Re: [PATCH 1/1] suspend: delete sys_sync()

On Fri 2015-07-10 01:22:55, Rafael J. Wysocki wrote:

On Thursday, July 09, 2015 09:32:51 AM Oliver Neukum wrote:

quoted

On Thu, 2015-07-09 at 00:03 +0200, Rafael J. Wysocki wrote:

quoted

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
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