From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Berg Subject: Re: [RFC] Add the "icebox" Date: Wed, 07 Nov 2007 16:54:53 +0100 Message-ID: <1194450893.4470.51.camel@johannes.berg> References: Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============8667409887049421007==" Return-path: In-Reply-To: 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: Alan Stern Cc: Linux-pm mailing list List-Id: linux-pm@vger.kernel.org --===============8667409887049421007== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-5goljiisFof8z06XjtpC" --=-5goljiisFof8z06XjtpC Content-Type: text/plain Content-Transfer-Encoding: quoted-printable > The idea was that kernel threads would have a PM-notifier routine and > would be sent to the icebox when the routine gets a > PM_{HIBERNATION|SUSPEND|RESTORE}_PREPARE message. Presumably the > notifier routine wouldn't return until the thread was safely on its way > to the icebox. >=20 > You are correct that this would require some additional locking, plus=20 > the extra notifier routine, plus ways to handle timeouts, plus maybe=20 > some other stuff. That's why I said in my earlier message that=20 > keeping the freezer around for these sorts of threads would be a good=20 > idea -- it would avoid all this new overhead. Ok, makes sense, thanks for the explanation. > The icebox would still be useful, however, for user tasks that try to > do I/O after a system-sleep transition has begun. Right now this can't > happen, thanks to the freezer (except that it _can_ happen on PPC where > the freezer isn't used for suspend). Once the freezer no longer > affects user tasks, kernel drivers will have to do _something_ when a > user task submits an I/O request during a system sleep. That > "something" will be to go to the icebox. Right, ok. I wish I could change powerpc, I've been maintaining a patch for months now, but Paul seems to be dead set against it. Not only does that fix these things, but also we get to use the /sys/power/state API... johannes --=-5goljiisFof8z06XjtpC Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Comment: Johannes Berg (powerbook) iQIVAwUARzHfzKVg1VMiehFYAQLV1w//ST3JvSZ3CNBt1l6O1Sc1XVDQCrWF3r0h Rt/1F/fMyIF4lHHTUFg2mSP2mVRd7S/8hZwGYxLdHUUuMtZp/P7Wr09w0TlGbWgQ D1FoDDN2a5lUSNZ2WEZzctMauLa3zxPj0kAEWQpCsDUBHWZtF0UJogIhrUy6lWlS D360VwIN4EEjFTa3o/LBHbD8C73vvdddan99jpqFrdfjNZQwEWc5GLP6K5LJjHND 9f+SLl3bQxLH+j25vBGZMHSDxoTMGWJXRfXC35tefhp24bG5vGxxOf6l94K5SMpK EeGqWRJvC2SCLAzRBrZvx23kSFgqi8eiwrirg0sXz8zYM1jF1LAb2IoMucb4Oklz NvZWsz3iCp0tyOe2FHj4fVUJHq15bBtnF+sF0RD2lfghzDa96xOo4/L4RZkIkwRV kf/XOm0dhnWMA04NeUp/hiBG/dbwwn0TY2M9AcIdNoCh40XaP+4rcSw9IOysHx7x /dqLQi4efOC952isrMItCeCLyL1F6q6bGgmnHZzJr0dRYbe5e0LPKPGRL/plwakp A7V+WyVSXv0nLa0562nIzzhdTsTzkHkT8LMzlb6JCygwskRTSQXdRIi8Ex6DfgSl jxabMfgeuf+zyK+HZ6lU+yypxJ0/TzVeTpXBis9v76DqQKUVZWy2OQGmTWh9cTCY 7ahdSWGiWOM= =eRxV -----END PGP SIGNATURE----- --=-5goljiisFof8z06XjtpC-- --===============8667409887049421007== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline --===============8667409887049421007==--