From: Pavel Machek <pavel@ucw.cz>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Oliver Neukum <oneukum@suse.com>,
Dave Chinner <david@fromorbit.com>,
Henrique de Moraes Holschuh <hmh@hmh.eng.br>,
Len Brown <len.brown@intel.com>, Len Brown <lenb@kernel.org>,
One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>,
Alan Stern <stern@rowland.harvard.edu>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linux PM list <linux-pm@vger.kernel.org>
Subject: Re: [PATCH 1/1] suspend: delete sys_sync()
Date: Tue, 4 Aug 2015 21:54:47 +0200 [thread overview]
Message-ID: <20150804195447.GA28564@amd> (raw)
In-Reply-To: <5271193.sYRdkO0AkU@vostro.rjw.lan>
On Fri 2015-07-10 01:22:55, Rafael J. Wysocki wrote:
> On Thursday, July 09, 2015 09:32:51 AM Oliver Neukum wrote:
> > On Thu, 2015-07-09 at 00:03 +0200, Rafael J. Wysocki wrote:
> >
> > > Nothing and I'm not discussing that (I've said that already at least once in
> > > this thread).
> > >
> > > What I'm questioning is the "why" of calling sys_sync() from the kernel.
> >
> > That's strictly speaking two questions
> >
> > 1. Why do it in the kernel
> >
> > That is easy. It closes the window of a race condition.
> >
> > 2. Why do it at all
> >
> > In essence because the system becomes inactive. For example we say that
> > data hits the disk after 30s maximum. We cannot meet such a limit unless
> > we sync.
>
> Absolute deadlines are not guaranteed to be met at all in general when
> system suspend is used, at least from the user space perspective, so the
> above is quite a bit of an overstretch.
Well, this particular deadline _was_ guaranteed before Len's patch,
and it is useful one, too:
"if notebook is not on, it is ok to pull the USB stick".
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2015-08-04 19:54 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-08 7:08 [PATCH 1/1] suspend: delete sys_sync() Len Brown
2015-05-08 14:34 ` Alan Stern
2015-05-08 16:36 ` Len Brown
2015-05-08 19:13 ` One Thousand Gnomes
2015-05-08 19:32 ` Len Brown
2015-05-08 19:52 ` One Thousand Gnomes
2015-05-08 20:39 ` Rafael J. Wysocki
2015-05-08 20:30 ` Rafael J. Wysocki
2015-05-09 19:59 ` Alan Stern
2015-05-09 20:25 ` Henrique de Moraes Holschuh
2015-05-11 20:34 ` Len Brown
2015-05-12 6:11 ` Oliver Neukum
2015-06-25 17:11 ` Henrique de Moraes Holschuh
2015-06-30 20:04 ` Len Brown
2015-07-01 12:21 ` Henrique de Moraes Holschuh
2015-07-02 3:07 ` Len Brown
2015-07-03 1:42 ` Dave Chinner
2015-07-04 1:03 ` Rafael J. Wysocki
2015-07-04 8:50 ` Geert Uytterhoeven
2015-07-05 23:25 ` Rafael J. Wysocki
2015-07-04 14:19 ` Alan Stern
2015-07-05 23:28 ` Rafael J. Wysocki
2015-07-06 11:06 ` Pavel Machek
2015-07-06 13:59 ` Rafael J. Wysocki
2015-07-07 10:25 ` Pavel Machek
2015-07-07 12:22 ` Rafael J. Wysocki
2015-07-06 0:06 ` Dave Chinner
2015-07-06 11:11 ` Pavel Machek
2015-07-06 13:52 ` Rafael J. Wysocki
2015-07-07 1:17 ` Dave Chinner
2015-07-07 12:14 ` Rafael J. Wysocki
2015-07-07 13:16 ` Oliver Neukum
2015-07-07 14:32 ` Rafael J. Wysocki
2015-07-07 14:38 ` Oliver Neukum
2015-07-07 15:03 ` Alan Stern
2015-07-07 22:20 ` Rafael J. Wysocki
2015-07-08 11:20 ` Pavel Machek
2015-07-08 14:40 ` Alan Stern
2015-07-08 22:04 ` Rafael J. Wysocki
2015-07-07 22:11 ` Rafael J. Wysocki
2015-07-08 7:51 ` Oliver Neukum
2015-07-08 22:03 ` Rafael J. Wysocki
2015-07-09 7:32 ` Oliver Neukum
2015-07-09 23:22 ` Rafael J. Wysocki
2015-08-04 19:54 ` Pavel Machek [this message]
2015-07-08 11:17 ` Pavel Machek
2015-07-07 13:42 ` Takashi Iwai
2015-07-06 10:15 ` Ming Lei
2015-07-06 10:03 ` Pavel Machek
2015-05-11 1:44 ` Dave Chinner
2015-05-11 20:22 ` Len Brown
2015-05-12 22:34 ` Dave Chinner
2015-05-13 23:22 ` NeilBrown
2015-05-14 23:54 ` Dave Chinner
2015-05-15 0:34 ` Rafael J. Wysocki
2015-05-15 0:40 ` Ming Lei
2015-05-15 0:59 ` Rafael J. Wysocki
2015-05-15 5:13 ` Ming Lei
2015-05-15 10:35 ` One Thousand Gnomes
2015-05-18 1:57 ` NeilBrown
[not found] ` <CAJvTdKn_0EZ0ZuqO2e4+ExD8kFWcy78fse4zHr3uFZODOroXEg@mail.gmail.com>
2015-06-19 1:09 ` Dave Chinner
2015-06-19 2:35 ` Len Brown
2015-06-19 4:31 ` Dave Chinner
2015-06-19 6:34 ` Len Brown
2015-06-19 23:07 ` Dave Chinner
2015-06-20 5:26 ` Len Brown
2015-05-15 1:04 ` NeilBrown
2015-05-15 14:20 ` Alan Stern
2015-05-15 14:32 ` Alan Stern
2015-05-15 14:19 ` Alan Stern
2015-07-06 10:07 ` Pavel Machek
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