From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nigel Cunningham Subject: Re: [RFC/PATCH 2/2] kernel: don't update load average during snapshot/shutdown Date: Sun, 29 Apr 2007 08:52:32 +1000 Message-ID: <1177800752.7652.0.camel@nigel.suspend2.net> References: <1177715134.4737.194.camel@nigel.suspend2.net> <46330550.8020005@cs.helsinki.fi> <200704281249.06774.rjw@sisk.pl> Reply-To: nigel@nigel.suspend2.net Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1640977822836242843==" Return-path: In-Reply-To: <200704281249.06774.rjw@sisk.pl> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Mime-version: 1.0 Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: "Rafael J. Wysocki" Cc: Pekka Enberg , linux-pm@lists.osdl.org, Pavel Machek List-Id: linux-pm@vger.kernel.org --===============1640977822836242843== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-xVoxMEvG91UbMq6Bxyli" --=-xVoxMEvG91UbMq6Bxyli Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Hi. On Sat, 2007-04-28 at 12:49 +0200, Rafael J. Wysocki wrote: > On Saturday, 28 April 2007 10:26, Pekka Enberg wrote: > > Nigel Cunningham wrote: > > > I therefore have to ask: Please. Go away. Hand the maintainership of > > > hibernation over to Rafael. Work on things you do care about and wher= e > > > you do want to see a fully functional implementation. But stop being = a > > > hindrance to us making Linux hibernation support everything that it > > > ought to be. > >=20 > > [snip] > >=20 > > Please. The load average is a problem and no the fix is not to make=20 > > kernel/timer.c worse for everybody but to snapshot the load averages=20 > > _before_ I/O and restore them after resume. >=20 > I'm having an impression that this problem is suspend2-specific. With sw= susp > we can have it only if the writing of snapshot fails. >=20 > Namely, with swsusp we have the pre-snapshot value of the load average in= the > image and it should be, so to speak, "normal". Then, once we've restored= the > image, this "normal" value gets recovered and everything is fine. If the= writing > of image fails, we can have a "wrong" (i.e. too high) value of the load a= verage > afterwards, but then this is an error condition anyway. At least, as a u= ser, I > can expect some glitches to happen after a failing hibernation. >=20 > With suspend2, in turn, the contents of LRU pages are saved before we cre= ate > the snapshot. They can be compressed etc. in the process, so the load av= erage > can grow quite substantially and this "unusual" load average is then > snapshotted. Hence, the problem appears after the restore. I think the > solution could be to save the post-tasks-freezing load average and restor= e it > right before snapshotting, but that's only needed for suspend2. Yes, you and Pekka are both right. That would work too. Regards, Nigel --=-xVoxMEvG91UbMq6Bxyli Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQBGM9AwN0y+n1M3mo0RAo90AJ4r8+f/bZBuyHJtbwYBozT7BL2/kgCg1fMV oXGPYepfcA6VSiPrddB4UVU= =fKV9 -----END PGP SIGNATURE----- --=-xVoxMEvG91UbMq6Bxyli-- --===============1640977822836242843== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline --===============1640977822836242843==--