From: Andrew Morton <akpm@linux-foundation.org>
To: Minchan Kim <minchan@kernel.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Dan Magenheimer <dan.magenheimer@oracle.com>,
Sonny Rao <sonnyrao@google.com>, Bryan Freed <bfreed@google.com>,
Hugh Dickins <hughd@google.com>, Rik van Riel <riel@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCH 2/2] mm: forcely swapout when we are out of page cache
Date: Tue, 15 Jan 2013 16:09:57 -0800 [thread overview]
Message-ID: <20130115160957.9ef860d7.akpm@linux-foundation.org> (raw)
In-Reply-To: <20130111044327.GB6183@blaptop>
On Fri, 11 Jan 2013 13:43:27 +0900
Minchan Kim <minchan@kernel.org> wrote:
> Hi Andrew,
>
> On Thu, Jan 10, 2013 at 01:58:28PM -0800, Andrew Morton wrote:
> > On Thu, 10 Jan 2013 11:23:06 +0900
> > Minchan Kim <minchan@kernel.org> wrote:
> >
> > > > I have a feeling that laptop mode has bitrotted and these patches are
> > > > kinda hacking around as-yet-not-understood failures...
> > >
> > > Absolutely, this patch is last guard for unexpectable behavior.
> > > As I mentioned in cover-letter, Luigi's problem could be solved either [1/2]
> > > or [2/2] but I wanted to add this as last resort in case of unexpected
> > > emergency. But you're right. It's not good to hide the problem like this path
> > > so let's drop [2/2].
> > >
> > > Also, I absolutely agree it has bitrotted so for correcting it, we need a
> > > volunteer who have to inverstigate power saveing experiment with long time.
> > > So [1/2] would be band-aid until that.
> >
> > I'm inclined to hold off on 1/2 as well, really.
>
> Then, what's your plan?
My plan is to sit here until someone gets down and fully tests and
fixes laptop-mode. Making it work properly, reliably and as-designed.
Or perhaps someone wants to make the case that we just don't need it
any more (SSDs are silent!) and removes it all.
> >
> > The point of laptop_mode isn't to save power btw - it is to minimise
> > the frequency with which the disk drive is spun up. By deferring and
> > then batching writeout operations, basically.
>
> I don't get it. Why should we minimise such frequency?
Because my laptop was going clickety every minute and was keeping me
awake.
> It's for saving the power to increase batter life.
It might well have that effect, dunno. That wasn't my intent. Testing
needed!
> As I real all document about laptop_mode, they all said about the power
> or battery life saving.
>
> 1. Documentation/laptops/laptop-mode.txt
> 2. http://linux.die.net/man/8/laptop_mode
> 3. http://samwel.tk/laptop_mode/
> 3. http://www.thinkwiki.org/wiki/Laptop-mode
Documentation creep ;)
Ten years ago, gad: http://lwn.net/Articles/1652/
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: Minchan Kim <minchan@kernel.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Dan Magenheimer <dan.magenheimer@oracle.com>,
Sonny Rao <sonnyrao@google.com>, Bryan Freed <bfreed@google.com>,
Hugh Dickins <hughd@google.com>, Rik van Riel <riel@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCH 2/2] mm: forcely swapout when we are out of page cache
Date: Tue, 15 Jan 2013 16:09:57 -0800 [thread overview]
Message-ID: <20130115160957.9ef860d7.akpm@linux-foundation.org> (raw)
In-Reply-To: <20130111044327.GB6183@blaptop>
On Fri, 11 Jan 2013 13:43:27 +0900
Minchan Kim <minchan@kernel.org> wrote:
> Hi Andrew,
>
> On Thu, Jan 10, 2013 at 01:58:28PM -0800, Andrew Morton wrote:
> > On Thu, 10 Jan 2013 11:23:06 +0900
> > Minchan Kim <minchan@kernel.org> wrote:
> >
> > > > I have a feeling that laptop mode has bitrotted and these patches are
> > > > kinda hacking around as-yet-not-understood failures...
> > >
> > > Absolutely, this patch is last guard for unexpectable behavior.
> > > As I mentioned in cover-letter, Luigi's problem could be solved either [1/2]
> > > or [2/2] but I wanted to add this as last resort in case of unexpected
> > > emergency. But you're right. It's not good to hide the problem like this path
> > > so let's drop [2/2].
> > >
> > > Also, I absolutely agree it has bitrotted so for correcting it, we need a
> > > volunteer who have to inverstigate power saveing experiment with long time.
> > > So [1/2] would be band-aid until that.
> >
> > I'm inclined to hold off on 1/2 as well, really.
>
> Then, what's your plan?
My plan is to sit here until someone gets down and fully tests and
fixes laptop-mode. Making it work properly, reliably and as-designed.
Or perhaps someone wants to make the case that we just don't need it
any more (SSDs are silent!) and removes it all.
> >
> > The point of laptop_mode isn't to save power btw - it is to minimise
> > the frequency with which the disk drive is spun up. By deferring and
> > then batching writeout operations, basically.
>
> I don't get it. Why should we minimise such frequency?
Because my laptop was going clickety every minute and was keeping me
awake.
> It's for saving the power to increase batter life.
It might well have that effect, dunno. That wasn't my intent. Testing
needed!
> As I real all document about laptop_mode, they all said about the power
> or battery life saving.
>
> 1. Documentation/laptops/laptop-mode.txt
> 2. http://linux.die.net/man/8/laptop_mode
> 3. http://samwel.tk/laptop_mode/
> 3. http://www.thinkwiki.org/wiki/Laptop-mode
Documentation creep ;)
Ten years ago, gad: http://lwn.net/Articles/1652/
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next prev parent reply other threads:[~2013-01-16 0:10 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-09 6:21 [PATCH 0/2] Use up free swap space before reaching OOM kill Minchan Kim
2013-01-09 6:21 ` [PATCH 1/2] mm: prevent to add a page to swap if may_writepage is unset Minchan Kim
2013-01-09 6:21 ` Minchan Kim
2013-01-09 6:56 ` Johannes Weiner
2013-01-09 6:56 ` Johannes Weiner
2013-01-09 7:10 ` Minchan Kim
2013-01-09 7:10 ` Minchan Kim
2013-01-10 0:18 ` Andrew Morton
2013-01-10 0:18 ` Andrew Morton
2013-01-10 2:03 ` Minchan Kim
2013-01-10 2:03 ` Minchan Kim
2013-01-10 23:24 ` Luigi Semenzato
2013-01-10 23:27 ` Luigi Semenzato
2013-01-10 23:27 ` Luigi Semenzato
2013-01-11 4:03 ` Minchan Kim
2013-01-11 4:03 ` Minchan Kim
2013-01-10 0:20 ` Andrew Morton
2013-01-10 0:20 ` Andrew Morton
2013-01-16 21:41 ` Andrew Morton
2013-01-16 21:41 ` Andrew Morton
2013-01-17 0:53 ` Minchan Kim
2013-01-17 0:53 ` Minchan Kim
2013-01-17 22:22 ` Andrew Morton
2013-01-17 22:22 ` Andrew Morton
2013-01-17 23:36 ` Minchan Kim
2013-01-17 23:36 ` Minchan Kim
2013-01-21 1:52 ` Minchan Kim
2013-01-21 1:52 ` Minchan Kim
2013-01-21 14:39 ` Rik van Riel
2013-01-21 14:39 ` Rik van Riel
2013-01-22 0:09 ` Minchan Kim
2013-01-22 0:09 ` Minchan Kim
2013-02-05 1:43 ` Minchan Kim
2013-02-05 1:43 ` Minchan Kim
2013-01-09 6:21 ` [PATCH 2/2] mm: forcely swapout when we are out of page cache Minchan Kim
2013-01-09 6:21 ` Minchan Kim
2013-01-10 0:26 ` Andrew Morton
2013-01-10 0:26 ` Andrew Morton
2013-01-10 2:23 ` Minchan Kim
2013-01-10 2:23 ` Minchan Kim
2013-01-10 21:58 ` Andrew Morton
2013-01-10 21:58 ` Andrew Morton
2013-01-11 4:43 ` Minchan Kim
2013-01-11 4:43 ` Minchan Kim
2013-01-16 0:09 ` Andrew Morton [this message]
2013-01-16 0:09 ` Andrew Morton
2013-01-16 0:32 ` Sonny Rao
2013-01-16 0:32 ` Sonny Rao
2013-01-16 0:50 ` Andrew Morton
2013-01-16 0:50 ` Andrew Morton
2013-01-16 1:21 ` Sonny Rao
2013-01-16 1:21 ` Sonny Rao
2013-01-16 4:47 ` Minchan Kim
2013-01-16 4:47 ` Minchan Kim
2013-01-16 20:08 ` Sonny Rao
2013-01-16 20:08 ` Sonny Rao
2013-01-16 4:43 ` Minchan Kim
2013-01-16 4:43 ` Minchan Kim
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