From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Date: Tue, 19 Jul 2011 20:27:54 +0100 From: Matthew Garrett Subject: Re: [RFC][PATCH -mmotm 1/4] Add static function calls of pstore to kexec path Message-ID: <20110719192754.GA25268@srcf.ucam.org> References: <5C4C569E8A4B9B42A84A977CF070A35B2C199C64C3@USINDEVS01.corp.hds.com> <20110719183506.GA23770@srcf.ucam.org> <5C4C569E8A4B9B42A84A977CF070A35B2C199C64D6@USINDEVS01.corp.hds.com> <20110719185213.GA24420@srcf.ucam.org> <5C4C569E8A4B9B42A84A977CF070A35B2C199C64E5@USINDEVS01.corp.hds.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <5C4C569E8A4B9B42A84A977CF070A35B2C199C64E5@USINDEVS01.corp.hds.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: kexec-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=twosheds.infradead.org@lists.infradead.org To: Seiji Aguchi Cc: "dzickus@redhat.com" , Satoru Moriya , "dle-develop@lists.sourceforge.net" , "tony.luck@intel.com" , "hpa@zytor.com" , "kexec@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-mtd@lists.infradead.org" , "Eric W. Biederman" , KOSAKI Motohiro , Jarod Wilson , Americo Wang , Andrew Morton , Vivek Goyal On Tue, Jul 19, 2011 at 03:14:22PM -0400, Seiji Aguchi wrote: > > >And how does that handle the case where we're halfway through a pstore > >access when the NMI arrives? ERST, at least, has a complex state > >machine. You can't guarantee what starting one transaction without > >completing one that was in process will do. > > As for ERST, write access is protected by raw_spin_trylock_irqsave(&erst_lock). > Are there anything I'm missing? If there's already locking involved, what benefit does removing the lock in the pstore code give? You'll just hang when you hit the erst code instead of the pstore code. -- Matthew Garrett | mjg59@srcf.ucam.org _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 19 Jul 2011 20:27:54 +0100 From: Matthew Garrett To: Seiji Aguchi Subject: Re: [RFC][PATCH -mmotm 1/4] Add static function calls of pstore to kexec path Message-ID: <20110719192754.GA25268@srcf.ucam.org> References: <5C4C569E8A4B9B42A84A977CF070A35B2C199C64C3@USINDEVS01.corp.hds.com> <20110719183506.GA23770@srcf.ucam.org> <5C4C569E8A4B9B42A84A977CF070A35B2C199C64D6@USINDEVS01.corp.hds.com> <20110719185213.GA24420@srcf.ucam.org> <5C4C569E8A4B9B42A84A977CF070A35B2C199C64E5@USINDEVS01.corp.hds.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5C4C569E8A4B9B42A84A977CF070A35B2C199C64E5@USINDEVS01.corp.hds.com> Cc: "dzickus@redhat.com" , Satoru Moriya , "dle-develop@lists.sourceforge.net" , "tony.luck@intel.com" , "hpa@zytor.com" , "kexec@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-mtd@lists.infradead.org" , "Eric W. Biederman" , KOSAKI Motohiro , Jarod Wilson , Americo Wang , Andrew Morton , Vivek Goyal List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, Jul 19, 2011 at 03:14:22PM -0400, Seiji Aguchi wrote: > > >And how does that handle the case where we're halfway through a pstore > >access when the NMI arrives? ERST, at least, has a complex state > >machine. You can't guarantee what starting one transaction without > >completing one that was in process will do. > > As for ERST, write access is protected by raw_spin_trylock_irqsave(&erst_lock). > Are there anything I'm missing? If there's already locking involved, what benefit does removing the lock in the pstore code give? You'll just hang when you hit the erst code instead of the pstore code. -- Matthew Garrett | mjg59@srcf.ucam.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751351Ab1GST2A (ORCPT ); Tue, 19 Jul 2011 15:28:00 -0400 Received: from cavan.codon.org.uk ([93.93.128.6]:50887 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751092Ab1GST17 (ORCPT ); Tue, 19 Jul 2011 15:27:59 -0400 Date: Tue, 19 Jul 2011 20:27:54 +0100 From: Matthew Garrett To: Seiji Aguchi Cc: "kexec@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-mtd@lists.infradead.org" , "Eric W. Biederman" , Vivek Goyal , KOSAKI Motohiro , Americo Wang , "tony.luck@intel.com" , Andrew Morton , Jarod Wilson , "hpa@zytor.com" , "dzickus@redhat.com" , "dle-develop@lists.sourceforge.net" , Satoru Moriya Subject: Re: [RFC][PATCH -mmotm 1/4] Add static function calls of pstore to kexec path Message-ID: <20110719192754.GA25268@srcf.ucam.org> References: <5C4C569E8A4B9B42A84A977CF070A35B2C199C64C3@USINDEVS01.corp.hds.com> <20110719183506.GA23770@srcf.ucam.org> <5C4C569E8A4B9B42A84A977CF070A35B2C199C64D6@USINDEVS01.corp.hds.com> <20110719185213.GA24420@srcf.ucam.org> <5C4C569E8A4B9B42A84A977CF070A35B2C199C64E5@USINDEVS01.corp.hds.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5C4C569E8A4B9B42A84A977CF070A35B2C199C64E5@USINDEVS01.corp.hds.com> User-Agent: Mutt/1.5.20 (2009-06-14) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: mjg59@cavan.codon.org.uk X-SA-Exim-Scanned: No (on cavan.codon.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 19, 2011 at 03:14:22PM -0400, Seiji Aguchi wrote: > > >And how does that handle the case where we're halfway through a pstore > >access when the NMI arrives? ERST, at least, has a complex state > >machine. You can't guarantee what starting one transaction without > >completing one that was in process will do. > > As for ERST, write access is protected by raw_spin_trylock_irqsave(&erst_lock). > Are there anything I'm missing? If there's already locking involved, what benefit does removing the lock in the pstore code give? You'll just hang when you hit the erst code instead of the pstore code. -- Matthew Garrett | mjg59@srcf.ucam.org