-battery-low", dedicated partition
makes some sense.... ... Well. You can always do swapoff, swapon,
swsusp. Maybe some processes will die, but that's life ;-).
[But for that you'd have to guarantee that suspend always works, which
is hard, anyway.]
> Swap space has a specific purpose, I see it as a detriment to overload its
> intended usage. Of couse, that's just my opinion, and I don't have code to
> back it up.
Well, I see it as advantage because I have swap space anyway (rarely
really used), so why not reuse it for swsusp?
> > It is pretty magical operation, so you are at least warned. [And this has
> > nothing to do with fact we suspend-to-swap].
>
> IMO, warnings should be conveyed in comments, not in cryptic function
> names. Besides, there is nothing magical about it, unless that sequence of
> instructions actually does make your computer glow, levitate, or turn into
> a mermaid. In which case, I would like to know where I can find one. ;)
:-). Well, comments were getting out of date because code was in
permanent flux. It makes sense to comment it now.
> > Your solution will not work if your suspend partition is not there.
>
> I didn't mean to sound like a hypocrit, I apologize. The advantage of
> using a dedicated partition over swap is that in order to create the
> partition, the user must make a conscious decision to do so.
>
> There are parameters that can be enforced when making the partition, like
> the size and its existence on a persistant medium. These can be enforced
> by a user making a swap partition, but it places extra burden on the user.
Well, IMO checklist like:
if you want to use swsusp you have to
a) check swap is on persistent medium
b) make sure swap is at least as big as memory/2 [not really
neccessary, we might be lucky and swsusp with 30MB of swap...]
is easier for the user than repartitioning their harddrives. [I'd like
to see someone running swap on floppy ;-)]
> > So you don't really want to create separate "suspend partition"? Good.
>
> Sorry, the patch included a few distinct things, and I should have made it
> a bit more clear. In includes:
>
> - A generic PM framework which PM drivers can register with.
>
> Users can specificy which handler they wish to use for different states,
> based on their preference or the capabilities of their systems.
>
> They can also use one mechanism for entering power states:
> /sys/power/power_state, instead of relying different mechanisms for
> different PM drivers (/proc/acpi/sleep vs. apm(1)
> vs. sys_reboot()).
I believe sys_reboot() is the right way to do
that. /sys/power/... needs sysfs mounted etc. /proc/acpi/sleep just
happened to already be there and be very convenient.
> In the long run, I'd like to develop a solution using a dedicated
> partition. But, that wouldn't necessarily obviate the use of swsusp. It
> would coexist alongside it.
Actually "dedicated partition" vs. "swap partition" is quite a small
detail. It only affects disk allocation routines. Basic stuff like
"atomic copy" stays the same...
> > > I understand you may not a rewrite of swsusp (regardless of how much
> > > cleaner the code is), and I respect that. I'm completely willing to leave
> > > kernel/suspend.c intact, and let you work in the integration into the
> > > generic PM model, and/or simply rename the new code something like
> > > swsusp2, swsusp-XP, or swsusp-pat. ;)
> >
> > So you want to develop swsusp-pat that will suspend to partition,
> > allow another kernel version, and you think you can suspend when 90%
> > of your memory is kmalloc()-ed? Do you agree that separate disk
> > drivers for suspend is bad idea?
>
> Yes.
Do you think you can suspend with 90% memory kmalloc()-ed?
Pavel
--
Horseback riding is like software...
...vgf orggre jura vgf serr.
next prev parent reply other threads:[~2003-03-10 19:12 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1045784829.3821.10.camel@laptop-linux.cunninghams>
[not found] ` <20030223223757.GA120@elf.ucw.cz>
[not found] ` <1046136752.1784.15.camel@laptop-linux.cunninghams>
[not found] ` <20030227132024.GB27084@atrey.karlin.mff.cuni.cz>
2003-02-27 18:42 ` SWSUSP Discontiguous pagedirs Nigel Cunningham
2003-03-01 4:22 ` SWSUSP Discontiguous pagedir patch Nigel Cunningham
2003-03-02 23:55 ` Patrick Mochel
2003-03-03 2:06 ` Nigel Cunningham
2003-03-03 2:31 ` Nigel Cunningham
2003-03-03 12:30 ` Pavel Machek
2003-03-04 20:36 ` Patrick Mochel
2003-03-05 20:50 ` Pavel Machek
2003-03-05 21:52 ` Linux vs Windows temperature anomaly Jonathan Lundell
2003-03-05 23:11 ` Herman Oosthuysen
2003-03-05 23:38 ` Con Kolivas
2003-03-05 23:50 ` Russell King
2003-03-06 0:29 ` Ed Sweetman
2003-03-06 0:47 ` Trever L. Adams
2003-03-06 9:45 ` Russell King
2003-03-06 1:58 ` Jonathan Lundell
2003-03-06 7:18 ` Corvus Corax
2003-03-06 7:57 ` Ed Sweetman
2003-03-06 8:18 ` Corvus Corax
2003-03-06 8:58 ` Ed Sweetman
2003-03-06 15:41 ` Jesse Pollard
2003-03-06 14:27 ` Jesse Pollard
2003-03-06 2:57 ` David Rees
2003-03-06 6:12 ` Matthias Schniedermeyer
2003-03-06 16:07 ` Jonathan Lundell
2003-03-07 0:40 ` Horst von Brand
2003-03-05 18:02 ` SWSUSP Discontiguous pagedir patch Pavel Machek
2003-03-07 17:14 ` Patrick Mochel
2003-03-07 20:27 ` Pavel Machek
2003-03-09 19:39 ` Benjamin Herrenschmidt
2003-03-09 20:12 ` Pavel Machek
2003-03-10 16:49 ` Patrick Mochel
2003-03-10 19:23 ` Pavel Machek [this message]
2003-03-10 19:05 ` Patrick Mochel
2003-03-10 22:17 ` Nigel Cunningham
2003-03-10 23:20 ` Pavel Machek
2003-03-07 20:36 ` Pavel Machek
2003-03-10 16:51 ` Patrick Mochel
2003-03-10 19:12 ` Pavel Machek
2003-03-10 18:59 ` Patrick Mochel
2003-03-07 20:41 ` Pavel Machek
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20030310192300.GC11310@atrey.karlin.mff.cuni.cz \
--to=pavel@ucw.cz \
--cc=linux-kernel@vger.kernel.org \
--cc=mochel@osdl.org \
--cc=ncunningham@clear.net.nz \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).