From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: linux-pm@lists.linux-foundation.org
Subject: Re: shrinking memory for suspend?
Date: Mon, 30 Apr 2007 17:10:42 +0200 [thread overview]
Message-ID: <200704301710.43329.rjw@sisk.pl> (raw)
In-Reply-To: <1177943076.5102.83.camel@johannes.berg>
Hi,
On Monday, 30 April 2007 16:24, Johannes Berg wrote:
> Hi,
>
> Paul Mackerras noticed that even for suspend to ram we currently free
> some memory in suspend_prepare. Is that necessary because we freeze
> userspace so devices can allocate a bit of memory for suspend?
I don't think it's related to the freezing of user space. You can allocate
memory with all of the user space frozen just fine. I'd say it's related to
the freezing of kernel threads, rather.
> Why do we freeze userspace anyway?
Well, let me quote Linus:
"I _do_ realize the IO request queue issues, and that we cannot actually do
s2ram with some devices in the middle of a DMA. So we want to be able to
avoid *that*, there's no question about that. And I suspect that stopping
user threads and then waiting for a sync is practically one of the easier
ways to do so."
Greetings,
Rafael
next prev parent reply other threads:[~2007-04-30 15:10 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-30 14:24 shrinking memory for suspend? Johannes Berg
2007-04-30 15:09 ` Alan Stern
2007-04-30 15:10 ` Rafael J. Wysocki [this message]
2007-04-30 15:09 ` Johannes Berg
2007-04-30 19:57 ` Rafael J. Wysocki
2007-05-02 11:29 ` Pavel Machek
2007-05-02 14:02 ` Johannes Berg
2007-05-03 10:17 ` Rafael J. Wysocki
2007-05-03 10:34 ` Paul Mackerras
2007-05-03 10:45 ` Rafael J. Wysocki
2007-05-03 12:51 ` Paul Mackerras
2007-05-03 13:15 ` Rafael J. Wysocki
2007-05-03 16:34 ` Pavel Machek
2007-05-03 14:34 ` Alan Stern
2007-05-03 16:39 ` Rafael J. Wysocki
2007-05-03 23:32 ` Paul Mackerras
2007-05-04 9:02 ` Rafael J. Wysocki
2007-05-04 10:49 ` Paul Mackerras
2007-05-04 12:11 ` Rafael J. Wysocki
2007-05-04 15:05 ` Alan Stern
2007-05-03 11:33 ` Johannes Berg
2007-05-03 12:56 ` Rafael J. Wysocki
2007-05-04 10:48 ` Johannes Berg
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